Engineered Wood Products
(EWP)
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Definition
A range of derivative wood products which are manufactured by
binding strands, particles, fibers or veneers of wood together with
adhesives to form a composite material.
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Characteristics
• Engineered wood products (EWP) are made form the same
hardwoods and softwoods as dimensioned lumber.
• Similar products can be manufactured from other lignin
containing materials such as straw, stalks or sugar cane
residue.
• Engineered wood products can be used in almost every
situation to replace dimension lumber.
• These products are engineered to precise design specifications,
which are tested to meet national or international standards.
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Advantages of EWP
• EWP can be designed to meet application-specific performance
and environmental requirements.
• Large panels of EWP can be constructed from small trees
and/or small pieces of wood.
• Engineered wood products are often stronger
• More dimensionally stable.
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Disadvantages of EWP
• More expensive to produce.
• The adhesives that are used can be toxic and a pollution
concern.
• Adhesives can outgas.
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Common EWP
• Glulam
• I-Joist
• Structural Composite Lumber
• Orientated strand board
• Plywood
• Siding
• Specialty wood products
• Nonstructural engineered wood products
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EWP-Glulam
• Glulam is a stress-rated engineered wood
product comprised of wood laminations, or
"lams," that are bonded together with
strong, waterproof adhesives.
• Glulam components can be a variety of
species, and individual "lams" are typically
two inches or less in thickness.
• Uses
– Vertical columns
– Horizontal beams
– Complex shapes
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EWP—Glulam—cont.
Complex shapes:
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EWP-I Joist
• "I"-shaped engineered wood
structural members that offer
strength, versatility and economy for
use in residential and light
commercial applications.
• I-joists are comprised of top and
bottom flanges of various widths
united with webs of various depths.
• The flanges resist common bending
stresses, and the web provides
outstanding shear performance.
• EWP I-joists can be closed or open
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EWP- Structural Composite Lumber
• Structural composite lumber (SCL) is a
family of engineered wood products
created by layering dried and graded
wood veneers or flakes with waterproof
adhesive into blocks of material known
as billets.
• SCL includes:
– Laminated veneer lumber (LVL)
– Laminated strand lumber (LSL)
– Oriented strand lumber (OSL)
• Cured in a controlled process, SCL is
typically available in various thicknesses
and widths and is easily worked in the
field using conventional construction
tools.
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EWP-Oriented Stand Board
(OSB)
• OSB is manufactured from waterproof
heat-cured adhesives and rectangular
shaped wood strands that are arranged in
cross-oriented layers, similar to plywood.
• This results in a structural engineered
wood panel that shares many of the
strength and performance characteristics
of plywood.
• Produced in huge, continuous mats, OSB
is a solid panel product of consistent
quality with no laps, gaps or voids.
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Plywood
• Laminated product.
• Thin sheets of veneers (piles)
are peeled from a log.
• Each pile is rotated 90 degrees. 1http://www.apawood.org
• The piles are glued and bonded
under heat and pressure. • Most common construction is
three, five or seven piles.
• Most common size is 4 ft x 8 ft.
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Types of Plywood
• Types of plywood are categorized by six (6) grades of the
veneers and four (4) bonding types.
• Six (6) veneer grades (Fig 40-11):
1. A: smooth, paintable. No more than 18 neatly made repairs
2. B: Solid surface. Repairs and tight knots up to 1 inch permitted
3. C: Tight knots to 1-1/2 inches. Discoloration and sanding defects,
limited splits
4. C (Plugged): Improved C veneer.
5. D: Knots and knotholes to 2-1/2 inches. Limited splits allowed.
Limited to interior panels.
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Four (4) Plywood-Bonding Types
• Interior Plywood:
– Plywood for interior use only are made from various hardwood and
softwood species, and can be used only in interior applications such as wall
sheathing, furniture (where exposure to moisture is limited), cabinetry and
the like.
– Interior plywood is available in most grades, as well as a number of
hardwood species such as birch, oak and cherry.
• Exterior Plywood:
– The most common type of plywood, readily available at home centers.
– The glues used in exterior plywoods are much more resistant to moisture
than interior plywoods.
– Once again, nearly all grades are available, with A-C, B-C and CDX the
most common. Numerous hardwood species are also available in exterior
varieties.
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Plywood Bonding Types-cont.
• Marine Plywood:
– When moisture resistance is a priority, look into marine plywood.
– This type uses the best adhesives and is manufactured to the
highest standards.
– It also is most commonly graded as A-A, with two top grade faces,
but is limited in the hardwood choices that are practical for use in
marine settings.
• Structural Plywood:
– When the appearance of the face is of lesser concern than the
strength and stability of the material, structural plywood will typically
be the choice.
– The resins used to adhere the plies are designed for extra strength
to avoid separating of the layers.
– Structural plywood is seldom found in a grade higher than C-D. It is
commonly used in concrete forms on construction sites.
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EWP-Siding
A single layer of rack-resistant panel siding delivers an
attractive exterior appearance while eliminating the labor
and materials cost of installing separate structural
sheathing.
Engineered siding
products are a
popular alternative
to wood, vinyl, and
aluminum siding.
Engineered wood products may include cement,
or other materials, to produce an authentic
appearance without the maintenance and
expense of natural wood.
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EWP - Specialty Wood Products
• Engineered wood can be used in thousands of different
applications.
• Some of these applications are made possible though the
creations and innovations manufacturers
• Engineered wood products with unique characteristics are
suitable for building diverse end-use products such as boats,
truck bodies and even upholstered furniture.
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EWP - Specialty Wood Products—cont.
• FRP (Fiberglass-reinforced-
plastic) plywood
• SIP (Structural Insulated Panels)
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EWP- Nonstructural
Engineered Wood Products
• Medium density fiberboard (MDF)
• Particle board
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Medium Density Fiberboard (MDF)
• MDF is manufactures by breaking
down softwood by rubbing it into
wood fibers.
• The fibers are combined with wax
and resin, formed into panels and
solidified with temperature and
pressure.
• It has higher density than normal
particleboard.
Biggest concern is the use of formaldehyde resins.
Will disintegrate with water.
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MDF Characteristics
• Should not be used outdoors because it will swell upon contact
with water.
• Consistent structure
• Easy to machine.
• Can also be used with veneers.
• Good material for cabinets and acoustic enclosures.
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Particleboard
• Also called chipboard.
• Manufactured from wood
particles larger than what is used
for MDF.
• Characteristics
Cheaper, denser and more uniform the dimensioned
lumber and plywood.
Best used when appearance and strength are less
important than cost.
May be veneered
Prone to expansion a discoloration due to moisture.
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Roofing & Siding
• Manny different materials can be used, but steel and aluminum
sheets are popular for agricultural buildings.
– Different thicknesses
– Different quality of paint/galvanizing.
• Roofing materials (Fig 40-15, pg 583)
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Siding Materials
• Popular siding materials for Ag buildings:
– Wood
– Steel
– Aluminum
– PVC
– Polypropylene
– Composite
– Masonry
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Questions
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