REPORT ON ROOFS by noidarocker

VIEWS: 11 PAGES: 108

									A roof is the covering on the uppermost part of a building. A roof protects the building and its
contents from the effects of weather. The characteristics of a roof are dependent upon the
purpose of the building that it covers, There is a wide spectrum of roof covering materials, which
are used for different structural, aesthetic, economic, and performance reasons. Roof designs
have developed from just being a weather performance element to an architectural trademark that
can be environment-friendly, structurally sound, reasonably priced and aesthetically attractive.

Roofing systems have come along way
Early humans didn’t have the luxury of early morning coffee, couldn’t hang their feet off the bed
before taking the first morning step and the idea of a hot shower had not even been dreamed up

When it came to building dwellings, there were pictures to get ideas from, no blue prints to
follow and they couldn’t walk around the neighborhood and see what the Johnsons were doing.
When mankind stopped living in caves they couldn’t call up the nearest construction company
and tell the contractor to build a 3 bedroom house with 2 bathrooms. They had to make their
dwellings from scratch.
According to archeologists, in 3100 BC writing started and
history was put down on tablets for everybody to read.
Before then, cave wall drawings and drawings in the dirt
would have been the only way to sketch ideas for dwellings.

What was the first roof ever built? A good question for
which there isn’t an answer yet. The earliest roof used
readily available materials from the surrounding terrain and
needed to be portable. Most likely the first roof was covered
with dirt, underlayed with branches and supported by
wooden beams. Areas without plentiful wood could have
used mammoth and whale bones as beams.

Over 30,000 years ago, Aborigines used bark from birch
trees for their roofs. But in places like Siberia where birch
trees were not available, hunter gathers used mammoth
skins to cover their dwellings. Other nomadic people such as
Folsom man in North America used Reindeer skin for roofs.

In colder climates, the first houses were dug into the ground,
not unlike the caves they left, but weren’t used year around.
More advanced civilizations used thatch and reeds to build
dwelling roofs. The dwellings were more permanent
structures but were designed to be easily dismantled because
of spring floods. Later these dwellings became permanent
when built on piled or rock foundations.

Agriculture based people had more time to spend building a
dwelling and had the opportunity to search out different
materials. Agriculture based people had more time to spend
building a dwelling and had the opportunity to search out
different materials. Natural asphalt was first used as early
as 30,000 BC as a
waterproofing technique, something that is still used today.
Ceramic tiles, another familiar roofing product, was created
around 10,000 BC by the Chinese and shortly after in the
Middle East.
Parts of a roof
There are two parts to a roof, its supporting structure and its outer skin, or uppermost
weatherproof layer. In a minority of buildings, the outer layer is also a self-supporting structure.

The roof structure is generally supported upon walls, although some building styles, for example,
geodesic and A-frame, blur the distinction between wall and roof.

The elements in the design of a roof are :-

      the material
      the construction
      the durability

The material of a roof may range from banana leaves, wheaten straw or seagrass to lamininated
glass, aluminium sheeting and precast concrete. In many parts of the world ceramic tiles have
been the predominant roofing material for centuries.

The construction of a roof is determined by its method of support and how the underneath space
is bridged and whether or not the roof is pitched. The pitch is the angle at which the roof rises
from its lowest to highest point. Most domestic architecture, except in very dry regions, has roofs
which are sloped, or pitched. example thatch, require a steep pitch in order to be waterproof and
durable.[1] Other types of roofing, for example pantiles, are unstable on a steeply pitched roof but
provide excellent weather protection at a relatively low angle. In regions where there is little
rain, an almost flat roof with a slight run-off provides adequate protection against an occasional

The durability of a roof is a matter of concern because the roof is often the least accessible part
of a building for purposes of repair and renewal, while its damage or destruction can have
serious effects.
The New Roofing Materials

Invisible to most people, roofing materials have undergone a dramatic transformation during the
last decade or two. Certainly, the quest for lower cost and better performing buildings has
influenced roofing material requirements.

The use of polymers has played a large part in enabling the fulfillment of these requirements for
bituminous roofing materials. Bituminous waterproofing has been re-invented to become an
advanced, proven, reliable and resilient waterproofing material that is fit for purpose over a large
climatic temperature range, exhibits longevity and is user-friendly during application.

Kraton polymers have been at the forefront of this revolution, with their first application in
roofing felts in the early seventies. Kraton Polymers continues to push the boundaries providing
solutions for developing challenges.

Photo: courtesy of Andersons Waterproofing


Corrugated iron, turf or thick layers of liquid applied, straight run
bitumen is what most people associate with flat roofs of old.

Leaks and surface cracking add to the rustic image most people
remember of these dark grey bituminous roofing materials. And regular
maintenance using pots of fuming bitumen contributed to the old
fashioned image.

Flat roofs typically were only applied to sheds and other simple buildings. How things have

Photo: traditional turf roof houses in Iceland


Flat roofs have now become accepted as a reliable and lasting roof
construction solution for commercial and residential buildings. This has
been achieved because high quality roofing materials, such as Kraton
polymer modified roofing felts, have long been used and applied in a
professional fashion.

The extensive and often legislated use of insulation materials has also resulted in exposure of the
roofing membrane to much more extreme temperatures, because of the lack of moderation from
heat flows to and from the building. Unmodified materials could not therefore continue to be
used. The formulation of roofing felt using the wide variety and versatility of Kraton polymers
allows an adaptation of the product to hot, cold and to climates with large temperature extremes.
Elasticity and toughness obtained when using Kraton polymer modified roofing felts will help
maintain performance over long periods of time.

Aesthetics have become more important in recent years. The use of colored chippings or thin
metal overlays have changed the look of products.

Changes for the Future

Future requirements are expected to go beyond the waterproofing
function of the membrane. Aesthetic, safety, cost and environmental
requirements will drive change in the coming years.

No matter what kind of roof you have or want, all roofs are made up of a few basic components.

The rafters and trusses that support the decking.

The boards or sheet materials fastened to the roof rafters to cover the house.

Sheets of asphalt-saturated material. Used as a second layer of protection for the roof decking.

Roof covering
Shingles, tiles, etc., that protect the decking from weather. This is the first layer of protection for your
roof decking.

The features of the roof's design such as slope, shape, layout, etc., that determine its ability to shed water.

Sheet metal (in most cases) laid into the various joists and valleys of a roof system to prevent water leaks.

Roofing Pitch
Also known as "slope", pitch is the measure of how "steep" a roof is. For example, if a roof is "4 in 12",
the roof rises 4 inches for every horizontal run of 12 inches. The pitch of the roof is a big factor in
determining the kinds of materials that can be used and the longevity of the roof. Usually, a steeper roof
(higher pitch) will last longer due to its better drainage capabilities.

Roof Type
What kind of roofing system you need or can obtain will depend largely on the type of roof currently on
your home.
Seamless Gutters

What are Seamless Gutters?

Continuous Rain Guttering, Also known as Seamless Guttering "Seamless Gutters" is nationally recognized as the most
popular form of guttering. Seventy-five percent of all guttering installed throughout the nation is continuous. Its
popularity is easily understood because...

       Continuous Rain Guttering, Seamless Guttering, eliminates unsightly seams
       Reduces the possibility of leaks
       Baked on enamel finish never needs painting
       Protects the beauty of your home and landscaping
       Formed on the job site for exact measurements
       Most jobs are completed in one day
       Many colors from which to choose from

                                                Basic Seamless Gutter Designs

                       "K" Style Gutter                                           Half Round Style Gutter

The purpose of guttering systems is to collect water (rain) from the roofing area and disperse the water away from your
home. Properly configured downspouts (leaders, drain pipes) are very essential. A faulty guttering system can contribute
to damage to Soffit & Fascia, Shingles, Building Foundations, Driveways, Walkways, Landscaping.

Guttering systems require maintenance to insure protection for your home. Make sure your gutters are free from debris,
leaves, granules from shingles, birds nest. The extreme exposure to nature can also cause sealant failures. Snow & Ice can
loosen fasteners and should be repaired immediately to prevent costly repairs.

(We always recommend a professional for maintaining your Guttering System)

Seamless Gutters
There are many different gutter materials to choose from, including steel, aluminum, vinyl, copper. Many types of gutters
(steel and vinyl in particular) are sold in 10’ lengths and require dozens of seams fastened with slip fittings, each one is a
weak spot and a potential leak site. Another alternative well worth considering is the installation of seamless aluminum
gutters. Seamless gutters must be fabricated on-site by a professional contractor.
The term seamless gutters can be confusing because there are seams in the system. The seams are only at the corners and
downspout outlets.These joints are fastened more securely and sealed for stability and leak resistance. The Seamless
Gutter itself is continuous which makes them both strong and visually more appealing.

How to Determine Gutters & Downspouts
The most commonly used is the 5" Seamless Gutter

       2 x 3 downspout for every 600 square ft. of roofing area.
       3 x 4 downspout for every 1200 square ft. of roofing area.
       For example: If your roof is 40ft. long and 16ft. to the peak.
       40 x 16 = 640square ft. area *Requires (2) 2x3 downspouts or (1) 3x4 downpout
       6" Seamless Gutters may be required to accomadate steep pitch roofs or slate & tile and should always be used
        with 3x4 downspouts.

              Residential Roofing Materials
                Carlson Brothers has helped homeowners install and repair their roofs for more than 15 years. We use
                only the highest quality roofing supplies and products on the market, and offer free estimates for all
                prospective clients. Whether you need a new roof, repairs or custom roofing, we offer a service to meet
                your needs.

                       Flat & Sloped Roofs
                       Shingled, Tiled & Wood Roofs
                       Wide Variety Of Colors & Styles
                       New Metal Roofs
                       Installation Warrantee
                       25 – 50 Year Guarantees

                To request a free quote, please use our estimate form or contact us by telephone.

                                                             (888) 882-2757

                Find the Right Roofing Contractor for Your Home
                When time is money, Carlson Brothers takes the guesswork and uncertainty out of finding the right
roofing company for your need. We help you protect yourself and your investments by utilizing licensed
and bonded roofing contractors.

Whether you need a new roof, want to look into new roofing materials to patch or replace your roof, or
just want to find out the meaning of all those roofing terms your contractor has been using, Carlson
Brothers will guide you in the right direction.

3 Reasons To Use Carlson Brothers
Any major home repair can seem daunting; replacing or repairing a roof is no exception. So how do you
make the right decisions about the roofing process? Carlson Brothers can help.

       Carlson Brothers can help you decide if you need a new roof.
       Carlson Brothers can inform you about important roofing considerations.
       Carlson Brothers can even schedule on-site estimates for you!
       Roof of Steel
        Matt Weber

       Strength and style: Everybody wants some — and when it comes to roofing — everyone
        can have it. The durability and longevity of a metal roof is probably the biggest selling
        point for using metal as a roofing material. But the striking appearance of today's metal
        roofs is what makes the decision even easier. Choose from multiple styles, colors and
        textures to settle on a new metal roof that enhances the visual style of your home and
        withstands hail, fire, earthquakes and hurricane-force winds.
       While weather exposure can cause asphalt roofing to require reinstallation every 12 to 20
        years, a metal roof can withstand just about all the harsh weather Mother Nature can dish
        out. Other roofing materials such as wood shingles and tile have varying degrees of
        weather-related problems as well. Even concrete tile roofs experience problems with
        freeze/thaw cycles in colder climates. But a metal roof retains its good looks and
    performance for years, which is why most of them come with a 30- to 50-year warranty.
    And recoating a metal roof can usually extend its life even further.
   The wide variety of styles is the second big plus for metal roofs. Many homeowners are
    surprised to learn that metal roofs come in a wide variety of patterns and designs that fit
    into any neighborhood décor. Many of these options look just like typical roofing styles,
    such as cedar shake, slate, tile, shingle and continuous-seam vertical panels.

   A Strong Investment
   A metal roof is certainly a big investment; because it's a premium material, you can count
    on a new metal roof costing at least twice as much as an asphalt-shingle roof. You're
    paying for long-term quality as well as the skilled professional installation required. The
    price is comparable to tile or cedar-shake roofing, but it's an investment that will pay off
    in the end. While other premium roof systems look good at first, they break down over
    time from exposure to wind, rain and harmful ultraviolet rays. If you plan on staying in
    your home for years to come, then consider the cost over a
   30-year period; when you would otherwise have to replace two or more asphalt roofs,
    your one-time investment in a metal roof will save money in the long run. It will stand
    strong in the face of snow, hailstorms or even wildfires. And many products are tested
    and even warrantied to resist wind gusts up to 120 miles (that's equal to an F2 tornado,
    for those of you living in “Tornado Alley”).
   Your insurance costs may even see a silver lining in the metal option. According to the
    Metal Roofing Alliance, some insurance companies in states such as Texas offer
    homeowners with metal roofs up to 35-percent discounts on coverage.
   And the cost savings may not stop there. Metal roofs are excellent insulators and may
    save on heating costs in some situations. A light-colored metal roof can actually reflect a
    portion of the sun's radiant energy, saving you money on cooling costs. New infrared-
    reflective pigments can result in high reflectivity in dark colors as well. And considering
    the low effort involved with maintaining the roof, which requires little more than an
    occasional spray-off with a garden hose, a metal roof saves you labor as well. This low-
    maintenance aspect is why metal is used so often for commercial and institutional
    buildings. If companies want a worry-free roof for 30 to 50 years, they choose metal.

   The wildfires that plagued California in the summer of 2003 took a heavy toll on many
    homes. Shown here is a house with a strong metal roof that fared much better than its
    unfortunate neighbor, which didn't have the metal protection.
   One Tough Project
   Metal roofing is not your typical weekend DIY project. Installation requires a wide
    assortment of tools, accessories and special techniques that only come from working with
    professional installers. While writing this article, I requested Classic Products' installation
    manual for their Timber Creek Shake brand of steel roofing. Classic Products sent me the
    very detailed installation manual they supply to their professional installers — practically
    a textbook with highly detailed chapters on roofing gable channels, valleys, eaves, edge
    trim and more, as well as techniques and material lists for flashing virtually any type of
    roof protrusion. Suffice it to say, this issue of Extreme How-To doesn't have the page
    count to do the complex installation procedure justice. And you can bet instructions will
    vary from manufacturer to manufacturer.
   The smart move is to hire a contractor to install a moderate to complex metal roof. Look
    for a contractor who has substantial experience with the product you're choosing or has
    been trained by the manufacturer. Metal roofs do not all install in the same manner. Be
    sure to check your installer's references and make sure they have the proper licensing and
    insurance to work on your home.

   Installing a metal roof is a very challenging, professional-grade project. But if you can
    follow instructions and have an assortment of metalworking tools, you may be able to
    complete a simple continuous-seam installation.
   Selection
   Today's residential metal roofing is made to look exactly like common roofing material,
    only stronger and more durable. Check out some material samples to find the right style
    and finish to match your home and neighborhood. In addition to the many available
    shapes and styles, metal roofs are available in a wide array of colors and textures, such as
    metal shingles finished with ceramic-coated stone granules. Choose from a variety of
    metals as well — steel, tin, aluminum or copper.
   With regard to the many options available for metal roofs, make sure the product's design
    is appropriate for your home's construction. Most metal roofs require solid decking, but
    some can be installed over lathe boards or over wood shingles on lathe. Some of the more
    detailed designs can even be installed over slate roofs.

   First Steps
   It's no secret that roofing can be precarious work, so be very careful. As you reach the
    roof, inspect it for working hazards. Note the presence of loose roofing or weakened
    substrate, as well as protrusions such as pipe flashings, electrical wiring, nails, stabilizing
    wires and extensions cords. Look for moss growth or dampness that might make the roof
    slick or cause equipment to slip.
   Always be aware of your position on the roof relative to your surroundings. Take note of
    the locations of roof openings, edges, equipment, co-workers and other potential hazards.
   Check the manufacturer's recommendations regarding the minimum roof pitch required
    for installation. You can check the roof's pitch with a measuring square and a level. As
    shown in Diagram 1, a pitch of 3:12 will have 3 inches of rise to 12 inches of run.
   The next step is to determine if you will be able to place the new roof over old shingles,
    or if the old shingles will have to be removed. Again, check the recommendations for
    which subsurfaces you can install over. In some cases, a new metal roof may be applied
    over old asphalt shingles. Inspection of asphalt shingle roofs should include:
   • The number of layers of asphalt shingles — because of weight constraints, some local
    building officials limit the number of layers of old roof that can be covered.
   • The condition of the asphalt shingles — badly buckled or cupped shingles should be
    repaired to provide a flat, smooth surface.
    The process of removing old tiles is called a “tear-off” job. Remove the shingles with a
    wide, flat shovel, using a claw hammer and pry bar to loosen stubborn nails. Use the pry
    bar to loosen and remove the flashing around stacks and vents. A tear-off creates a lot of
    debris. As you move along, sweep the debris off the roof. Loose debris causes a hazard,
    especially on a steep roof. You should also have some method of collecting the debris
    and preventing it from damaging shrubs or flowers planted near the house. Dispose of the
    debris once you're finished; there will be a lot of it. Once the old shingles and asphalt
    paper covering the deck have been removed, carefully inspect the decking for rotting or
    holes and replace any damaged decking. Small holes can be patched over with pieces of
    flashing. Most manufacturers of metal roofing require at least a minimum 1/2-inch
    decking or equivalent, fastened per local building codes.
   The instructions included with your roofing system will specify the material and
    fastening requirements for the roofing underlayment. The underlayment must meet or
    exceed local building codes and fire requirements. A minimum 18-inch vertical and 6-
    inch horizontal lap is usually required. The underlayment should overhang all the roof
    edges by 1 1/2 inches, extend up all vent pipes at least 1 1/2 inch, and extend up all
    sidewalls and other penetrations by at least 6 inches. It is critical that the underlayment be
    installed correctly to avoid problems in the future. Metal roofing can develop
    condensation beneath it during certain weather conditions. The underlayment prevents
    this moisture from causing damage.
   For years, the standard underlayment has been one layer of 30-pound roofing felt. In the
    case of metal roofs that rest right against the underlayment, a “slip-sheet” of red rosin
    paper was often installed over the felt paper to keep it from sticking to the metal.
    However, new technology is bringing many polymer-based underlayments that work very
    well beneath metal roofs because they serve as their own slip-sheet. These polymer
    underlayments are also very light and easier to install than traditional felt paper.

   The Roofing Phase
   When it comes time to install the actual components of the metal roof, that's when this
    article takes a backseat to the instruction manual included with your roofing system. The
    basic rule of thumb is to follow the instructions to the letter. This is no time to get
   Make sure you or the installer use all matching components during the installation. A
    basic continuous-seam installation is generally done with lock-together metal panels, but
    even this job is not as simple as “tongue meets groove” — there is a raft of components
    and accessories required. All assembly parts must come from the same manufacturer and
    be specified for the make and model roofing system you've chosen. Don't try to mix and
    match components from another system, and don't try to fabricate pieces for the roof.
    These systems include special starting strips, clips, caps, edge pieces and more. All of
    these make up the total roof system and are designed to fit together to accommodate the
    proper ventilation requirements and the structural movement of the components due to
    changes in temperature.
   Metal roofing moves in response to temperature changes, and this needs to be accounted
    for in the installation phase. Manufacturers are very aware of this movement and take this
    into account in their installation instructions. This is why it is so crucial to follow all
    recommendations, paying close attention to the installation of fasteners, fastener length,
    type and placement. When the metal roofs move, if these fasteners are improperly
    installed, a leak may eventually develop. Many metal roofs allow for expansion and
    contraction by being designed to “float” on their clip fasteners. Other products are
    designed with folds in the metal, which have an “accordion effect” to allow for the
    metal's movement.
   Final Note
   One frequently asked question is: Would a metal roof be too heavy for certain types of
    homes, or for smaller structures like a detached garage or porch?
   The answer is no. A metal roof is, on average, 50-percent lighter than an asphalt shingle
    roof and 75-percent lighter than concrete tile, fiber-cement shakes and slate. With metal
    roofing, weight on a structure is not an issue.
   And given the fact that installation of a metal roof is such a complicated, professional-
    grade project, it may be a good idea for those extreme DIY'ers willing to take on such a
    project to try installing over a smaller structure, such as a porch or shed, before jumping
    into a full home re-roofing job. Test your skills on a manageable, simple installation
    before getting involved in a project that may be over your head, so to speak.

   Roofing Done the Right Way
    Kevin Hayes

   Roofing practices have changed a lot over the past 25 years, mostly due to ever-changing
    technology and materials. Fiberglass shingles, used often in residential buildings, are
    thinner and stiffer than asphalt shingles and can telegraph every imperfection. While
    these materials are often more durable and efficient than previous ones, they require more
    careful attention to detail during installation.
   There are five basic steps for building the best possible roof and avoiding costly callbacks
    and repairs:
    1. Start with a level nailing surface.
    2. Provide adequate ventilation.
    3. Nail and space panels correctly.
    4. Protect sheathing and carefully install felt.
    5. Install shingles according to manufacturer's guidelines.
   Start With a Level Nailing Surface
    Whether you're using plywood or oriented strand board (OSB), the first step in building a
    high-quality roof is to make sure you have a level nailing surface. You can check this
    with a 6- to 10-foot piece of lumber or a long carpenter's level. If one support is as little
    as 1/4 inch lower or higher than the one next to it, you might end up with an uneven roof.
    If needed, shim trusses or rafters to level the nailing surface, and install blocking to
    straighten any warped or bowed top chords of trusses or rafters.
   Provide Adequate Ventilation
    Attic ventilation began as a moisture-control strategy in cold climates, and many builders
    came to believe that vented attics could help to extend a shingle's life through cooling.
    Research, however, has done little to support this concept. What it does support is the fact
    that a roof has two main jobs: to prevent outside moisture from getting in, and to allow
    inside moisture, caused by human activity, to get out.
   Although venting requirements are not based on rigorous scientific research, your local
    building code should have the specific requirements you need to follow to pass
    inspections. All that said, here are the minimal guidelines for adequate roof ventilation:
      • Install 50 percent of vents near peaks or along ridges, and the rest at eaves or soffits.
       • The total free ventilating area can be 1/300 of the attic space if 50-80 percent of the
    ventilator area is near peaks or ridges, or if a vapor barrier is installed on the warm side
    of the ceiling. Otherwise, it must be 1/150 of the attic space. (International Residential
    Code, Section R806.2)
       • Vent exhaust air from the kitchen, bath or laundry through the roof to the outside.
       • Install baffles at the eaves, leaving at least 1 inch of clear space between framing
    and/or under roof sheathing to ensure that ceiling or roof insulation doesn't block
    ventilation paths. For vaulted or cathedral roofs, provide a free ventilation path from
    eaves to ridges between all rafters.
   Nail and Space Panels Correctly
    APA Field Service specialists often encounter incorrect nailing and panel spacing. “Many
    crews build ‘neat and tight' instead of ‘neat, tight and spaced right,'” says Roger Roatch,
    APA's field services manager for the western region.
   Proper spacing is especially important since wood expands and contracts as changes in
    ambient humidity also change the moisture content in the panels. If panels are butted
    tightly together, there is no room for expansion. When panels expand, they might bend up
    or down, or “buckle up” off trusses and rafters. And shingles will move with them, easily
    causing bulges, ridges and valleys.
   Unfortunately, roof problems may not appear for quite some time. For example, when the
    summer sun is high in the sky, the shadows cast across a roof are very short. As fall
    approaches, they begin to lengthen, often exposing even the slightest roofline
    imperfection. Only time will tell the level of skill and care that has gone into the roof
    installation. To stand the test of time and produce the best possible roof, follow this
      1. Position the first panel and use temporary fasteners at the corners, if needed, to
    square the panel on the framing. If necessary, trim ends to center panels on the framing.
       2. Install fasteners at one panel end.
       3. Remove fasteners at corners.
       4. Install intermediate fasteners, starting at the panel's edge. Use a chalk line or straight
    edge to align fasteners on the framing. Fasten panels in rows across the width, continuing
    this sequence along the length of the panel.
       5. To ensure contact with the framing while fastening the panel, stand over the framing
    near the fastener location. (Standing between framing while nailing can lock a sag into
    the roof sheathing.) Drive fasteners flush with the panel's surface.
       6. Leave 1/8 inch of space between adjacent panel ends and edge joints unless a panel
    manufacturer recommends otherwise. For a spacing tool, use an 8d common or 10d box
    nail, or panel edge clips.
       7. After sheathing is in place, you can easily saw-cut or kerf out any tight joints you
    might have missed. The saw blade will give you the 1/8-inch spacing you need. Kerfing,
    however, must be done before any buckling occurs because once buckling has occurred,
    the panels will retain a “memory” of the buckle and not flatten out completely.
       8. For improved performance, use thicker sheathing panels, panel edge clips, or panels
    with tongue-and-groove edges. Check local building codes before using panel edge clips
    since requirements depend on the relationship between a panel's span rating and the
    actual distance between framing members.
   This is the best procedure we've found for securely fastening roof panels and minimizing
    the effects of stress build-up during their expansion.
   Protect Sheathing and Carefully Install Felt
    After you've installed the roof sheathing, clean the surface thoroughly and then use a
    shingle underlayment felt conforming to ASTM D 226, Type I or ASTM D 4869, Type I.
    Do this as soon as possible to help protect the panels from exposure to weather. Besides
    cleaning the surface, be sure that all nails and staples are driven straight and made flush
    with shingles; otherwise, the tabs on shingles will poke up and look uneven.
   When you install roofing felt, smooth and flatten it as much as possible before fastening
    the shingles. Any wrinkles or bulges you leave may prevent the shingles from lying flat.
   Install Shingles According to Manufacturer's Guidelines
    Check the manufacturer's recommendations for installing shingles. Delay the installation
    of asphalt or fiberglass shingles as long as possible to give the sheathing time to adjust to
    humidity and moisture conditions. For the best appearance, use heavier weight, laminated
    or textured shingles, which will help to mask surface imperfections and reduce the risk of
    shingle ridging.
   For more information on quality roof construction, please refer to the variety of
    publications offered by APA, The Engineered Wood Association. For more information,
    visit or call the APA Help Desk at (253) 620-7400.
Finroof PVC roofing sheets are manufactured in varied thickness, ranging form 1.0mm
to 2.5mm. These sheets are suitable for roofing of Industries, warehouses, poultry and
dairy farms, stud farms, farm houses, weather sheds, parking lots, terrace gardens and
in host of other applications.

These sheets are also manufactured as transluscent sheets for the sky lighting
application in all the aforesaid profiles which are very useful in providing natural light
in Industries, warehouses or for that matter any installation where the natural light in
inadequate. This also results in power saving and reduces the lighting cost

---         ---


           Excellent corrosion resistance – Our roofing sheets are the best as regards
            the corrosion resistance. In corrosive atmospheres like high acidic vapours in
            chemical plant / picking plants, high carbon and carbon monoxide emission
            in industrial belts and also in urban areas due to automobiles exhaust, high
            salt content weather prevailing in coastal areas etc., our sheets are the best
            suited vis – a vis - any roofing material available in the market.

           Rust Proofness – In humid weather, in heavy rain falls and in hygroscopic
            atmosphere, metallic sheets get rusted and the Asbestos sheets tend to
            soften due to absorption of moisture. Our sheets do not absorb any
            moisture, nor do they get rusted. In high moisture conditions, our sheets are
            best suited.

           Thermal insulation – Our sheets have excellent thermal insulation
            properties and there is a sizable difference in temperatures ‘ above the roof’
            and ‘below and roof’. This is possible because our sheets reflect the heat
            into the space above the roof and whatever little heat is absorbed the same
            is not passed on to the inner spaces of the structure. (Minimum amount of
            heat is passed below the roof.) Due to these thermal insulation properties
  ---    ---
                                                                    Width    Net
          Profile                                      Pitch Depth                  Thickness
                                Profile                            Trimmed Coverage
          Name                                         (mm) (mm)                      (mm)
                                                                    (mm)    (mm)
                                                        250        40     1054       1000      1.8-2.5
                                                        76         18     1045       988       1.0-1.5
                                                        76         18     1086       1010      1.0-1.5
           Big 6                                        146        48     1086       1040      1.8-2.5

                                                ---          ---

                                  RECOMMENDED PURLIN SPACING

           Profile & Dimension of Industrial 250                Iron
                                                 Greca 76 / 18       Big 6 146 / 48
                    Wave              / 40                     76/18

                    Thickness               2 mm               1 mm          1 mm           2 mm

              Load (kg/m sq.)             90 120 150          50 80 110      50 80      90 120 150

                                                                                           1450 1350
               Spacing (mm)                              1050 900 800 850 750
                                    1450 1450 1400                                           1350
                                                                                           1500 1450
                                   1500 1450 1450 1100 1000 900 900 850
               Cladding (mm)                                                                 1400
                         Avaliable in standard lengths of 2.5, 3, 5 meters.
                 Customised lengths for bulk requirements provided upon request.
                             All dimensions given above are nominal.

   Pitched Roofs

             Pitched roofs clad with tiles or slates remain an extremely popular method for roofing
   many types of commercial and public building.
The flexibility offered by this system of roofing reinforces the comparatively low maintenance requirement of most
pitched roofs whilst also offering many options for creating attractive and interesting exteriors.

Many designers of commercial and public buildings (especially offices and schools) use the height offered in the pitch
of the roof to create light, attractive interiors with high level sloping ceilings which include light wells and roof
windows. The thermal efficiency required by the Building Regulations, coupled with the desire to create interesting
and attractive interiors, can make the specification of insulation for this application a complex issue.

This page and its sub-pages provide solutions for both sloping ceiling and flat ceiling applications.


Pitched roofs can be insulated to create either warm or cold roof spaces.

Insulation placed at flat ceiling level creates a cold roof space. This is the lowest cost option for insulating a roof and
uses economical readily available mineral wool quilt insulation. Very high levels of thermal insulation can be achieved
because there is virtually no restriction on the thickness of insulation that can be installed.

Insulation placed in the plane of the roof pitch creates a warm roof space. This option allows the designer to omit a
flat ceiling and use the space within the roof volume as extra accommodation enhancing the usable area of the
property without significantly altering the building envelope.

Knauf Insulation Products

                  Crown Rafter Roll 32 is a high performance roll of glass mineral wool. It is easy to cut and friction fit
                   between irregularly spaced rafters.
                  Rocksilk Pitched Roof Slab is a high density, water repellent, rock mineral wool slab specifically
                   developed for over rafter (sarking) insulation.
                  Polyfoam Sarking Board System is a high performance, 100% ozone friendly, extruded
                   polystyrene, rigid board insulation system. It is lightweight and consists of a 75mm ‘top
                  Polyfoam Raftersqueeze is a high performance, 100% ozone friendly, extruded polystyrene, rigid
                   board insulation. It consists of a flexible infill piece that fits between rafters, and allows for some
                   variation in timber rafter centres.
                  Polyfoam Pitched Roofboard is a high performance, 100% ozone friendly, extruded polystyrene,
                   rigid board insulation system. It is lightweight with shiplap edge details to sit above rafters in
                   pitched roofs.
                  Polyfoam Linerboard is a laminate of Polyfoam high performance, 100% ozone friendly, extruded
                   polystyrene, rigid board insulation and 9.5mm tapered edge plasterboard – to underdraw the
                   interior rafter line.
                  Crown Loft Roll 44 is made from glass mineral wool and formed into unfaced rolls which are
                   lightweight, flexible, resilient and non-combustible – for ceiling level insulation.
                  Knauf Breatheline is a breathable membrane with a polypropylene non-woven coating on both
                  Rocksilk Flexible Slab is a multi-purpose rock mineral wool slab that can be used in pitched roofs
                   between the rafters.

Detailed Design Considerations

Utilising the roof void
If part of the roof void is to be utilised it is most likely that insulation will be placed at rafter level. Traditionally
insulation is placed between the rafters from below, leaving an air gap between the insulation and the sarking felt for
ventilation. Finally, the ceiling is lined with a vapour control layer and plasterboard.

With the high levels of thermal performance demanded by the latest Building Regulations, it is necessary to examine
other solutions to ensure that the required performance is met at reasonable cost.

The minimum structural rafter depth, the roof pitch and the thickness of insulation needed to meet the desired thermal
performance all need to be considered in designing the roof insulation solution.
Building Regulations
Typical U-value requirements for pitched roofs is shown in the table below.

                                            U-Value (W/m2K) - Rafter Level           U-Value (W/m2K) - Ceiling Level

England, Wales & NI                                     0.20                                      0.16

Scotland                                                0.20                                      0.16

Ireland                                                 0.20                                      0.16

Controlling the condensation risk

Where insulation is placed in roofs there is a risk that condensation will form on surfaces on the cold side of the

The main way of preventing this is to install a vapour control layer on the warm side of the insulation. This limits the
amount of water vapour emitted from the building that can enter the insulation layer.

The vapour control layer must be continuous, well sealed at joints and should preferably be placed behind services,
such as electrical cables, to avoid puncturing.

Where a vapour permeable membrane, such as Knauf Breatheline, is used as the tiling underlay, any water vapour
that does pass through the insulation layer can disperse through the tiling underlay to the outside air. This is known
as a ‘Breathing’ roof and is recommended by Knauf Insulation for new buildings.

Where a traditional bitumen based sarking felt, or other impermeable underlay, is used as the tiling underlay, it is
necessary to provide cross ventilation to the cold side of the insulation to enable water vapour to dissipate to the
atmosphere and thus prevent condensation forming in the roof construction.

Building Regulations set out adequate levels of ventilation to avoid the risk of condensation within the roof space.
Approved Document F Ventilation gives specific guidance, as does Part G of the Building Standards (Scotland)
Regulations. Both allow BS 5250: 2002 to be used as an alternative.

Position of insulation
There is a choice of insulation position in pitched roofs:

                     At rafter level
                     Between the rafters
                     Above and between the rafters
                     Below and between the rafters
                     At ceiling level

Between Rafter Insulation
Insulation between the rafters can be designed in two ways:

                     ‘breathing’ roof with vapour permeable underlay as tiling underlay
                     ventilated design
Breathing roof design
Insulation fully fills the rafter space without an airspace between the insulation and tiling underlay, which must be
vapour permeable. If a thin layer of insulation is installed, it is recommended that an insulation/plasterboard laminate
is used as the internal lining to prevent thermal bridging.

A combined airtight/vapour control layer should be placed on the warm side of the insulation. This not only makes the
ceiling convection tight, but also restricts the amount of water vapour passing through the ceiling.

Where cables and piped services are to be installed, the plasterboard lining may be battened out to provide a suitable
duct. The services should be routed on the inside of the vapour control layer to avoid any puncturing.

 ‘Breathing’ Roof
 With a breathing roof, moisture vapour from the building can easily diffuse through the vapour permeable underlay, eliminating the need for cross ventilation.This has several

                           the ‘vapour open’ construction avoids the risk of condensation within the roof timbers

                           the vapour permeable underlay also acts as a windproof layer on the outside of the rafters

                           the avoidance of draughts, improves the energy efficiency of the roof construction.

 Knauf Insulation recommend the use of breathing roof construction for all pitched roofs.

Ventilated design

With this design, a 50mm ventilated airspace must be provided between the insulation and the tiling
underlay. Should the rafter depth be insufficient to accommodate both the required thickness of insulation and the
50mm ventilated airspace, an insulated dry lining is recommended. This has the added benefit of minimising thermal

Ventilation openings should be provided at each and every roof void at both low and high level. At the eaves,
ventilation openings should be equivalent to a 25mm continuous gap. At the ridge the ventilation opening should be
the equivalent of a 5mm continuous gap each side of the ridge.

A vapour control layer must be applied to the warm side of the insulation.

Insulation Below Rafters

In each case the insulation performance provided by fully filling the rafters can be improved by the use of insulated
plasterboard to the ceiling.

Over Rafter Insulation

Insulation over the rafters provides a completely insulated external envelope to the roof construction, and allows the
maximum usable space within the roof enclosure.

The insulation boards are laid over the rafters. It is important that there should be no gaps in the insulation layer and
no ventilation between the outside and the roof space. A vapour permeable underlay must be provided to direct wind
driven rain and snow to the gutter.

Counterbattens are fixed through the insulation boards and vapour permeable underlay into the rafters. Where the
over rafter insulation is over 50mm thick, consideration should be given to the fixing of the counter battens.

Further insulation will be required between rafters to meet Building Regulation requirements. If the insulation board
over the rafters has a high vapour resistance, the use of mineral wool between the rafters is not recommended unless
the designer is confident that an effective vapour control layer can be provided to the underside of the rafters.

Where only rigid insulation boards with a high vapour resistance are used, such as extruded polystyrene, a vapour
control membrane is not normally required unless the building is liable to high humidity. An airspace is not required
between the insulation and tiling underlay if the latter is a vapour permeable underlay.

The rafters should be faced with 12.5mm plasterboard, or similar, to provide fire protection.

Ceiling Level Insulation

This is the most common and economic way to insulate a pitched roof and creates a ‘cold roof’. It has the advantage
of minimising both the heated volume and the quantity of insulation material needed.

Cold ‘breathing’ roof

The features of a cold breathing roof are:

                  a vapour control layer at ceiling level to limit the amount of water vapour entering the roof void
                  a vapour permeable underlay as the roof underlay, to allow dissipation of water vapour from the
                   roof void and, just as importantly, to act as a windproof layer
                  25mm deep counterbattens to provide an airspace above the vapour permeable underlay for
                   dissipation of moisture vapour
                  ceiling level insulation that is pushed up tight against the vapour permeable underlay to prevent air
                   leakage into the roof void at eaves level Insulation is laid at ceiling level in two layers, the first layer
                   between the joists and the second layer across the joists.

Cold ventilated roof

With the ventilated design, the insulation is also placed at ceiling level, but cross ventilation of the roof void is used to
disperse moisture vapour.

It is important to allow a clear, unobstructed ventilation path between the insulation and the tiling underlay to allow
outside air to enter the roof void and prevent the build-up of moisture.

The ventilation requirements for roofs with a double pitch are shown above. Lean-to and mono-pitch roofs should
have a continuous gap equivalent to 10mm at the eaves and high level or ridge ventilation equivalent to a continuous
gap of 5mm.

Ventilation openings should prevent the entry of insects. A 3mm or 4mm mesh across the ventilation holes should be
incorporated. A separate vapour control layer is not necessary, but all gaps and holes in the ceiling should be sealed
to restrict the amount of water vapour that enters the roof void.
Cold Roof – Other Precautions

All tanks and pipes in the roof void should also be insulated to prevent freezing. Tank insulation jackets should meet
the standards in BS 5422: 2001. Do not insulate directly under the cold water tank.

The roof access hatch should also be insulated to a minimum depth of 50mm and draught stripped. Provide catches
or bolts to compress the draft seal and prevent air leakage from wind uplift.

Upgrading an Existing Pitched Roof

An overall insulation thickness of 250mm to 300mm of mineral wool is recommended when upgrading the thermal
insulation of an existing roof.

In most pitched roofs, any existing insulation is likely to be between the ceiling joists. Where the existing insulation
reaches the top of the joists, the new insulation should simply be laid across the joists at right angles. Where the
existing insulation is below the joist height, add extra insulation between the joists so that it reaches the top of the
joists. Then lay a second layer at right angles to the joists.

Existing roofs are most likely to have an impervious sarking underlay, such as a bitumen felt, so it is very important to
maintain the cross ventilation of the roof void from eaves to eaves.

Thermal Bridges
To avoid thermal bridging, the roof insulation should butt up to or lap the wall insulation. The designer should
consider at what stage this ‘linking’ insulation is installed, as this will affect the detailing of insulation at the eaves.

In cold roofs, one way of achieving this in practice is to place a short length of insulation quilt over the wall plate (and
cavity closer, where applicable) immediately before the tiling underlay is fixed. This avoids having to push the
insulation into place from inside the roof once the roof covering has been completed.

The gap between gable/separating walls and the first joist/rafter should be insulated to avoid thermal bridging. In cold
roofs, the second layer of insulation should be butted up against the gable and separating walls to avoid thermal

Knauf Insulation products are supplied in widths to suit standard joist/rafter spacings.

Recessed Light Fittings

Where recessed light fittings are to be used, specify ones with compact fluorescent or low voltage tungsten lamps to
minimise heat build up. Locate the fittings in enclosures that provide at least 75mm clearance around the fitting for air
to circulate. Seal the enclosure to prevent air leakage into the roof void and, if necessary, ventilate to the room.


Contractors should follow the guidance given in HSE 33 when using and installing fragile materials.

Typical Details: Warm 'Breathing' Roof
Typical Specification Clauses

1) Mineral wool between rafters

The whole area of the pitched roof to be insulated with Crown Rafter Roll 32 thick, in two layers, friction fitted
between the rafters. The insulation to be pushed over the wall plate at the eaves to link up with the wall insulation.

A minimum 50mm airpath must be maintained between the insulation and the sarking felt.

Alternatively, refer to NBS clauses: P10/140 and 320

2a) Insulation between rafters with Crown Rafter Roll 32

The whole area of the pitched roof to be insulated with Crown Rafter Roll 32, thick, friction fitted between the
rafters. The width of the insulation should be appropriate to the spacing of the rafters.

Polyfoam Linerboard of thickness with integral 9.5mm plasterboard nailed to the rafters at maximum 300mm
centres and finished using standard drylining techniques.

Alternatively, refer to NBS clauses: P10/140 and 320, and K10/245

2b)Insulation between rafters with Rocksilk Flexible Slab

The whole area of the pitched roof to be insulated with Rocksilk Flexible Slab thick, friction fitted between the

Polyfoam Linerboard of thickness with integral 9.5mm plasterboard nailed to the rafters at maximum 300mm
centres and finished using standard drylining techniques.

Alternatively, refer to NBS clauses: P10/140 and 320, and K10/245

3a) Rocksilk Pitched Roof Slab and Crown Rafter Roll 32

Insulation laid over rafters to be Rocksilk Pitched Roof Slab, thick, located over the rafter. All boards tightly
butted and with staggered joints. Knauf Breatheline is then pulled taught and laid directly over the insulation and held
in place by 50 x 32mm counter battens nailed through the slabs, into the rafters. The tiling battens to be nailed into
the counter battens.

Crown Rafter Roll 32 thick, to be friction fitted between the rafters. The width of the insulation to be cut from
the roll to suit the spacing of the rafters.

Alternatively, refer to NBS clauses: K11/670 and P10/140 and 320

3b) Polyfoam Sarking Board System

Insulation laid over rafters to be Polyfoam Sarking Board, thick, located over the rafter via the rebated edges.
Knauf Breatheline is then pulled taught and laid directly over the insulation and held in place by 50 x 32mm counter
battens nailed through the boards, into the rafters. The tiling battens to be nailed into the counter battens.

Alternatively, refer to NBS clauses: K11/670 and P10/140 and 320

3c) Polyfoam Pitched Roofboard and Polyfoam Raftersqueeze

Insulation laid over rafters to be Polyfoam Pitched Roofboard, thick, located over the rafter. Knauf Breatheline
is then pulled taught and laid directly over the insulation and held in place by 50 x 32mm counter battens nailed
through the boards, into the rafters. The tiling battens to be nailed into the counter battens.
Insulation between the rafters to be Polyfoam Raftersqueeze, supported on battens nailed to the side of the rafters,
where required.

Alternatively, refer to NBS clause: K11/670 and P10/140 and 320

4a) Ventilated cold roof

The whole area of the ceiling to be insulated with two layers of Crown Loft Roll of total thickness Width of
first layer of insulation to be appropriate to the joist spacings and of a thickness equal to joist depth. The insulation to
be laid between the joists and to finish over wall plate on external walls. The second layer to be laid at right angles to
the first layer. All joints between the rolls of insulation to be close butted.

Maintain an airspace between insulation and sarking felt/sarking board at the eaves.

Do not insulate under cold water tanks. Cold water tanks and pipes to be insulated separately.

Loft hatch to be insulated with a minimum 100mm depth of insulation.

Alternatively, refer to NBS clauses: P10/120 and 130

4b) Cold Breathing Roof

The whole area of the ceiling to be insulated with two layers of Crown Loft Roll of total thickness Width of
first layer of insulation to be appropriate to the joist spacings and of a thickness equal to joist depth. The insulation to
be laid between the joists and to finish over wall plate on external walls and pushed up tight to Knauf Breatheline. The
second layer of Crown Loft Roll to be laid at right angles to the first layer.

All joints between the rolls of insulation to be close butted.

Do not insulate under cold water tanks. Cold water tanks and pipes to be insulated separately.

Loft hatch to be insulated with a minimum 100mm depth of insulation.

Alternatively, refer to NBS clauses: P10/120, 130 and 320

4c) Upgrading Existing Insulation

The two alternative specifications:

a) Between joists (where applicable)

The whole area of the existing ceiling to be insulated with Crown Loft Roll, thickness Insulation of width
appropriate to the joist spacings to laid over the existing loft insulation and dressed over wall plate.

b) Across the joists

The whole area of the existing ceiling to be insulated with Crown Loft Roll, thickness To be laid over the
joists, with all lateral joints close butted.

For both methods all joints to be close butted. Maintain airspace between insulation and sarking felt/sarking board at

Do not insulate under cold water tanks. Cold water tanks and pipes to be insulated separately.

Loft hatch to be insulated with a minimum 100mm depth of insulation.

Alternatively, refer to NBS clause: P10/120 and 130
4d) Cold roof with storage deck

The whole area of the ceiling to be insulated with Crown Loft Roll. Width of Crown Loft Roll to be appropriate to the
joist spacings and of a thickness equal to joist depth. The insulation to be laid between the joists and to finish over
wall plate on external walls and pushed up tight to Knauf Breatheline.

Polyfoam Supadeck Total, thickness to be laid over the Crown Loft Roll at right angles to the ceiling joists.
Begin laying along the full length of one edge of the storage deck. Fix each Polyfoam Supadeck Total board to the
ceiling joist below in the centre using a 5mm x 150mm screw fixing. All chipboard joints to be glued.

Any gaps between the edge of the Polyfoam Supadeck Total and the Knauf Breatheline to be filled with Crown Loft

 We have seen a lot of changes in the flat roofing industry over the past two decades
   and have gained much knowledge and expertise. We have used this knowledge to
  bring you the best roofing systems ever designed and manufactured for your flat or
low pitched roofs. Our specialty being flat and low pitch roofs has perfected our skills
     in this area providing the customer with the best materials and quality service.

 Lifetime Roofing Systems is proud to say that in the many years of being in business
   we have had positive customer feed back with no roof failures. Lifetime Roofing
Systems has roofs over 14 years old in this area still performing great for their owners.
 Our effort to stay on the cutting edge of technology of Single-Ply membrane roofing
   systems has affiliated us with the forerunner in the single membrane market. IB
                  Roofing Systems(Industries Best Roofing Systems).

  Our supplier, IB Roof Systems has also been a pioneer in the flat roofing industry.
They were the first to have a lifetime residential warranty. They have set the standard
 in the restaurant roofing market in producing the first membrane to be designed with
      containment liner industry standards. Our ChemGuard roofing membrane is
    compatible with every restaurant roof and has incredible chemical resistance for
 industrial applications. Traditions shingle stylistic roofing membrane is the first low
  pitch residential application with lifetime warranty. Our Deckshield'membrane has
proven it's long-lasting beauty and durability providing a walkable water tight solution
                                         for decks.

  We cut our teeth in the mobile home market in the late seventies using new acrylics
   quickly converting over to IB's single-ply membrane giving our homeowners a
                           lifetime solution to problem roofs.

So, when you're ready, we'll be happy to assist you. If you have any questions, please
                    don't hesitate to give us a call or e-mail us.
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Roof Flashing Done Right
If you're collecting dripping water in a pot beneath your roof, you may want to inspect
the roof flashing. Anywhere surfaces intersect on a roof is a prime spot for water
seepage. Flashing provides the extra protection these spots need. These problem
areas include the edges of skylights and chimneys, soil stacks, vent fans and roof
valleys, as well as the intersection of the roof deck and dormer walls.

Most flashing is made of galvanized metal, but DIY'ers may prefer aluminum flashing
because it's easier to bend. Most flashing products are designed for easy installation,
and if the material is installed correctly, then your roof shouldn't leak. However, from
time to time, the nails that fasten flashing work loose, or the flashing material pulls
away from seams and joints and requires maintenance. Here's a look at some
general principles of roof flashing that will help guide you through a proper repair or
replacement—or even new construction.
A Look at Roof Design
All roofing systems are made of a number of different components: roof sheathing,
underlayment, roofing material, roof intersections, flashing details and ventilation.
Each of these systems must be installed correctly for the system to work as

Common pitched roof systems rely on the force of gravity and the surface friction of
the roofing materials to direct the flow of water downward and outward. These
systems rely on overlapping elements—roofing felts, shingles, tiles and flashing
details—to redirect the rainfall. The pitch of the roof provides the gravity and the
detailing provides the redirection.

However, in low-slope roofing systems it is easier for water to accumulate. The force
of gravity drives the water into every imperfection in the waterproofing system. So, for
low-slope roofs, water is kept outside the building envelope by providing a perfect
waterproofing barrier over the entire roof system and around every penetration in that

Roof sheathing is attached to the roof framing, trusses or rafters, and provides the
nail base for the other components of the roof system.

Next, roofing underlayment, often made of building paper or “felt,” is installed as the
first weatherproofing layer for a pitched roof. Underlayment should be installed from
the bottom of the pitched roof to the top, such that each upper layer overlaps the
lower layer. This method of installation channels the water out and down, away from
the wood-panel sheathing below.

Finally, roofing material, the visible finished layer on a roof, provides the primary
waterproof barrier for the structure. For pitched roofs, almost all roofing materials rely
on some form of shingling to provide the weatherproof barrier. Like the underlayment,
these roofs are installed from the bottom-up, with successive layers overlapping both
vertically and horizontally to shed away water. Low-slope roofs can use many
different proprietary and non-proprietary systems to form their waterproof barrier,
from single to multiple-ply; adhered, mechanically anchored or ballusted; hot mopped
or cold applied (solvent, urethane or epoxy-based).

Flashing works in conjunction with all of these elements to reinforce the
waterproofing at roof intersections or penetrations.

Closer Look at Flashing
For pitched roofs regardless of the application or type of flashing used, the purpose
of flashing is to direct the flow of water that leaks into the intersection down and away
from the interior of the structure to the topside of the roofing material. In every case,
the top edge of the flashing passes underneath the underlayment, the upper pieces
of flashing pass over the lower pieces, and the lower edge of the flashing always
passes over the top of the roofing material. In such a manner, the flashing never
directs the flow of water to the bottom side of the underlayment, never putting it in
contact with the wood structural panel sheathing.

Valley flashing protects the valleys where two roof planes meet. This material is
available with a V- or W-shaped profile and is placed over the top of the building felt
before the roof's finishing material is installed.

Step flashing protects the joints between the roof deck and chimneys or dormers.
Step flashing fits to each course of shingles and appears to “step” up the wall of the

Vent pipe flashing fits over flues or pipes. The shape of vent flashing is typically a
cylinder with a wide flange at the base, which is lapped into the shingles as the
roofing is installed.

Drip edges are strips of flashing material that run along roof eaves and rakes to
prevent water from seeping under the finished roof along its edges.

The majority of roof leaks occur in locations where the plane of the roof is interrupted
by a ridge, another roof intersecting at an angle, a wall or penetration. Even the
simplest of rooflines has dozens of potential leaks sites due to chimneys, ridges,
valleys, etc. Proper detailing around these areas, as detailed in the diagrams, is
critical to prevent these leaks.

Metal flashing material is generally soldered or brazed. Similar towelding, the brazing
process bonds two pieces of metal into one single piece. In many cases, flashing
components have to wrap around corners or be spliced together, and in these cases
they can be soldered or brazed to ensure a strong, durable joint.

Also, remember that both temperature and humidity can cause roofing materials
(shingles, wood sheathing, flashing) to expand and contract with seasonal changes.
The flashing materials will continue to be leak-proof if they can withstand this
movement of the roofing materials. Well engineered and properly installed two-part
flashing can handle this movement with no problem. Two-part flashing systems
consist of a base flashing—often step-flashing—that is laced into the finished roof
material. The base is then covered by another metal flashing piece lapped over it.
The second piece should not be fastened to the base, so the two pieces can move
against each other independently when the roofing materials shift with seasonal
Attention to Detail
Keep in mind that flashing details are a very technical aspect of roof construction,
and this type of work is best left to experienced professionals. Soldering vertical
surfaces requires skill, and you don't want to gamble with the integrity of your roof.
The best way to learn proper flashing techniques is to spend time with an
experienced craftsman as he installs a complete roof.
That being said, here are a couple of flashing tips that even an inexperienced
homeowner should make note of. Always check the roof flashing and the condition of
the shingles whenever you clean your gutters. Look for loose nails and any damage
to the seals at the edges of the flashing. Roofing cement can dry out and crumble
away, exposing joints to water. Fasten loose nails and cover exposed nail heads with
roofing cement. Renew flashing seals by chipping out old caulking and mortar along
the edges of the flashing. Recaulk the joints between the roof and the flashing. It's
much easier to reseal the flashing than it is to patch a water-stained wall or ceiling.

Badly corroded flashing will need to be replaced. To do this, you will also have to
remove several rows of shingles as well as the old flashing. Then replace and fasten
the flashing, and reinstall the shingles with the proper overlapping procedure.

Also, new flashing can be exceptionally shiny, especially in contrast to the earthy
brick walls of many homes. You may want to paint the flashing to match the roof.
First use a stiff wire brush and solvent to clean the surface of any dirt, debris or
corrosion (keep solvent away from asphalt shingles). Coat the flashing with a zinc-
based primer followed by two or more coats of spray-on, rust-preventive metal paint.

Editor's Note: This article appears courtesy of APA – The Engineered Wood
Association. Check out more of APA's building tutorials at
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Roofing Revisited
Monte Burch

If you own a home long enough, sooner or later you1ll have to consider reroofing. If you suspect
problems, make a thorough inspection of your roof. Asphalt or composition shingles will usually last
from 20 to 40 years, depending on local climate, the quality of the shingles, quality of installation and
with regular maintenance. If your roof is over 20 years old, it should be inspected yearly. Overall age
is a good indicator of whether or not reroofing is needed. Several signs can also indicate deterioration
and forthcoming problems. Incidentally, when purchasing a home, a roof inspection is one of the most
important things you can do.

The first sign of deterioration is obvious -- a leak. If you find one leak, or even two, in a specific
location sometimes you can patch the roof or re-gutter to prevent ice dams to solve the problem.
Leaks, indicated by water stains in the house, wet areas under the roof deck or in the attic spaces, are
a sign of serious roof problems, and you1ll probably have to reroof.

If you find excessive amounts of the tiny protective mineral granules, which normally cover the
shingles, in gutters or beneath the downspouts, this normally indicates excessive weathering. Also,
black spots in the roof indicate loss of the granules.

As shingles age, they tend to curl up and crack, especially on the Southern and Western exposures
where they get the most ultraviolet rays. This causes the shingles to lose their water resistance and
creates openings where water can leak through.

Another important sign is missing shingles. If only one or two shingles are missing, you can often
simply repair or replace. Numerous missing shingles, however, means you1ll probably have to reroof.
And, of course, after a major wind or hail storm you will probably have to consider reroofing.

Walking on a roof can be dangerous, even when doing the roof inspection. Take extra care. If
possible, make the inspection from the ground, using binoculars to examine the shingles and their

Removing Old Shingles
The next step is to determine if you will be able to re-cover existing shingles, placing a new roof over
the old shingles, or if the old shingles will have to be removed. The latter is called a 3tear-off2 job by
professionals. In many instances, new asphalt shingles may be applied over old asphalt shingles, roll
roofing and wood shingles. New shingles cannot be applied over slate or wood shake shingles.

The decking should also be solid enough to provide good anchorage for the roofing nails. The nails
must completely penetrate 5/8-inch sheathing and go at least 3/4-inch into solid decking. In some
cases, the old decking may be strips with openings between and should be replaced. If the existing
deck is in good shape, the old shingles are not excessively warped or curled and there aren1t too
many layers of existing shingles, you can usually leave the old shingles in place. Local building codes
may also restrict the number of layers that can be applied before it is mandatory to tear off the old
shingles. You should also consider whether the decking is strong enough to hold the new shingles and
the weight of the workers. In most instances it is best that roofing layers be limited to two; in other
words, you can usually reroof once before tearing off.

Do-It-Yourself or Pro
The next step is to determine if you can do the job yourself. Reroofing is hard work, and it can be
extremely hazardous, especially reshingling a multiple story house and/or a house with steep roof
pitches. The latter requires special scaffolding that you will need to rent or purchase. If you1re not
afraid of heights, or hard work, the techniques needed for reroofing are not especially difficult. And,
you can save approximately 50 percent of the cost of reroofing by doing the job yourself.

For steep pitches you1ll need scaffolding, ladder hooks or jacks and ropes. You should also have
tarps to cover the roof in case of inclement weather. Then watch the weather. In addition to a means
of nailing down the shingles, youŒll need a good utility knife, a heavy sheath, straight edge and chalk
line. Always cut from the back side of the shingle as this doesn1t dull the blade as does cutting
through the granules on the front. A flat shovel, pry bar and claw hammer are needed for tear-off jobs.

Shingles can be applied with roofing nails and a hammer. A pancake type air compressor and a coil
roofing nailer makes the job easier and quicker, even for a first timer. These tools can often be rented
along with the other specialty tools required, but you should figure in this cost when determining
whether you want to do the job yourself or contract it. Don1t forget to add in the cost of hauling off and
dumping the old shingles for tear-off jobs.

Selecting Shingles
Composition asphalt shingles are used on the majority of houses in the United States. Compared to
other products, they are the most practical and are priced reasonably. For the most part, they can be
expected to last between 20 and 40 years. This article relates primarily to reroofing with asphalt
shingles. Several considerations should be made when reroofing, and the first is color. Shingles are
available in a wide array of colors. It1s a good idea for the shingles to match or harmonize with the
exterior color of the home. Darker colors are more popular in colder climates, while lighter colors are
more popular in warm sunny climates. In both instances these colors can result in energy savings.
Light colors tend to make a small house look larger, dark colors can make a large house look smaller.
It's also a good idea to keep a general color scheme that matches your neighborhood.

According to the Asphalt Roofing Manufacturers Association (ARMA), the typical roof shingle has
undergone some dramatic advances in recent years. A wide variety of shingles can be found with a
variety of colors, styles, sizes and incorporating unique performance and architectural features. For
instance, the demand for fire-resistant shingles has grown dramatically in recent years, especially in
the brush fire-prone areas of the West and Southwest. In high-wind and hurricane areas, special wind-
resistant shingles can provide additional protection for a home1s roof, and by extension, its contents.
Impact resistant shingles may be considered in areas where hail damage is a concern. In the warm,
humid areas of the United States, algae-resistant shingles can help homeowners protect their roofs
against shingle discoloration.

Three-tab shingles are the most common and most economical. The waterline created in their
installation can, however, eventually become eroded. One of the more popular shingle styles these
days is the laminated shingle, which is manufactured with one or more layers of 3tabs2 or laminated
cutouts to create additional thickness to the shingle or a solid surface. With their shadowing effects,
laminated shingles give a visual depth and a custom look to a roof. Because there is no waterline, as
on three-tab shingles, the laminated shingles also tend to last longer. Local building codes may
specify the rating of the shingles that can be used in your area.
Except for mansard roofs, most composition shingles are held in place with four fasteners.


Shingles are estimated in squares. One square of roofing shingles covers 100-square feet of roof.
Shingles come in packages to make up one square. The number of packages needed for a square
depends on the type of shingle and the number of shingles in the package. Shingles are also
measured by their weight, with the heavier and more durable shingles, weighing 235 pounds, common
for most roofing applications. This means a square of shingles weighs 235 pounds. When ordering
shingles, simply measure the square footage of the entire roof and divide by 100 to determine the
number of squares needed. Add about 5 to 10 percent for starter courses, ridge caps and waste.

The old shingles are first removed with a wide, flat shovel, using a claw hammer and pry bar to loosen
stubborn nails. Use the pry bar to loosen and remove the flashing around the soil stacks and vents.
Tear-off creates a large amount of debris. As you go, continue to sweep the debris off. Loose debris
causes a hazard, especially on a steep roof. You should also have some method of collecting the
debris and preventing it from damaging shrubs or flowers planted near the house. And, when you
finish the tear-off, you must have some place to dispose of the debris, and there will be a lot of it.

Once the old shingles and asphalt paper covering the deck have been removed, carefully inspect the
decking for rotting or holes and replace any defective decking. Small holes can be patched over with
pieces of flashing. Make sure all nails have been removed from the decking.

For roofs with a pitch of 4-inches or better, a layer of No. 15 asphalt-saturated felt should be applied.
Begin at the bottom edge of the roof, and overlap each course 2-inches over the lower layer. Roofing
felt has lines printed on it to help lay straight courses. The felt should be lapped 6-inches from both
sides of hips and ridges. Nail the felt every 2-inches along the outside edges. New drip edge should
be applied on all edges.

Shingling Basics
Before you start the job, thoroughly inspect and repair or replace any rotting wooden trim, soffit and
guttering. Don't reroof, especially with a tear-off, unless there is no forecast of rain within the next 72
hours. If the shingles are to be applied over existing shingles make sure you nail down any loose
shingles or replace those that are missing to create a smooth surface. Drive down all loose or
protruding nails. Nail down the pieces of split or curled shingles. Replace all worn edging or drip cap
with new. Again, before beginning the reroofing sweep all debris from the surface.

At this point the tactics are the same, regardless of whether applying over decking or existing
shingles. Most shingle bundles or packages come with specific instructions for application.

If at all possible have the roofing dealer place the shingle bundles on the roof so you don1t have to
carry all the shingles up a ladder. This is not only dangerous, but extremely hard work. Most roofing
dealers will place the shingles on the roof at no extra cost.

A starter course of shingles is first installed along the bottom edge of the roof. This is done by first
cutting the tabs off shingles, and applying the course upside down or with the uncut edge on the
bottom roof edge and just flush with the edge of the drip cap or metal strip. Some installers use a full
width shingle for the starter course. Before beginning, cut 3-inches off the side of the first shingle. This
prevents the cutouts in the next course of shingles from matching those of the starter course.

Regardless of whether on bare decking or old shingles, the fist step is to lay a starter course. This
may consist of half shingles or whole shingles with the tabs laid up. If on bare decking, asphalt roll
roofing must first be applied. New drip edge is always installed all around the decking.

Begin the first course with a full shingle. If applying over existing shingles, the top edge of the shingle
should line up with the butt edge of the old shingle in the course above. If needed, trim the shingle to
fit. This is called "butt-and-run" and can only be done if the existing shingle runs are straight. If the
existing shingle runs are not straight, you will have to first snap a straight line.

Fasten the shingles in place on the nailing indicators. On three-tab shingles, remove half a tab, or
one-sixth of the shingle from the outside edge of another shingle and fasten it above the first course to
create the second course. Then cut a full tab from a shingle and lay it to begin the third course. The
fourth course begins with a tab and a half off. The fifth course is a full shingle, in the same manner as
the first course. Then repeat the pattern going up the rake. It1s best to work upward in a triangular
fashion moving up and across at the same time rather than laying one single course, then another
single course, then another the entire length of the roof. This method means you don1t have to move
around as much, and creates less noticeable difference if there is some package color differences in
the shingles. Professional roofers don't cut the beginning shingles, they simply let the shingles
overhang the edge, then cut away when they finish the edge.

Another shingling pattern may also be used. It's more work at first, but creates a fast method once
started. In this case each course is cut in increasing sixths to create the four courses.

Installation of laminated shingles is different. Because there basically is no tab to locate cuts, most
professionals install them with a 7- to 8-inch gauge.
Because there are no tabs to gauge the cuts, laminated shingles are cut and laid on a 7- to 8-inch
gauge. Shown is a typical example, but because the design of the laminate can be different, it's
important to follow the gauge specified by the manufacturer.

Make sure you align each shingle carefully, following manufacturers exposure specifications. In most
instances this means the butt edge of the tabs align with the top of the cutouts in the course below.
Fasten with four nails per shingle, making sure the nails are driven straight and not angled where they
can cut into the shingle.

It's also best to begin the shingling job at the rake that is the most visible, and work toward the rake
that is less visible.

Remove the old ridge cap before you bring the courses up to the ridge. You can purchase special
ridge cap shingles or simply cut three-tab shingles in thirds. Laminate shingles require special ridge
cap shingles. Begin by bending a cap piece over the ridge and along the centerline of the shingle. If
the weather is cold then take the pieces inside to warm them. Fasten in place with a nail on each side
5 1/2 inches from the exposed end, and 1 inch up from the shingle edge. The next shingle should
overlap to create a 5-inch exposure. Lay the laps away from the prevailing wind direction.

Valleys may be flashed and the shingles cut in a straight line along the valley edge, or the valleys may
be laced. Although lacing is a bit more complicated, it provides a tighter, more sturdy and less leak-
prone roof. Lacing is the most common these days and is the most popular with the experts. To lace a
valley the shingles are interlaced as the course goes up the valley, creating a solid, shingled surface.

Most valleys are laced these days, interlacing the shingles. The outer layer is then cut on a sraight line
through the centerline of the valley.

And remember: Don't attempt to shingle in extremely cold or extremely hot weather. In cold weather
the shingles can break, and in hot weather you can mark and scar shingles with your feet.

Editor's note: For more information, check out the ARMA web site at
(1) Building a Patio Cover
No special tools or skills are needed. Just keep in mind common dimension lumber and standard
size panels when laying out your design.

                      (1) Post foots should be approximately 14" deep and 12" across. Set 8" x 3/8"
                      bolt about 3" deep into poured concrete for post anchors. Wood posts may also
                      be secured with 4" angle brackets. Attach 2" x 6" rafter hangers to header, then
                      attach header to house studs with lag screws.

                      (2) Drill posts and set on pins. Toenail crossbeam to post. NOTE: allow 7' 4"
                      from floor to bottom of front header for best ventilation.

                      (3) Pre-notch rafters to compensate for slope. Allow a 1" minimum pitch per
                      foot for adequate drainage.

                      (4) Attach rafters to header and crossbeam with 1" screws and nails.

                      (5) For ease of installation and an attractive design, nail crossbraces between
                      rafters using alternate spacing. Nail round and corrugated molding strips to
                      framing, then paint or stain wood before installing panels.

                      (6) Lay panels on rafters with one corrugation overlap and fasten with
                      aluminum screw nails. Holes should be predrilled. Attach flashing at same time.

                              Patio Cover Materials List
                    Corrugated Panels
                                         4-26" x 10'   5-26" x 10'    6-26" x 10'
                    Wood Filler Strips
                                          5 strips       6 strips       6 strips
                                         4 flashing     5 flashing     6 flashing
                                          2 boxes        2 boxes        3 boxes
                                          4 tubes        5 tubes        5 tubes
(2) Building A Greenhouse
Find a spot that will give your greenhouse maximum sunshine. Have water handy for sprinkling
plants. Plan to
install fans if you intend to use the greenhouse year-round. Gas and electrical connections should
also be considered.

   1. Lay patio block for a portable greenhouse or pour concrete footers for a permanent
      installation. Cut 2 x 4s to
      proper lengths and nail studs every 24" on center to form front, back and side framing.
   2. Nail back and front framework to side frames.
   3. Pre-cut roof rafters to desired pitch and nail into position.
   4. Pre-drill holes and fasten side panels. Use aluminum nails with neoprene washers and
      apply mastic to overlap of one corrugation.
   5. Overlap roof panels one corrugation (away from prevailing wind) and nail to rafters,
      starting from one end.
   6. Adjust door construction to desired size.
   7. Install vent as close to roof peak as possible.
   8. Apply front and back panels similarly to side walls. Cut to fit pitch of roof and around
   9. Nail trim limber to all corners and to front and back where panels meet roof.

Some additional considerations for this project...

      Fasten aluminum ridge roll flashing to each panel as you proceed.
      Adjust door construction to desired size.
      Install vent as close to roof peak as possible.
      Apply front and back panels similarly to side walls. Cut to fit pitch of roof and around
       vent. Nail trim lumber to all corners and to front and back where panels meet roof.

General Information About Corrugated Panels...
Panels install easily with ordinary tools and may be drilled, sawed, punched, or nailed without
damage. The material is durable, rot-proof, waterproof, and is not harmed by ordinary cleaning
solutions. Sequentia Corrugated panels that are reinforced with gloss fibers (FRP, fiberglass
reinforced panels) will expand and contract up to three times less than PVC and polycarbonate
panels which provides for a more stable product in both hot and cold conditions. Panels install
much like corrugated metal and provide the added benefit of light transmission.

Polycarbonate panels contain a translucent UV resistant film on only one side of each panel.
Each polycarbonate panel is imprinted with the following: “THIS SIDE OUT”. The side of the
panel with this information should be installed toward the sun or exterior of the structure it is
being used on. The other side of the panel has little UV resistance and will be damaged by the
harmful rays of the sun. Polycarbonate panels are not recommended as exterior privacy walls
(which are installed vertically vs. horizontally) because both sides of the panel can receive direct
exposure to the sun hence, damaging the panel.
The following date is based upon uniform loading of corrugated panels fastened as
recommended and with a safety factor of 2.5.
In heavy snow areas, 500 Series (or greater) panels are recommended and closer spacing of
purlins should be considered. While panels may not fail under heavy snow loads, strain at
fastening points can cause slight cracking.

1. Table is based on section properties or actual load tests (available upon request).
2. Design loads are governed by local building codes. Consult code authorities for specific loads
and stresses.
3. Information is provided as preliminary data for designers. It should be checked and verified
for use with a duly license engineer or architect.

UNDER NO CIRCUMSTANCES should panels be allowed to support undistributed loads
  such as the weight of a human body. Use only approved roof ladders and planking.

RECOMMENDED OVERLAP: (2.67" x 9/16") Overlaps shown will provide best protection
against leakage and air infiltration. Vinyl lap seal and/or mastic must also be used to achieve
effective seal on side-laps and end-laps.

                                          52-5/8" Width

                                        26", 50-1/2" Width

                                          51-1/3" Width

MINIMUM BEND RADIUS: (2.67" x 9/16") Flexing the panel to the point of buckling can
cause fracture and rapid deterioration at the fracture point. Install at ambient temperatures not
below 60°F.

TYPICAL FASTENERS include weatherproof nails or wood screws with Neoprene washers,
self-tapping screws and grommet type fasteners. Fastener selection is dependent upon type of
corrugation and understructure material. Panels should be pre-drilled a minimum of 1/16" larger
than fastener diameter.

1. #10 x 1-3/4" Aluminum round head wood screw with armored Neoprene washer.
2. #10 x 1" Aluminum round head wood screw with 1/2" armored Neoprene washer.
3. 1-3/4" x .145" Aluminum roof helix nail with Neoprene washer.

These instructions are intended as guidelines for proper installation procedures. In the use of
tools, fasteners, sealants, and adhesives, follow manufacturer's recommended procedures.

USE APPROPRIATE SAFETY EQUIPMENT such as safety glasses and filter masks when
cutting or drilling. DO NOT WALK ON PANELS. Observe simple fire precautions. Similar to
wood of equal thickness, fiberglass panels can be flash-ignited at approximately 700°F.

While a single panel easily withstands exposure to sunlight and the elements, a stack of
fiberglass panels will trap heat and moisture causing clouding to the panels. To avoid this
irreversible effect, panels should be stored in a dry, shaded, well-ventilated area. Store panels on
edge or on end. Skids should be elevated at one end with wood spacers.

Provide purlin member at recommended maximum intervals required for corrugation selected.
See LOAD/SPAN CHART on first column.

Cut fiberglass, PVC, and Polycarbonate panels using hand or power saws. Saw blade should be
fine-toothed carbide tipped, or safety fabric reinforced abrasive disc. Face shields and
appropriate safety equipment should be worn.

All panels should be pre-drilled not less than 1-1/2" from panel ends and holes drilled a
minimum of 1/16" larger for fiberglass panels and 1/8" larger for PVC and Polycarbonate panels
than the fastener diameter. Panels may be drilled singly or several at a time.

For best protection against prevailing winds and weather, install panels beginning at leeward end
of run and work to windward. See RECOMMENDED OVERLAP drawing at bottom of first
1. Provide a minimum of one corrugation overlap at sides.
2. Provide 8" end-lap for roof with pitch of less than 4" in 12"; 6" end-laps for pitches or more
than 4" in 12".
3. Fasten panels through crowns at every second corrugation. Fasteners with armored Neoprene
washers are recommended. Space fasteners 6" to 8" on center at panel ends: 12" to 16" on center
for intermediate purlins and siding applications.

1. To avoid deflection of panels, tighten screws until washers will not rotate, then tighten one
more turn.
2. Avoid excess burrs on drilled or punched holes to protect Neoprene sealing face.
3. Drill for and fasten extreme bolts, with full support below all valleys, then drill for and fasten
in-between points.

Panels may we washed either mild detergent-type cleaners or by steam and high pressure spray
systems. Apply cleaners with sponge or soft brush and rinse thoroughly in cold water to
eliminate cleaning agent film build-up. Always follow cleaning agent manufacturer's
instructions. Test small area before applying over entire surface. Hard water deposits may be
removed with a 10% solution of acetic acid in COLD water. Rinse thoroughly.

Thanks again to the Kemlite Company for allowing us to reprint these installation
instructions for their high quality Sequentia Corrugated Roof Panels.

        Lecture Five

        Bas ic Terminology:

        1) Roof: the enti re covering as s embly
        2) Roofing: that part o f the roo f which is expos ed to the elements .
        3) Pitch: ris e over run
        4) Subs trate: the deckin g that carr ies the roofing material.
        5) Eaves : roo f overhangs
        6) Ridge: the peak of t w o or mo re roo f s lopes
        7) Valley: an invers e rid ge
        8) Ceiling: the finis h material at tached to the unders ide of the roo f.
Bas ic types of roof des igns :

1) Flat: m us t have a s light s lope for d rainage
2) Shed: a s ingle s lope
3) Gable: two s lopes meeting at a rid ge. Two walls extend up t o the ridge.
4) Hip: two gables , a pyra mid could be cons idered a hip roof.
5) Gambrel: four s lopes in one di rection, the typ ical barn roo f.
6) M ans ard: two gambrels . Bas ically is to the gambrel w hat the hip is to to gable.

Roof s tructure:
Depending on the dif ferent type o f s tructu ral s ys tem, roof s truct ure can include the f ollowing:

a. Purlins
b. Rafters (roo f jois ts )
c. Trus s es
d. Beams
e. Girders

Pitched roof des ign:

1) Determinatio n of s lope is bas ed on the foll owing facto rs :

a. Type of r oofing
b. Pres ence of attic, or cathed ral ceiling
c. Cos t
d. Expected s now load

2) The bas ic des ign princip le in the pitched roof is that by overlapping materials in the downs lope di rection, and by p rovidin g a waterproo f s urface, water wi ll not s it, but will be fo rced to ru b off the roo fing s urface.
Flat roof des ign:

1) A roo f is des ignated as flat id its s lope is les s than ten degrees .
2) Flat r oofs have tradit ionally been us ed in hot cli mates where water accumulation is not a p roblem.
3) They were gene rally unkown i n northe rn climated bef ore the end of the las t century.

Advantages of flat roo f des ign:

1) No s pace los t below roof, i.e. n o dead s pace
2) Les s material is us ed than in a s loped roo f
3) The r ooftop is poten tially us eful as a terrace, o r s leeping porch
4) Potentiall y pleas ing appearance
5) Eas ier to bu ild than a s loped roo f

Weatherproofing the flat roof:

1) The f lat roo f relied on s ome ki nd of mem brane fo r keeping mois tu re out. In dry climates this is done with clay tiles , but in Canada as phalt, or r ubber is neces s ary.
2) Flat r oofs are never actually flat, a s ubtle s lope directs s tanding mois tu re to drains at edges , or ins ide.

Flas hing
Flas hing is s pecial material us ed to make s ure that no mo is ture leaks in thos e areas of a roof that are particu larly vulne rable to penetrat ion. Areas where flas hing is comm only us ed:

1) Wherever the r oof is pierced by a chi mney, s kylight, ai r or pl umbing vent
2) Where roo fs meet walls
3) At the edges of flat roofs where t hey meet parapet walls (a wall t hat extends above the level of the roof )

M aterials from which flas hing is made of:
1) galvanized metal
2) aluminum
3) copper
4) building paper

Flas hing Des ign:
1) Sloped roofs : it is im portant t o des ign flas hing s o that it throws the water downs lope, and d oes not rely on mas tic.
2) Flat r oofs : it is imp ortant that flas hing be extended above the level at wh ich you expect s now or water to accumulate.

Ins ulation:
Becaus e hot air ris es , roofs los e more heat than walls , and thus require g reater degree o f ins ulation. There is a multi tude of di fferen t locations for the ins ulation in a roof, s ome o f which are lis ted here.

Sloped roo fs ins ulation location:
1) Res ting above ceiling.
2) Attached between rafte rs
3) Between the s ubs trate and the roofin g (a part icularly us eful method of the rafte rs are to be expos ed, but may res ult in overheating in the s ummer)

Flat roofs ins ulatio n location:
1) Between s ubs trate and roofing
2) Res ting above roofin g material (with ballas t p rovided to keep it fro m moving )

· Attic areas , or jus t dead areas in the roo fs cons tructed of t rus s es , are generally provided wi th ventilatio n s ys tems to allow in outs ide air.
· Vents are generally located under the eaves , at the gable ends , at the ridge, or by fans .
· Two main reas ons for keeping the att ic at outs ide temperatu re are as follows :

a) Summer heat
b) Winter hu midity
Pitched roof solutions

Isover mineral insulation material helps to keep rooms under the roof pleasently cool in summer and comfortably
warm in winter.

Low heating costs and improved noise protection are ensured for the lifetime of the house.

                                                                  New living spaces

                                                                  With attic insulation it is most easy to
                                                                  create new living space in new buildings
                                                                  and in renovation.
                                                                  Isover insulation ensures a quiet and
                                                                  comfortable indoor climate in all

                 "Enjoy quiet buildings"
                                                                  Isover - commfort and efficiency

                                                 Pitched Roof
Insulation between rafters with ventilation

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
1,5Plaster board fireprotection board
3,5 Air gap - mounting lathing 3,5/5

Vapour barrier

10,0 Isover lightweight glass wool between counter battens 5/10

20,0 Isover lightweight glass wool between rafters
4,0 Ventilation area
2,4 Under roof - rough formwork
0,3 Layer roof skin (e.g. polymer bitumen roll roofing)

5,0 Counter battens min. 5/5 - ventilation area
3,0 Roof lathing 3/5
Roof covering

The dimensions for the inlets and outlets of the ventilation area
depend on the roof pitch and the length of the rafters.
Full rafter insulation with diffusion-permeable underlay foil
and timber structure

Rw = 55 dB
U = 0,15 W/m²K

cm Composition

Wood covering

3,0 Air gap - mounting lathing 3/5
1,5 Plaster board fireprotection board
3,0 Air gap - mounting lathing 3/5
Vapour barrier

10,0 Isover lightweight glass wool between counter battens 5/10
20,0 Isover lightweight glass wool between rafters
2,4 Under roof - rough formwork
Layer of vapour diffusion-permeable spunbonded web

5,0 Counter battens min. 5/5 - ventilation area
3,0 Roof lathing 3/5
Roof covering

The dimensions for the inlets and outlets of the ventilation area
depend on the roof pitch and the length of the rafters.
Full rafter insulation with diffusion-permeable underlay foil
and metal track system

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
1,5 Plaster board fireprotection board

Vapour barrier

10,0 Isover lightweight glass wool
20,0 Isover lightweight glass wool between rafters
2,4 Under roof - rough formwork
Layer of vapour diffusion-permeable spunbonded web
5,0 Counter battens min. 5/5 - ventilation area
3,0 Roof lathing 3/5
Roof covering
Full rafter insulation with diffusion-permeable cladding

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
1,5 Plaster board fireprotection board
3,0 Air gap - mounting lathing 3/5
Vapour barrier
10,0 Isover lightweight glass wool between counter battens 5/10

20,0 Isover lightweight glass wool between rafters
2,4 Under roof - rough formwork
0,3 Layer roof skin (e.g. polymer bitumen roll roofing)

5,0 Counter battens min. 5/5
3,0 Roof lathing 3/5
Roof covering

Rafter insulation - timber structure

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
Wooden rafters are visible

4,0 Wood covering

Vapour barrier
20,0 Isover lightweight glass wool between rafters
10,0 Isover lightweight glass wool between rafters
2,4 Under roof - rough formwork
Layer of vapour diffusion-permeable spunbonded web

5,0 Counter battens min. 5/5
3,0 Roof lathing 3/5
Roof covering
Rafter insulation - timber structure

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
Wooden rafters are visible
4,0 Wood covering

Vapour barrier

20,0 Isover lightweight glass wool between rafters
10,0 Isover lightweight glass wool between rafters
2,4 Under roof - rough formwork
Layer of vapour diffusion-permeable spunbonded web

5,0 Counter battens min. 5/5
3,0 Roof lathing 3/5
Roof covering
Rafter insulation - timber structure with insulation between

Rw = 55 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
6,0 Lightweight glass wool between rafters
2,4 Under roof - rough formwork
Vapour barrier

12,0 Isover lightweight glass wool between counter battens 8/12

12,0 Isover lightweight glass wool between counter battens 8/12
Layer of vapour diffusion-permeable spunbonded web

5,0 Counter battens min. 5/5 - ventilation area
3,0 Roof lathing 3/5
Roof covering

The combined insulation offeres the advantage that the vapour
barrier is laid over the full area of the rough formwork, thus
avoiding damage by installation works. Care should be taken to
ensure that the vapour barrier is laid on the warm side in the first
quarter of the insulation layer.
Mono-pitch roof structure

Rw = 55 dB
U = 0,12 W/m²K

cm Composition
1,5 Plaster board fireprotection board
5,0 Isover lightweight glass wool between counter battens 5/5
Vapour barrier

1,5 Chipboard panel
10,0 Isover lightweight glass wool between timber
i-section beams

20,0 Isover lightweight glass wool between timber
i-section beams

1,5 Chipboard panel
Layer of vapour diffusion-permeable spunbonded web
8,0 Counter battens min. 8/8
1,5 Chipboard panel
0,3 Layer roof skin (e.g. polymer bitumen roll roofing)
Tin roof covering

Timber i-section beams are also ideal for use as roof rafters.
Advantages include the low dead weight, the low timber content
due to the reduced cross-sectional area, and use as prefabricated
roof pane and flooring elements.
Collar beam insulation

Rw = 50 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
3,0 Air gap - mounting lathing 3/5

Vapour barrier

16,0 Isover lightweight glass wool between collar beams

14,0 Isover lightweight glass wool between rafters
2,4 Wood covering
1,5 Plaster board fireprotection board
Transverse insulation

Rw = 50 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
3,0 Air gap - mounting lathing 3/5
Difunorm Vario

16,0 Isover lightweight glass wool between wood construction

14,0 Isover lightweight glass wool between rafters
2,4 Wood covering
1,5 Plaster board fireprotection board
Jamp wall

Rw = 47 dB
U = 0,15 W/m²K

cm Composition
1,5 Plaster board fireprotection board
3,0 Air gap - mounting lathing 3/5
Difunorm Vario
10,0 Isover lightweight glass wool between counter battens 5/10

20,0 Isover lightweight glass wool between wood construction
3,0 Air gap - mounting lathing 3/5
1,5 Plaster board fireprotection board

In order to avoid thermal bridges, thermal insulation must also be
fitted behind thejamp wall on the ceiling of the top floor. The
vapour barrier must not be omitted in this area.
Flat ("coffin-type") roof structure

Rw = 58 dB
U = 0,15 W/m²K

cm Composition
0,5 Plaster
16,0 Reinforced concrete structure
Vapour barrier

14,0 Isover lightweight glass wool between counter battens 8/14

18,0 Isover lightweight glass wool between rafters
Layer of vapour diffusion-permeable spunbonded web
5,0 Counter battens min. 8/5
2,4 Under roof - rough formwork
0,3 Layer roof skin (e.g. polymer bitumen roll roofing)
Tin roof covering
Sanidach (renovation)

Rw = 51 dB
U = 0,18 W/m²K

cm Composition
2,5 Interior plaster
3,5 Existing layer of insulation material
2,5 Air gap - mounting lathing 2,5/5
2,0 Isover rigid insulation board
Difunorm Vario
12,0 Isover lightweight glass wool between rafters
10,0 Isover lightweight glass wool between counter battens

2,2 Chipboard panel
Layer of vapour diffusion-permeable spunbonded web

5,0 Counter battens min. 5/5 - ventilation
3,0 Roof lathing 3/5
Roof covering

The thermal insulation is laid from the outside, so that the first
insultion layer protects the vapour barrier from projecting nails.
The Difunorm Vario humidity adaptive vapour barrier is laid over
the complete area between and over the rafters. The system
improves the thermal insulation properties of existing roofs.

Home > How To Library > Roofing > Asphalt Shingles > Asphalt Shingles

Asphalt Shingles
Asphalt shingles are an economical roofing solution. But
shop around, because not all shingles are the same.

 Related Showrooms
 • Western Red Cedar Lumber Association - Real Cedar for Siding, Decking and Outdoor

                                         Asphalt shingles are economical and
                                         versatile, which may be why they
                                         represent more than 80 percent of the
                                         roofing market. They're relatively
                                         inexpensive to buy and install, are
                                         suited to roof pitches from 4-in-12 to
                                         vertical, and are available across a
                                         wide range of quality, cost, and style.
                                         Easy to cut, fit, and fasten, asphalt
                                         shingles are compatible with many
                                         different kinds of flashing and edging
                                         products, and don't require specialized
                                         accessories for roof edges, wall
Available in a wide range of colors,     terminations, chimney or vent
traditional three-tab shingles require   flashings.
care during installation to achieve a
uniform appearance.
                                         Choosing Shingles
Credit: CertainTeed Corporation
                                   There are two kinds of asphalt shingles
                                   on the market: Fiberglass shingles and
organic-mat shingles. Both are made with asphalt, but fiberglass
shingles use a fiberglass reinforcing mat, while the organic kind use a
cellulose-fiber mat derived from wood. The organic mat of traditional
shingles has to be saturated with soft asphalt, then coated with a
harder asphalt for protection; the fiberglass shingles need only the hard
asphalt coating. Fiberglass shingles are thinner, lighter, easier to lug
around, and carry a better fire rating than organic shingles, but
organic-mat shingles are tougher and stay more flexible in cold
weather. Fiberglass shingles predominate in southern and central
regions, but organic shingles are still popular in the North and are
almost the universal choice in Canada.

Buyer Beware
When it comes to shingles, the drawbacks center on service life. While
asphalt shingles come with warranties ranging from 20 to as long as 45
years, roofers and builders remain skeptical of those warranties. Since
warranties are a marketing device, they are not a reliable predictor of
lifespan. In the past decade, there have been many complaints of
asphalt shingle failure long before warranties expired. Many
homeowners have been dissatisfied with warranty payouts that didn't
                                  cover all the costs of repair or
                                  replacement, as well.
                                    So rather than compare warranties, it's
                                    wise to demand shingles that meet
                                    industry manufacturing standards.
                                    Fiberglass asphalt shingles are covered
                                    by a standard called ASTM D-3462,
                                    which requires products to pass tear-
                                    strength and nail-withdrawal tests.
                                    Until recently, few shingles on the
                                    market actually passed the tests. But
                                    codes have been upgraded to permit
                                    only fiberglass shingles labeled as
                                    complying with this standard to be
                                    installed. Today some manufacturers
                                    even have the independent
Architectural shingles mimic the    Underwriters Laboratory certify that
appearance of products ranging from
natural stone to cedar.             they measure up. To check for
                                    compliance, look for the familiar UL
Credit: IKO Roofing
                                    logo on the label next to the ASTM D-
                                    3462 certification.
Organic-mat shingles are covered by their own standard, ASTM D-225. In
practice, organic shingles have a much higher tear strength and nail-
pull resistance than fiberglass shingles. They are also heavier because
of the additional asphalt used to make them. Old-time roofers used to
pick heavier shingles when they wanted a better brand; while this may
not hold true for modern fiberglass shingles, it's still a good rule for the
organic kind.

Shingles that pass the standards cost more than low-grade shingles.
However, installation is a big factor in total roof cost and, since it costs
just as much to nail on poor shingles as first-rate ones, cheap shingles
are rarely worth it.

Shingle Appearance
Asphalt shingles now come in all kinds of colors and profiles. The old 3-
tab shingles are still around, but a wide range of "architectural"
shingles, whose profiles suggest the random shadows and patterns of
slate, wood shingles, or ceramic tile, are readily available. These
specialty shingles often carry a longer warranty but, once again,
beware: Check to see that the shingle actually has two full layers, not a
half-width of lower lamination. Also, make sure the package is labeled
as complying with ASTM D-3462 or ASTM D-225.

Architectural shingles have a random pattern and, as a result, can be
                                  easier to lay out than the standard 3-tab kind. With a traditional
                                  shingle, you have to line up the tabs properly, or the roof will have a
                                  haphazard, wavy appearance. The surface pattern of the architectural
                                  shingles, on the other hand, obscures the shape of the shingles
                                  themselves, and provides the desired appearance while saving effort on
                                  the layout. This savings in installation time may actually help offset the
                                  sticker price associated with specialty shingles.

                                          Roof Slope
Roof slope is a very important aspect and it is considered the primary factor in roof design. The
slope of a roof has an effect on the interior volume of a building, the drainage, the style, and the
material you use for your covering. For example, if you noticed water collecting on your roof the
problem is probably related to the slope. The style is affected too because the framing of the roof
changes the slope.

The slope of a roof is often referred to as the pitch. The slope, or pitch, of the roof is determined
by the vertical rise in inches for every horizontal twelve inch (12") length (called the "run"). A
roof with x rise/12 run slope means that for every 12 inches horizontally (run), it rises x inches.
Below are some of the common roof slopes and the terms which classify them.

        Flat Roof: 2/12
        Low Slope: 2/12-4/12
        Conventional Slope Roof: 4/12-9/12
        Steep Slope: 9/12 and higher

Steeper sloped roofs are generally more visually pleasing and tend to last longer as well.
However, they also cost more because a steep sloped roof requires a taller chimney and more
lumber for framing. On average, a 12/12 roof can cost up to 50% more than a roof with a 4/12
slope. Many find that it is worth it though because the roofing material is estimated to last up to
50% longer and will require less maintenance in the long run.

Lastly, roof slope helps determine the appropriate materials for the roof. A roof with a 4/12 pitch
will allow products such as shingles or tiles. However, these materials do not work well on low-
slope roofs. Likewise, a single-ply membrane or a built-up roof will not be appropriate for a
high-slope roof.

[edit]   Types of Asphalt Shingles
Two types of asphalt shingles are used: organic and fiberglass or glass fiber.
Organic shingles are generally paper (felt) saturated with asphalt to make it
waterproof, then a top coating of adhesive asphalt is applied and ceramic granules
are then embedded. In the case of algae-resistant shingles, a portion of the granules
contain leachable copper or tin designed to inhibit moss growth and discoloration
from algae on the roof.

Shingles are judged by weight per square. Organic shingles contain around 40%
more asphalt per square (100 sq. ft.) than fiberglass shingles which makes them
weigh more and gives them excellent durability and blow-off resistance. Shingle
durability is ranked by waranteed life, ranging from 20 years to 50 years; in some
cases lifetime warranties are available.

Fiberglass shingles have a base layer of glass fiber reinforcing mat. The glass fiber
mat is not waterproof by itself. Fiberglass mat is made from wet, random-laid
fiberglass bonded with urea-formaldehyde resin. The mat is then coated with asphalt
which contains mineral fillers and makes the fiberglass shingle waterproof.
Fiberglass reinforcement was devised as the replacement for asbestos paper
reinforcement of roofing shingles and typically ranges from 1.8 to 2.3 pounds/square

The older asbestos versions were very durable and hard to tear, an important
property when considering wind uplift of shingles in heavy storms. Fiberglass is
slowly replacing felt reinforcement in Canada and has replaced mostly all in the
United States. Widespread hurricane damage in Florida during the 1990s prompted
the industry to adhere to a 1700 gram tear value on finished asphalt shingles.

A newer design of fiberglass asphalt shingle, called laminated or architectural, uses
two distinct layers which are bonded together. Laminate shingles are heavier, more
expensive, and arguably more durable than traditional shingle designs. Laminated
shingles also give a more varied, contoured visual effect to a roof surface.

[edit]   Durability
Asphalt shingles usually last longer in cooler climates than warmer ones. Thermal
shock is one thing that is damaging to shingles (thermal shock is what roofing
materials experience when the ambient temperature changes dramatically within a
very short period of time). Another factor affecting asphalt shingle roofs is attic
ventilation. Proper roof ventilation has been known to extend the service life of a
roof. Shingles should not be applied during cold weather. Each shingle must seal to
the layer below it to form a monolithic structure. Sun and heat to soften the
underlying exposed asphalt is a requirement during the initial phase of a new roof.
Staple guns should not be used on shingles because they tear into the substrate too
easily. Traditional roofing nails remain the best method of applying shingles.

Types of Roofing
The most common types of roofing materials for residential structures are: asphalt shingles,
wood shingles and shakes, metal roofs, tile, slate and composite coverings.

ASPHALT ROOFS: This is the most commonly used and least expensive roof covering
material. Asphalt roofing materials consist of either a rag fiber or a fiberglass mat impregnated
with asphalt and covered with colored mineral granules. A wide variety of designs, weights,
colors and sizes are available.

Asphalt roofs show their age when the mineral granules wear off, reveal the black asphalt and
the corners and edges of the shingles begin to curl and crack. This is an indication that the
asphalt composition has begun to dry out and lose its weather-proof seal. When only a few
shingles show the above type of wear, the simple and less costly replacement of worn out
shingles may be all that is needed. If one out of every five to ten shingles shows this wear and
aging, it is may be time to re-roof.

WOOD SHINGLES AND SHAKES: Shingles made of cedar, cypress or red wood are highly
rot-resistant and may last 30 to 35 years if properly installed and maintained. The best wood
roofing materials are pressure-treated with wood preservatives. When considering home safety, it
is wise to note that wood shingles and shakes are more highly combustible than the other roofing
materials available. If a wood shingle is your choice, look for one treated with fire-retardant

As wood shingles and shakes age they may shrink and form gaps between each shingle. They
may also become brittle and offer less protection from the elements. As is the case with asphalt
shingles, if only a few wooden shingles show this wear and tear, replace the individual shingles.

METAL ROOFS: Metal roofs are highly resistant to damage from the elements and may
frequently last 40 years or more. They are highly fire resistant and require little maintenance.
Small damaged areas can be repaired with patches of similar metal. The materials used in a metal
roof may include copper, tin, steel, aluminum, lead or an alloy combination of one or more of
these metals.

TILE, SLATE AND COMPOSITES: Roofs made of slate or tiles composed of either clay or
concrete are perhaps the longest lasting available. They frequently survive more than 50 years,
and normally require little or no maintenance. In addition these materials are extremely fire
resistant. When one of these roofs does need replacement, however, the cost can be very high.

Tiles offer comparable benefits to slate but come in a more decorative and cosmetically-pleasing
variety of colors, textures, shapes and sizes. Tiles can be glazed or unglazed. Slate typically
comes in only black, grey or dark red.

Types of Roof Coatings

Roof coating has become an effective and popular method of extending the life of a roof. It can
add protection against weather and fire, may increase energy efficiency and can even be used to
change a roof’s color. But is is no substitute for repairs to a defective or worn out roof.
Consequently, roof coatings should be applied before any serious roof deterioration occurs.

Maintenance roof coatings or cold process roof coatings are ready-to-use protective coatings for
roofs and other areas exposed to the elements. They come in a liquid or semi-liquid state and are
applied by brush, roller or spray. Roof coating professionals generally use coating materials that
can be grouped into the following five categories:

ASPHALT-BASE COATINGS: Asphalt-Base Coatings come in three different types:
emulsion, solvent or aluminum pigmented.

• Emulsion Type Coating is adaptable over asphalt built-up roofs, metal roofs and those
similarly composed, provided there is adequate drainage. When applied in the proper thickness,
it chalks slowly and doesn’t blister. It can be applied over a damp surface and will not flow
under heat. It does require temperature and humidity conditions that permit thorough water
evaporation before the coating can be subjected to rainfall, freezing, or standing water. Emulsion
coating requires a clean and a primed surface for good adhesion.

• Solvent Type Coating can be applied over asphalt, composition, asbestos-cement, metal and
masonry roof surfaces. It can be applied on a clean, dry surface over a wide temperature range
and is relatively free of wash-off problems after a short drying period. It has good water
resistance and may not require a primed surface for good adhesion. Solvent coating may flow
under extreme heat and is combustible. It is susceptible to blistering if applied over a damp
surface or any material containing moisture.

• Aluminum Pigmented Coating consists of flake aluminum particles dispersed in solvent type
asphalt coatings. It can be applied over asphalt, composition or metal roofs having adequate
drainage and provides a reflective or decorative surface. The coating’s reflectivity helps improve
a buildings energy efficiency by deflecting ultraviolet rays and reducing the roof’s temperature.
The cost of this coating is higher than most and its applications over low melt asphalt roofs can
result in discoloration and scaling. It is susceptible to blistering if applied over a damp surface or
any material containing moisture.

ALKY-BASE COATINGS: Alkyd-base coatings can be applied over metal, composition or
masonry roofs that have adequate drainage. They perform the same functions as aluminum
pigmented coating. Although alkyd-base coatings cost more, they are often selected because of
their decorative versatility. They will not flow under heat and are susceptible to blistering if
applied over any damp material. Alkyd-base coatings tend to discolor and/or split when applied
over low melting point asphalt and are combustible.

• Acrylic Latex Coating: Acrylic latex coating comes in liquid form and is available in various
colors; white being the most common. White and other light colors reflect the sunlight, keeping
the interior of a building cooler and conserving energy during warmer months.

• Refined Coal Tar Coating: Refined coal tar coating is used for re-coating tar and gravel roofs.
In preparation, the gravel must be removed and roof surface broom cleaned. Proper protection
requires approximately seven gallons per 100 square feet, and gravel should be re-applied over
the coating. It is self-heating at warm temperatures, is very water resistant and can be used where
the roof is subject to standing water. Refined coal tar tends to be brittle in cold weather, and its
use is restricted to relatively flat roofs.

• Flexible Ceramic Coating: Flexible Ceramic Coating is a relatively new addition to the roof
coating business. The primary attraction of a ceramic coating is its insulation properties that
allow for energy efficiency. As a result of its flexible nature, ceramic coatings help seal cracks
and hide surface flaws. It has proven particularly popular in warmer climates.

The Roof Inspection

Some roofing contractors provide inspection service free-of-charge in an effort to solicit work.
You should expect a roofing inspector to pay close attention to roof penetrations, flashings and
distress areas such as blisters, curling and cracks. Tell the inspector about any problems you
yourself may have noticed; particularly during the rainy or snowy seasons.

The inspector's findings will likely put your home's roof into one of the following categories:

• Materially sound—not currently in need of repair or maintenance work.

• In need of patchwork and coating.

• Requires resurfacing with a new membrane.

• Deteriorated to the extent that it requires total removal and replacement.

Hiring a Roof Contractor

If you determine that you will need some roof work done, take the time to evaluate the roofing
contractor who may be doing the job.

The following guidelines will help in you choose a qualified, experienced roofer:

• Check for a permanent place of business, telephone number, tax I.D. number, and (where
required) a business license.

• Insist on seeing copies of the contractor's liability insurance coverage and workers'
compensation certificates. Make sure the coverages are in effect through the duration of the job.
• Look for a company with a proven track record that readily offers client references and a list of
completed projects. Call these clients to find out whether they were satisfied.

• Check to see whether the contractor is properly licensed or bonded. Call your state's licensing
board for your state's specific requirements (where applicable).

• Insist on a written proposal and examine it for complete descriptions of the work and
specifications, including approximate starting and completion dates and payment procedures.

• Check to see if the contractor is a member of any regional or national industry associations (See
back panel for a listing of such associations).

• Contact your local Better Business Bureau to check for a business report or any complaints that
have been filed on a contractor at

• Have the contractor explain his or her project supervision and quality control procedures.
Request the name of the person who will be in charge, how many workers will be required and
the estimated completion time.

• Carefully read and understand any roofing warranty offered and watch for provisions that
would void it. The lowest bid is not always the best option. Remember, price is only one
criterion for selecting a roofing contractor. Professionalism and quality workmanship also should
weigh heavily in your decision.

      National Roofing Contractors Association
      Cedar Shake & Shingle Bureau
      National Tile Roof Manufactures Association
      The Roofing Mall
      TrussNet
      CyberRoofer Good Practical Advice

Roof Drainage - Gravity roof drainage and siphonic roof
AQUAPASS® channels are suitable
for application classes M 125/B 125
according to EN 1253/EN 124. Also
suitable for classes C 250 and E 600
when used with a special
supporting frame and grating.

Typical applications




Car park deck drainage

Green roof drainage
JET flat roof gully in cast iron for
siphonic drainage from DN 50 to
DN 80

 Typical applications

 Large roofs such as:

   Shopping centres

   Industrial warehouses

   Football stadiums

   Office and administration

Roof Coverings and Materials
When it comes time to put a covering on your roof, you will have many choices before you.

You will want to be sure to choose a material that will last for a long time, maintain it's color
through out the years and is price efficient.

Asphalt shingles: This is generally the most common type of roofing material used in the United
States. It is an excellent material to be used on pitched roofs. These are usually reinforced by
organic or fiberglass material. Organic reinforcement provides a shorter life and is less fire
resistant than their fiberglass counterparts. Fiberglass roofing shingles are the most popular.
 Asphalt roofing shingles come in different grades and usually have an expected life of 20-50
years depending on the price. Depending on where you live the life span can be different because
of the varying climates.

Laminated fiberglass shingles: These are similar to asphalt shingles and do contain many of the
same materials, but they are thicker and more durable and give a much nicer texture to your roof.
They can cost twice as much but do last longer...up to thirty years.

Wood shingles: You will find that these are also called wood shakes. Wood shingles are made
from treated wood or naturally water resistant woods such as cedar or red wood. One thing to
keep in mind about wood shingles is that they are not very fire resistant and can cost up to five
times more than an asphalt shingle. They are very appealing to the eye and give a warm elegant
look to a roof.

Slate roofing: It will come in various grades and colors. It gives the roof a very elegant look
with its textures and styles. One of the nice things about slate roofs is that it is a very high quality
roof and has low maintenance. It's life could be 100 years or more. One downfall is the cost. Not
only is the material expensive, it needs to be installed by a qualified roofer whose labor charges
can be quite high also.

Tile roofing: This roof is available in concrete or clay and comes in many colors. Because of
this, it is becoming a very popular roof covering. It will come in a curved or rounded shape that
will bring visions of Spanish style houses and it also comes as a flat tile. Beware that this is a
heavy material and as such your frame work of the roof needs to be built to withstand the weight
loads. It's cost is similar to that of wood shingles but it will last up to and over 50 years and has
no fire hazard.
Metal Roofs: This roof is light weight and durable. The more it is used, the more popular it is
becoming. It will come in large sheets or in shingle formats. These are a very safe roof in all
types of weather. They generally have a life of 30 years, but some manufacturers will give a life
time warranty. They are generally a higher cost of most roofing materials but are low
maintenance and have a high fire rating.

Roofs and Roof Tiling
Roofs are categorized as being either pitched or flat. A pitched roof can be constructed in three
Trussed roof: Pre-made sections called trusses are placed on top of the load bearing walls or
Traditional Roof: Sections of the chosen material, usually timber in domestic construction, are
                                                               built together in-situ. Or by
                                                               combining both methods.

                                                                The word truss means tied together
                                                                and roof trusses are sections (again,
                                                                usually of timber) fixed solidly
                                                                together to form the angled shape
                                                                required for the pitch of the roof.
                                                                Most pitched roofs have an equal
                                                                pitch (symmetrical pitch) on both
                                                                sides of the ridge but there are
                                                                many variations on this theme. A
                                                                mono-pitch may just have one
                                                                sloping side coming down from a
wall, an inverted pitch or Butterfly roof has two sides sloping inwards to a valley at the bottom
of the pitches, an asymmetrical pitch with one side of the roof slope at a different angle to the
other. An asymmetrical butterfly, or a lean to roof. A lean-to roof is the most commonly
constructed by our many thousands of customers on the web site and even though it is a much
smaller project than a huge, main roof, the principles are exactly the same. The timbers must be
the right size to support the structure. The tiles must be put on in the correct way and the top of
the roof must be sealed against water penetration.

Whatever the roof, it is generally designed to give you, and the inside of the property, the best
protection possible from the weather. Roof design is quite a complex field and involves many
calculations regarding the strength of the materials used. A roof has to withstand very high wind
speeds and snow loading and each roof is designed to carry the covering, eg tiles, that is put on
it. A conservatory roof designed for clear plastic (Poly carbonate) roofing sheets would not be
able to carry the weight of concrete or clay roof tiles. It is important for the DIY'er to realise that
a roof is constructed the way it is for many reasons and it is not safe in any way to alter that
composition with consulting an architect.

We have had so many instances of people wanting to convert their loft into a bedroom or living
room, or even just put in a loft window. Timbers have just been removed, the roof weakened and
the roof has started to sag. Even experienced roofing carpenters work on the principle that for
every roof timber that is removed, at least two have to be put back. The skill of the tradesman is
knowing where to put them.

We will go through each roof part on a pitched roof in later paragraphs but as an overview it is
useful to know that roofing in the UK is generally covered with small sections like tiles and
slates because they are easier to get up onto the roof, safer to handle when you are up there and
finally, are small enough to allow for contraction and expansion in the dramatic temperature
changes we get in this Country. These parts are laid, much the same as bricks, in an overlapping
way but not for strength as with the bricks, but so two joints do not fall on top of each other to
allow water penetration. The covering is usually fixed onto battens which are spaced out up the
roof . Each batten is nailed to every rafter it passes over.

Underneath the battens is a roofing felt. There are various makes of felt but each one serves as
both a vapour and a dust barrier. That is, it stops warm air from inside the roof space hitting the
cold underside of the tiles where it may have condensed. Water, condensing on tiles, is the single
most reason for rot in roof timbers. It also stops dust and road fumes etc entering the roof space.

Many people (unfortunately some Cowboy Builders included) think (and tell customers) that
roofing felt is a secondary waterproof layer for the roof. It is not and in fact ventilation holes are
deliberately left in the felt in some roof constructions.

Bearing in mind the felt under the tiles, and the pitch of most roofs, it is almost impossible to tell
where, when a roof is leaking, where it is leaking from.
The water can get through a broken tile or slate and run down the felt until it collects in a sagging
bit of felt, or just drips through an unnoticed puncture in the membrane. Water can be getting in
because of a broken ridge tile but not be evident until it is seen running down the far wall in the
bedroom. This makes leak diagnosis on a roof an expensive pastime and results in many people
trying to find the leak themselves.

Never attempt to work on a roof without a scaffold. Tiles are constantly under the hammer from
our weather and as such can be very slippery even on the driest of days. We have witnessed
many falls from height in 35 years of building and we have not found a single human being yet
that bounces. If a professional wants to wander about on your roof without a scaffold, and he is
insured against the damage he can cause to your roof on his way down, its his problem, but do
not try it yourself.

                                                     Roof Trusses:
                                                     Most ordinary house roofs in this country are
                                                     formed by roof trusses. These trusses are
                                                     designed for each particular type of dwelling and
                                                     as many of our houses are built to the same style,
                                                     so there is one very popular truss type. This is the
                                                     Fink Truss. The fink truss is a duo pitch truss, that
is it has two sloping sides meeting in the middle. Roof trusses are placed on top of the load-bearing
external walls of a building. They are placed at regular, equal intervals to suit the type of load they are to
carry. The heavier the load, the narrower the spacing or the larger the timbers used to make the truss. A
normal spacing for a roof truss in a domestic situation is 600mm.

Roof trusses remain upright because they are tied together by binding timbers which are fixed to the
underside of each truss. The end truss or couple of trusses is fixed to the inside skin of the gable end
(see roof diagram above) wall to make sure that the trusses do not achieve the “domino” effect. When a
roof is battened for tiling this also helps the tying together.

The bottom, horizontal timber of a roof truss is also a ceiling joist. As far as its load bearing capacity is
concerned it is only designed to hold up the ceiling of the room below and perhaps a few empty
suitcases in the attic. It is not designed to be walked, slept or danced on and neither is it designed to
carry the entire contents of the last five offices you worked at. Our later section on loft conversions
covers what you may and may not do in the loft.
Water tanks placed in the loft are placed on strengthened platforms which spread the weight over a
number of trusses.

A roof space is not designed to be hot (unless of course it has been converted). The heat is meant
to stay in the building and now, with the latest amendments to Part L of the Building Regulations
(The conservation of fuel and power) it is expected that (when all condensation and boarding out
problems are considered) your existing loft insulation is topped up to at least 200mm. This is to
be placed between, and over the ceiling joists. As mentioned in our sequence of events section, it
is important not to cover cables and light fittings with this insulation. The insulation will stop
heat from the building rising through it.

                                                                            Insulating a roof in this way
                                                                            means that the loft space itself
                                                                            is always quite cold. It is
                                                                            therefore necessary to insulate
                                                                            water tanks and pipes as in this
                                                                            “cold roof” design it can often
                                                                            be as cold in the roof space as
                                                                            it is outside. This is why many
                                                                            burst pipe situations (See
                                                                            repairing a burst pipe project
                                                                            P13) originate in the loft.

                                                                            When a roof is designed, as
                                                                            most roofs are, as a cold roof,
                                                                            it is important that the roof is
                                                                            adequately ventilated. If air
remains still for any period of time it warms up and in that warming it collects water vapour. The
warmer the roof space the more humid (containing water vapour) the air. When that warm air
hits any colder surface such as the underside of the tiles or even the water tanks in the loft, It
condenses. This means the vapour turns to water. The water soaks into timbers in the roof and
can cause much damage.

The insulation in the loft should therefore be stopped short of the edge, or eaves, of the loft floor
as can be seen in the diagram. Roof construction, in cold roof scenarios, allows cold air to pass
through the eaves into the loft. This should keep the loft at a constant temperature thus avoiding
condensation. The air is admitted through air vents known as soffit vents which are placed in the
soffit board between the facia board and the external wall of the house.

Pitched roof covering:
As already stated, pitched roofs are usually covered with tiles or slates which fix, or clip over,
battens. These battens sit on a roofing membrane and are fixed to the rafters below. The battens
are fixed at regular intervals according to the gauge (distance between battens) specified by the
tile manufacturer. This in turn will vary according to the angle, or pitch, of the roof.

Each tile must overlap the tile below it and this is the critical factor in working out how to tile
even the porch roof we mentioned above. The table below shows the lap and spacing for a
variety of common tiles. If you are unsure which tiles you have, simply zoom in on them with a
digital camera and the local Builders Merchants will be able to identify them for you. Before
reading the table below there are things you need to know.
The first column in the table, Tile Name, may sound strange but every tile has a name to
distinguish it from the others. The two main players in the roof tile market are Marley and
Redland. Marley started making roof tiles in 1924 and Redland in 1919, both are still going
strong with a huge range of tiles and slates. Different types of tile vary hugely in size with the
small clay, or concrete “Plain tiles” at only 265 x 165mm compared to the largest of roofing
slates at a giant 600 x 300mm. Both Marley and Redland manufacture similar tiles but they do
not quite interlock with each other. It becomes very important then to identify your tiles

The next column is the size of the particular tile. Tiles are always longer than they are wide.
Next is the minimum pitch. The angle a roof sits at is called the pitch and this pitch angle is
measured from the horizontal. A flat roof therefore would be 0 degrees. As you can see from the
diagrams one tile overlaps the one below it and if the pitch is too shallow for a given the, the
wind and rain can drive up under the tile. Each make of tile has a minimum pitch onto which it
can be used safely. Sometimes by increasing the overlap of the tiles (Headlap) the pitch can be

The maximum pitch speaks for itself but is included because roof tiles are not meant to “hang”
on their battens. The volume of weight must press down onto the roof surface so ordinary roof
tiles should not be put on a roof that is too steep.
The minimum headlap is the smallest amount one tile can overlap the one below it. Sometimes
this figure has a tolerance and, together with the gauge (distance between the tops of the battens)
the roof tiles can be adjusted so the top course of tiles finishes right up at the peak, or Ridge, of
the roof.


       Concrete Interlocking Tiles

                                             Min.       Max.
               Tile Name           Size                          Min. Headlap Max. Gauge
                                             Pitch      Pitch
                                  418 x
       Renown                                 30°        44°           75             343
                                  418 x
       Redland 50                             30°        44°           75             343
                                                                                     At 22.5°
                                                                  75 headlap
                                                                                    pitch and
                                                                   at + 22.5
                                  418 x                                            over 343 at
       Regent                                17.5°       44°       pitch 100
                                   332                                             22.5° pitch
                                                                 headlap at -
                                                                                    and under
                                                                   22.5 pitch
                                  418 x
       Grovesbury                            22.5°       44°           75             343
                                                                                     At 22.5°
                                                                 75 headlap at      pitch and
                                  381 x                           + 22.5 pitch     over 343 at
       Norfolk Pantile                       22.5°       44°
                                   227                            100 headlap      22.5° pitch
                                                                 at - 22.5 pitch    and under
                                                                                     At 22.5°
                                                                 75 headlap at      pitch and
                                  381 x                           + 22.5 pitch     over 343 at
       Redland 49                            22.5°       44°
                                   227                            100 headlap      22.5° pitch
                                                                 at - 22.5 pitch    and under
                                  430 x
       Delta                                 17.5°       44°           75             355
       Relland Bridgewater        418 x
                                              30°                      75             343
       Tile                        330

      Interlocking Slate Tiles
                                   Min.     Max.
      Tile Name           Size                        Min. Headlap Max. Gauge
                                   Pitch    Pitch
                         430 x
Stonewold                          17.5°     44°           75             355
Redland                  412 x                          Min.112         Min.253
                                   22.5°     44°
Richmond                  332                           Max.159         Max.300
Redland                  300 x                                          Min.210
                                    25°      69°      Max.90 Min.
Cambrian                  336                                           Max.250
                                                       at ridge 75
                        365 x
                                                      95 or 75 over
Caplestone             widths of    30°                                   270

Concrete Plain Tiles

                                   Min.     Max.
      Tile Name          Size                       Min. Headlap Max. Gauge
                                   Pitch    Pitch
Plain                  268 x 165    35°    Vertical      65         100
Ornamental             268 x 165    70°    Vertical      35         115
Download               268 x 165    35°    Vertical      65         100

Clay Plain Tiles

                                   Min.     Max.
      Tile Name          Size                         Min. Headlap Max. Gauge
                                   Pitch    Pitch
                         265 x
Rosemary                           40°     Vertical       65             100
                         265 x
Cheslyn                            40°     Vertical       65             100


Concrete Tiles

      Tile Name          Size      Min.     Max.          Min.        Max. Gauge
                                  Pitch    Pitch     Headlap
Double Pantile        420 x 334   17.5°                75          345
Calderdale Slate      420 x 334   17.5°                75          345
Shire Pantile         380 x 230   22.5°                75          305
Double Roman          420 x 334   17.5°                75          345
Bold Roll             420 x 334   22.5°                75          345
Lindum                420 x 334   22.5°                75         3455
Standard Pattern      380 x 230   22.5°                75          305
Plain Tile            265 x 165    35°                 65          100

Clay Tiles

                                  Min.     Max.
         Tile Name      Size                       Min. Headlap Max. Gauge
                                  Pitch    Pitch
                       347 x
County Panttile                   22.5 °               64          320
                       381 x
Europa                            22.5 °               62          320
                       370 x
Interlocking                      22.5 °               102         267
Plain Tile
                       265 x
Humber Plain Tile                 35 °                 65          100
                       265 x
Goxhill Plain Tile                40 °                 65          100
                       342 x
Arcadia Pantile                   30 °                 72          270
                       342 x
Old English Pantile               30 °                 72          270
                       342 x
Greenwood Pantile                 30 °                 75          267
                       420 x
Bridgewater                       30 °                 75          345
Double Roman
                       342 x
Gaelic                            30 °                 75          267

Slate Tiles
                                      Min.       Max.         Min.
      Tile Name           Size                                          Max. Gauge
                                      Pitch      Pitch       Headlap
Balmoral Clayslate      370 x 223    22.5°                    102           267
                                    17.5 °at
Britlock                360 x 340      120                      75          285
                                     20 ° at
                                                                          267 at 75
Britslate - duchess     610 x 305      130                      65
                                    22.5 ° at
                                                                          217 at 75
Briteslate - Countess   510 x 225      115                      65
                                    22.5 ° at
                                                                          202 at 75
Pennine - Standard      480 x 429       90                      75
                                    22.5 ° at
                                                                          202 at 75
Pennine - Small         480 x 280       90                      75


Plain Tiles

                                     Min.        Max.          Min.
      Tile Name           Size                                           Max. Gauge
                                     Pitch       Pitch       Headlap
                          267 x                              Roof 65      Roof 100
Plain Tiles                           35 °      Vertical
                           187                             Vertical 37.5 Vertical 115
                          267 x                              Roof 65      Roof 100
Heritage Plain Tile                   35 °      Vertical
                           187                             Vertical 37.5 Vertical 115
                          270 x                              Roof 70      Roof 100
Thaxden Plain Tile                    35 °      Vertical
                           168                              Vertical 40 Vertical 115
                          267 x                              Roof 65      Roof 100
Marlden Plain Tile                    35 °      Vertical
                           168                             Vertical 27.5 Vertical 115
                          333 x
Ashmore Double Tile                  22.5 °     Vertical        77          190

Interlocking Slate
                                  Min.                    Min.
      Tile Name         Size               Max. Pitch               Max. Gauge
                                  Pitch                 Headlap
                                22.5 at 75
                                                      75 headlap at
                        420 x                          22.5 pitch
Duo Edgemere                     17.5 at Vertical                      345
                         330                          100 headlap
                                                      at 17.5 pitch
                                22.5 at 75
                                                      75 headlap at
                        420 x                          22.5 pitch
Edgemere                         17.5 at Vertical                      345
                         330                          100 headlap
                                                      at 17.5 pitch
                        325 x
Marquess                         22.5 °    Vertical       75           250
                                                    50 headlap at   250 max at
                        327 x                       +20 pitch 65    50 headlap
Melbourn                          15 °     Vertical
                         300                         headlap at -   235 max at
                                                      20 pitch      65 headlap
                        325 x
Monarch                          22.5 °    Vertical       75           250
                        325 x
Duo Marques                      22.5 °    Vertical       75           250
                        325 x
Dalestone                        22.5 °    Vertical       75           50

Interlocking Tiles

                                 Min.                   Min.          Max.
      Tile Name         Size             Max. Pitch
                                Pitch                  Headlap        Gauge
Ashmore Double Plain 333 x 267 22.5 °     Vertical       77            190
                              30 ° at 75
                       387 X     22 °
Anglia Plus Tile                          Vertical        75           312
                        229    Smooth
                                at 100
                       420 X
Bold Roll Tile                  17.5 °    Vertical        75           345
                                 22 °
Ludlow Plus Tile     387 x 229 at 75      Vertical        75           312
                       granular /
                         22.5 °
                       smooth at
                          25 °
                       Smooth /
               420 X        30
Double Roman                        Vertical   75   345
                330     granular
                          at 75
               420 X   30 ° at 75
Ludlow Major                        Vertical   75   345
                330     Headlap
                        17.5 ° at
               420 X    Headlap
Malvern                             Vertical
                330      15 ° at
                         22.5 °
                       Smooth /
               420 X      at 75
Mendip                              Vertical   75   345
                330     headlap
                         at 100
                         22.5 °
                          at 75
               420 X    Headlap
Duo Modern                          Vertical   75   345
                330      17.5 °
                       smooth at
                         22.5 °
                       Smooth /
               420 X        30
Modern                              Vertical   75   345
                330     granular
                          at 75
               420 X
Wessex                    15        Vertical   75   345
        Forticrete (Anchor)

                                                      Min.                    Min.
                Tile Name                 Size                Max. Pitch                         Max. Gauge
                                                      Pitch                 Headlap
                                                      10 ° -
                Centurion             230 x 385                  44 o          100                    285
                                                      12.5 °
                Clay Plain            265 x 165        35 °      90 °           65                   100
                                                     22.5 ° -             80 - 95, 75 -           175 - 190,
                  Gemini              270 x 337               29 ° - 70 °
                                                       30 °                     95                175 - 195
                                                     22.5 ° -             80 - 95, 75 -           175 - 190,
                 Minislate            270 x 337               29 ° - 70 °
                                                       30 °                     95                175 - 195
                Rivenslate            270 x 330       22.5 °     70 °       80 - 95               175 - 190
Roofing the Right Way

Your roof is your home's first line of defense from the elements. But sun, wind and rain all wear down your roof
over time.

Since your roof is the largest component of your house it can also be the most vulnerable to severe storms and the
costliest single site of damage.

That's why it's important to make sure your roof is built the right way, with the right materials by a qualified
licensed contractor.

Whether you're planning to re-roof now or years from now, this brochure will help you navigate the process, choose
the right materials and show you how proper roof maintenance can identify problems before they become financial

Signs of a Problem

When it rains, do too many roof granules wash away? Are there water stains on your ceiling? Even the smallest leak
or curling shingle can be a sign of trouble. That's when it's time to hire someone who knows what to look for.

Hiring a Contractor

Quality installation is an important part of the roofing equation. When choosing a contractor, the National Roofing
Contractors Association ( says you should:

        Get bids from reputable contractors and check their references.
        Request verification of insurance.Make sure the bid clearly defines the work that will be done, including
         hauling away of debris and yard cleanup.
        Specify within the contract a time frame for completion.
        Do not pay the full amount up front (one-third is usually sufficient) and do not make final payment until
         you verify the job is complete.
        Make sure the contract is signed by both parties.

Choosing Materials

You want your home to look nice. But while people typically select the look and color of roofing materials, they
often leave key features, like resistance to the elements - hail impact, high wind and fire - to the contractor.

It's important to understand why some roofing products work better in certain parts of the country than others. In
addition to the weather your homes faces on a daily basis and disasters that could be a threat, the shape or type of
roof also dictates which materials will better protect your home.

Asphalt shingles (reinforced with fiberglass):

        Relatively low cost and easy to install
        Good fire resistance (usually Class A)
        Class 3 and 4 impact resistance is available, should be used in hail regions
        Available with wind warranties up to 130 mph, if installed in accordance with manufacturer's high wind


        Long life
        Lightweight
        Popular for low and steep-slope roofs
        Often receives cosmetic damage from hailstorms, but Class 4 product rated for impact resistance are
        Product available with Class A fire rating


        Quarried in the Northeast and Virginia
        Very strong
        High quality slate can outlast most other roofing material
        Requires special skill and experience for installation, which can affect cost
        Heavy so your contractor should verify the structure can hold the weight if you are replacing another kind
         of roofing material

          Good in dry climates
          Solid, long lasting product
          Higher threshold for hail damage
          Can be more permeable than other products if exposed to blowing rain
          Heavy so your contractor should verify the structure can hold the weight if you are replacing another kind
           of roofing material


          Good in dry climates
          Thinner products can be susceptible to hail damage, especially after aging
          Some building codes limit use because of wildfire concerns, but some product can be Class A fire rated
           with factory applied fire-resistant treatment
          Often used in wrong climates for cosmetic reasons

Roof System Components

Most roof systems have five basic components. Each plays an important role in the life of your roof.

1. Roof covering: shingles, tile, slate or metal and underlayment (tar paper beneath covering) to protect sheathing
from weather.

2. Sheathing: boards or sheet material fastened to roof rafters to cover a house.

3. Roof structure: rafters and trusses built to support the sheathing.

4. Flashing: sheet metal or other material installed into a roof system's joints and valleys to prevent water seepage.
5.Drainage: a roof system's design features, such as shape, slope and layout that affect its ability to shed water.

Care and Maintenance

For most consumers, their single largest investment is the home. Just like anything else, it needs to be maintained,
and that goes for your roof, too.

These simple maintenance tips can help your roof last longer:

        Proper eave and ridge ventilation may help extend roof life by reducing the buildup of heat and moisture.
        Keep trees trimmed to prevent them from rubbing against the roof, or from providing excessive shade.
        Keep roof, valleys, gutters and downspouts free from leaves, twigs and other litter that can build up and
         prevent proper drainage.
        Preservatives available for some roof types may help limit weathering effects of moisture and retard
         growth of molds and mosses.

Roofing products have changed significantly over the years. There are a wide range of choices in material,
appearance and price. When it's time for a new roof, make sure you're Roofing the Right Way, by choosing
materials that will help protect your home for many years to come.

The Institute for Business & Home Safety has additional recommendations to help build a stronger roof, as outlined
in its "Fortified...for safer living" new construction criteria. These include secure connections anchoring the roof to
the walls; a thicker (5/8") plywood deck fastened to the rafters with stronger nails in more places; roofing tape at
deck joints, and thicker (30#) felt to give two more lines of protection against water intrusion. Consult the IBHS
Fortified Home Builders' Guide for more information.

To see Underwriters Laboratories, Inc. list of certified clients and UL2218 impact resistant roof materials, click

From Wikipedia, the free encyclopedia
Jump to: navigation, search

For automobile roofs, see Sunroof.

The roofs of Olomouc, Czech Republic.

The roofs of Vietnam.
The roofs of San Cristobal de las Casas, Mexico.

A roof is the covering on the uppermost part of a building. A roof protects the building and its
contents from the effects of weather. Structures that require roofs range from a letter box to a
cathedral or stadium, dwellings being the most numerous.

In most countries a roof protects primarily against rain. Depending upon the nature of the
building, the roof may also protect against heat, against sunlight, against cold and against wind.
Other types of structure, for example, a garden conservatory, might use roofing that protects
against cold, wind and rain but admits light. A verandah may be roofed with material that
protects against sunlight but admits the other elements.

The characteristics of a roof are dependent upon the purpose of the building that it covers, the
available roofing materials and the local traditions of construction and wider concepts of
architectural design and practice and may also be governed by local or national legislation.

The elements in the design of a roof are :-

        the material
        the construction
        the durability

The material of a roof may range from banana leaves, wheaten straw or seagrass to lamininated
glass, aluminium sheeting and precast concrete. In many parts of the world ceramic tiles have
been the predominant roofing material for centuries.

The construction of a roof is determined by its method of support and how the underneath space
is bridged and whether or not the roof is pitched. The pitch is the angle at which the roof rises
from its lowest to highest point. Most domestic architecture, except in very dry regions, has roofs
which are sloped, or pitched. The pitch is partly dependent upon stylistic factors, but has more to
do with practicalities. Some types of roofing, for example thatch, require a steep pitch in order to
be waterproof and durable.[1] Other types of roofing, for example pantiles, are unstable on a
steeply pitched roof but provide excellent weather protection at a relatively low angle. In regions
where there is little rain, an almost flat roof with a slight run-off provides adequate protection
against an occasional downpour.

The durability of a roof is a matter of concern because the roof is often the least accessible part
of a building for purposes of repair and renewal, while its damage or destruction can have
serious effects.

       1 Parts of a roof
            o 1.1 Support
                      1.1.1 Construction of a ridged roof
            o 1.2 Outer layer
            o 1.3 Insulation
            o 1.4 Drainage
            o 1.5 Solar roofs
       2 Roof shapes
       3 Commercially available roofing materials
       4 Gallery of significant roofs
       5 See also
       6 References
       7 Further reading
       8 External links

[edit] Parts of a roof
There are two parts to a roof, its supporting structure and its outer skin, or uppermost
weatherproof layer. In a minority of buildings, the outer layer is also a self-supporting structure.

The roof structure is generally supported upon walls, although some building styles, for example,
geodesic and A-frame, blur the distinction between wall and roof.

[edit] Support

The roof of a library, Sweden.

The supporting structure of a roof usually comprises beams that are long and of strong, fairly
rigid material such as timber, and since the mid 19th century, cast iron or steel. In countries that
use bamboo extensively, the flexibility of the material causes a distinctive curving line to the
roof, characteristic of Oriental architecture.

Timber lends itself to a great variety of roof shapes. Moreover, because timber can be worked in
a variety of ways, the timber structure can fulfil an aesthetic as well as practical function, when
left exposed to view.

Stone lintels have been used to support roofs since prehistoric times, but cannot bridge large
distances. The stone arch came into extensive use in the Ancient Roman period and in variant
forms could be used to span spaces up to 140 feet across. The stone arch or vault, with or without
ribs, dominated the roof structures of major architectural works for about 2,000 years, only
giving way to iron beams with the Industrial Revolution and the designing of such buildings as
Paxton's Crystal Palace, completed 1851.

With continual improvements in steel girders, these became the major structural support for large
roofs, and eventually for ordinary houses as well. Another form of girder is the reinforced
concrete beam, in which metal rods are encased in concrete, giving it greater strength under

[edit] Construction of a ridged roof

A simple ridged roof consists of inclined rafters that rest on horizontal wall-plates on top of each
wall. The top ends of the rafters meet at the horizontal ridge plate or ridge beam. Horizontal
purlins are fixed to the rafters to support the roof covering. Heavier under purlin are used to
support longer rafter spans. Tie beams or ceiling joists, are connected between the lower ends of
opposite rafters to prevent them from spreading and forcing the walls apart. Collar beams or
collar ties may be fixed higher up between opposite rafters for extra strength.[2]

Roof under construction in high wind area.

The rafters, tie beams and joists serve to transmit the weight of the roof to the walls of the
building. There are a number of structural systems employed to facilitate this, including the use
of wall-plates set at the top of the wall, hammer-beams, which spread the weight down the wall
and create an equilibrium between outward and upward thrust, king posts which transfer the
weight of the roof ridge, and various types of trusses.

In cyclone and hurricane prone areas the main engineering consideration is to hold the roof down
during severe storms. Every component of the roof (as of course the rest of the structure) has to
withstand the uplift forces of high wind speeds. Modern roofing technologies in hurricane areas
includes the purpose-made steel hook bracket which is bolted to the truss with M16 bolt. The
bracket is bolted to an M16 bolt cast in situ, embedded 300 mm into the reinforced concrete
block wall. This system is typically in place every 900 mm around perimeter.

[edit] Outer layer

Cameroon, a wattle and daub house, roofed with banana leaves.
Japan, rice straw thatch

England, slate

Hungary, terracotta tiles

Namibia, metal roof.

This part of the roof shows great variation dependent upon availability of material. In simple
vernacular architecture, roofing material is often vegetation, such as thatches of different
materials, the most durable being sea grass with a life of perhaps 40 years. In areas with an
abundance of timber, wooden shingles are used, while in some countries the bark of certain trees
can be peeled off in thick, heavy sheets and used for roofing.

The 20th century saw the manufacture of composition shingles which can last from a thin 20-
year shingle to the thickest which are limited lifetime shingles, the cost depending on the
thickness and durability of the shingle. When a layer of shingles wears out, they are usually
stripped, along with the underlay and roofing nails, allowing a new layer to be installed. An
alternative method is to install another layer directly over the worn layer. While this method is
faster, it does not allow the roof sheathing to be inspected and water damage, often associated
with worn shingles, to be repaired. Having multiple layers of old shingles under a new layer
causes roofing nails to be located further from the sheathing, weakening their hold. The greatest
concern with this method is that the weight of the extra material could exceed the dead load
capacity of the roof structure and cause collapse.

Slate is an ideal, and durable material, while in the Swiss Alps roofs are made from huge slabs of
stone, several inches thick. The slate roof is often considered the best type of roofing. A slate
roof may last 75 to 150 years, and even longer. However, slate roofs are often expensive to
install - in the USA, for example, a slate roof may have the same cost as the rest of the house.
Often, the first part of a slate roof to fail is the fixing nails; they corrode, allowing the slates to
slip. In the UK, this condition is known as "nail sickness". Because of this problem, fixing nails
made of stainless steel or copper are recommended, and even these must be protected from the
Roofs made of cut turf (Green roofs have good insulating properties and, known as Green roofs,
are increasingly encouraged as a way of "greening" the Earth. Adobe roofs are roofs of clay,
mixed with binding material such as straw or animal hair, and plastered on lathes to form a flat
or gently sloped roof, usually in areas of low rainfall.

In areas where clay is plentiful, roofs of baked tiles have been the major form of roof. The
casting and firing of roof tiles is an industry that is often associated with brickworks. While the
shape and colour of tiles was once regionally distinctive, now tiles of many shapes and colours
are produced commercially, to suit the taste of the purchaser.

Sheet metal in the form of copper and lead has also been used for many hundreds of years. Both
are expensive but durable, the vast copper roof of Chartres Cathedral, oxidised to a pale green
colour, having been in place for hundreds of years. Lead, which is sometimes used for church
roofs, was most commonly used as flashing in valleys and around chimneys on domestic roofs,
particularly those of slate. Copper was used for the same purpose.

In the 19th century, iron, electroplated with zinc to improve its resistance to rust, became a light-
weight, easily-transported, waterproofing material. While its insulating properties were poor, its
low cost and easy application made it the most accessible commercial roofing, world wide. Since
then, many types of metal roofing have been developed. Steel shingle or standing-seam roofs last
about 50 years or more depending on both the method of installation and the moisture barrier
(underlayment) used and are between the cost of shingle roofs and slate roofs. In the 20th
century a large number of roofing materials were developed, including roofs based on bitumen
(already used in previous centuries), on rubber and on a range of synthetics such as thermoplastic
and on fibreglass.

[edit] Insulation

Snow on the roof of houses in Poland.

Some roofing materials, particularly those of natural fibrous material, such as thatch, have
excellent insulating properties. For those that do not, extra insulation is often installed under the
outer layer. In developed countries, the majority of dwellings have a ceiling installed under the
structural member of the roof. The purpose is to insulate against heat and cold, noise, dirt and
often from the droppings and lice of birds who frequently choose roofs as nesting places.

Other forms of insulation are felt or plastic sheeting, sometimes with a reflective surface,
installed directly below the tiles or other material; synthetic foam batting laid above the ceiling
and recycled paper products and other such materials that can be inserted or sprayed into roof

So called Cool roofs are becoming increasingly popular, and in some cases are mandated by
local codes. Cool roofs are defined as roofs with both high reflectivity and high emissivity.
[edit] Drainage

The flat roofs of the Middle East, Israel.

The steeply pitched, gabled roofs of Scandinavia.

The overhanging eaves of China.

The primary job of most roofs is to keep out water. The large area of a roof repels a lot of water,
which must be directed in some suitable way, so that it does not cause damage or inconvenience.

Flat roof of adobe dwellings generally have a very slight slope. In a Middle Eastern country,
where the roof may be used for recreation, it is often walled, and drainage holes must be
provided to stop water from pooling and seeping through the porous roofing material.

Similar problems, although on a very much larger scale, confront the builders of modern
commercial properties which often have flat roofs. Because of the very large nature of such
roofs, it is essential that the outer skin is of a highly impermiable material. Most industrial and
commercial structures have conventional roofs of low pitch.

In general, the pitch of the roof is proportional to the amount of precipitation. Houses in areas of
low rainfall frequently have roofs of low pitch while those in areas of high rainfall and snow,
have steep roofs. The longhouses of Papua New Guinea, for example, being roof-dominated
architecture, the high roofs sweeping almost to the ground. The high steeply-pitched roofs of
Germany and Holland are typical in regions of snowfall. In parts of the North America such as
Buffalo USA or Montreal Canada, there is a required minimum slope of 6 inches in 12 inches, a
pitch of 45 degrees.

There are regional building styles which contradict this trend, the stone roofs of the Alpine
chalets being usually of gentler incline. These buildings tend to accumulate a large amount of
snow on them, which is seen as a factor in their insulation. The pitch of the roof is in part
determined by the roofing material available, a pitch of 3/12 or greater slope generally being
covered with asphalt shingles, wood shake, corrugated steel, slate or tile.

The water repelled by the roof during a rainstorm is potentially damaging to the building that the
roof protects. If it runs down the walls, it may seep into the mortar or through panels. If it lies
around the foundations it may cause seepage to the interior, rising damp or dry rot. For this
reason most buildings have a system in place to protect the walls of a building from most of the
roof water. Overhanging eaves are commonly employed for this purpose. Most modern roofs and
many old ones have systems of valleys, gutters, waterspouts, waterheads and drainpipes to
remove the water from the vicinity of the building. In many parts of the world, roofwater is
collected and stored for domestic use.

Areas prone to heavy snow benefit from a steel roof because their smooth surfaces shed the
weight of snow more easily and resist the force of wind better than a wood shingle or a concrete
tile roof.

        See also: Trade hall roof collapse in Katowice, Poland and Bad Reichenhall ice rink roof collapse

[edit] Solar roofs

Green roof with solar panels, Findhorn.

Newer systems include solar shingles which generate electricity as well as cover the roof. There
are also solar systems available that generate hot water or hot air and which can also act as a roof
covering. More complex systems may carry out all of these functions: generate electricity,
recover thermal energy, and also act as a roof covering.

There are different ways that solar systems can be integrated with roofs:

       integrated in the covering of pitched roofs, e.g. solar shingles.
       mounted on an existing roof, e.g. solar panel on a tile roof.
       integrated in a flat roof membrane using heat welding, e.g. PVC.
       mounted on a flat roof with a construction and additional weight to prevent uplift from wind.

[edit] Roof shapes

Flat roof, Western Australia.
Mansard roof on a county jail, Mount Gilead, Ohio.

These include:

       flat
       lean-to
       Skillion roof single-sloped, lean to, or shed roof
       ridged
             o pitched or gabled
                      shaped gable
                      Dutch gable - a hybrid of hipped and gable
                      crow-stepped gable (also called corbie step) gable
                      salt-box
             o saddleback (a gabled roof atop a tower)
             o hip roof includes a sketch of a Dutch gable (Australian terminology)
             o half-hipped
             o mansard
             o gambrel
             o pavilion
       conical
       domical
       pyramidal
       saw-tooth

Temple roof Chang Mai, Thailand with a decorated gable end and ceramic tile covering.

Reed thatch on the island of Sylt.

A roof tiled in imitation of thatch at Croyde, North Devon, England

Wooden shingles.
USA, bitumen

[edit] Commercially available roofing materials
The weather proofing material is the topmost or outermost layer, exposed to the weather. Many
different kinds of materials have been used as weather proofing material:

      Thatch is roofing made of plant material, in overlapping layers.[4]
            o Wheat Straw, widely used in England, France and other parts of Europe.
            o Seagrass, used in coastal areas where there are esturies such as Scotland. Has a longer
               life than straw. Claimed to have a life in exccess of 60 years.[5]
      Shingles, called shakes in North America. Shingles is the generic term for a roofing material that
       is in many overlapping sections, regardless of the nature of the material. The word is also used
       specifically to denote shingles made of wood.
            o Redcedar. Life expectancy, up to 30 years. However, young growth redcedar has a
               short life expectancy. High cost. Should be allowed to breathe. [7]
            o Hardwood. Very durable roofing found in Colonial Australian architecture, its use now
               limited to restorations.
            o Slate. High cost with a life expectancy of up to 200 years. Being a heavy material, the
               supporting structure must be very robust.
            o Ceramic tile. High cost, life of up to 100 years.
                      Imbrex and tegula, style dating back to ancient Greece and Rome.
            o Metal shakes or shingles. Long life. High cost, suitable for roofs of 3/12 pitch or greater.
               Because of the flexibility of metal, they can be manufactured to lock together, giving
               durability and reducing assembly time.[10]
            o Mechanically seamed metal. Long life. High cost, suitable for roofs of low pitch such as
               0.5/12 to 3/12 pitch.
            o Concrete, usually reinforced with fibres of some sort.
            o Asphalt shingle, made of bitumen embedded in an organic or fiberglass mat, usually
               covered with colored, man-made ceramic grit. Cheaper than slate or tiles. Various life
               span expectancies.
            o Asbestos shingles. Very long lifespan, fireproof and low cost but now rarely used
               because of health concerns.[11][12]
      Membrane. membrane roofing is in large sheets, generally fused in some way at the joints to
       form a continuous surface.
            o Thermosetting plastic (e.g. EPDM rubber). Synthetic rubber sheets adhered together
               with contact adhesive or tape. Primary application is big box store with large open areas
               and little vertical protrusions.
            o Thermoplastic (e.g. PVC, TPO, CSPE). Plastic sheets welded together with hot air creating
               one continuous sheet membrane. Can be rewelded with the exception of CSPE. Lends
               itself well to both big box and small roof application because of its hot air weldability.
            o Modified bitumen - heat welded, asphalt adhered or installed with adhesive. Asphalt is
               mixed with polymers such as APP or SBS, then applied to fiberglass and/or polyester
               mat, seams sealed by locally melting the asphalt with heat, hot mopping of asphalt, or
               adhesive. Lends itself well to all applications.
           o   Built-Up Roof - Multiple plies of asphalt saturated organic felt or coated fiberglass felts.
               Plies of felt are adhered with hot asphalt, coal tar pitch or adhesive.
           o   Sprayed-in-Place Polyurethane Foam (SPUF) - Foam sprayed in-place on the roof, then
               coated with a wide variety of coatings, or in some instances, covered with gravel.
           o   Fabric
                    polyester.
                    PTFE, (synthetic fluoropolymer) embedded in fibreglass.

Corrugated iron sheeting a house under construction in Northern Australia. Shows two gables and
external cyclonic fastenings.

      Metal roofing. Generally a relatively inexpensive building material.
          o Galvanised steel frequently manufactured with wavy corrugations to resist lateral
               flexing and fitted with exposed fasteners. Widely used for low cost and durability. Sheds
               are normally roofed with this material. Known as Gal iron or Corro, it was the most
               extensively used roofing material of 20th century Australia, now replaced in popularity
               by steel roofing coated with an alloy of zinc and aluminium, claimed to have up to four
               times the life of galvanized steel. [13]
          o Standing-seam metal with concealed fasteners.
          o Mechanically seamed metal with concealed fasteners contains sealant in seams for use
               on very low sloped roofs.
          o Flat-seam metal with soldered seams.

[edit] Gallery of significant roofs

                                               The hip roofs and                  The polychrome tiles of
Imbrex and tegula tiles on the The marble dome
                                               dormers of Chateau                 the Hospice of Beaune,
dome of Florence Cathedral. of the Taj Mahal.
                                               Chenonceau.                        France.

The copper roof of Speyer       The lead roof of                                  The glazed ceramic
                                                       The glass roof of the
Cathedral, Germany. photo       King's College                                    tiles of the Sydney
                                                       Grand Palais, Paris.
Wolfi.                          Chapel, England.                                  Opera House.
New Urbanism

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