Room Additions

St. Louis County Department of Public Works Division of Code Enforcement HABITABLE RESIDENTIAL ADDITIONS BUILDING PERMIT REQUIREMENTS This guideline is intended to provide the homeowner/contractor with the basic information needed to apply for a building permit to construct most simple residential room additions. For larger more complex additions having several rooms and for additions including kitchens or basements, it is recommended that the homeowner/ contractor also obtain a copy of St. Louis County's "Single-Family Dwelling Checklist" to aid in the preparation of plans required for submittal. 1. 2. Fill out and sign application for a building permit. Submit four (4) separate copies of your plot (site) plan showing the following: An accurate, legible drawing, drawn to scale that clearly depicts the dimensions and angles of the property boundary lines. The location of all building setback lines and easements. The size and location of all existing structures on the lot (including the new addition), the dimensions of the addition, and its distance from the lot lines and from adjacent structures on the lot. Grade shall be noted to slope away from foundation a minimum of a 6” drop within the first 10’ or to a swale. Indicate present and proposed finished grades at each corner of the addition in relation to the established first floor level. Direction of drainage shall be indicated with arrows on the site plan. Show location of existing on-site sanitary sewage disposal system and well if applicable. A wall of a room addition that is less than 3’ to the lot line shall be a one hour fire rated exterior wall with no openings. 3. Obtain zoning approval from the Department of Public Works, if an unincorporated area, or from municipality. In municipalities site plans must be marked "Approved" and Municipal Approval Form submitted with application. Submit four (4) separate complete sets of detailed building construction plans drawn to scale and containing the following: Foundation Plan @ 1/4" = 1'-0" Floor plans @ 1/4" = 1'-0" Building Elevations @ 1/4" = 1'-0" ADDITION Rev. 09/01/06 -1BP1008 4. Wall Section(s) @ 3/4" = 1'-0" Other Sections & Details @ 3/4" = 1'-0" Note: Include at least four (4) feet of the existing house on both the floor plans and elevations. Identify each existing room by name, locate existing door and window openings, and indicate any changes needed to the existing house and house wall as a result of the proposed addition. Include one of the following in your plan submittal depending on choice of floor and/or roof framing systems: (1) (2) If by conventional method, indicate size and spacing of floor joists, rafters, ceiling joists, and/or ties on the sections and details included in the plans submitted. If by the "truss" method, submit four (4) copies of the engineer's sealed truss plan which can be obtained from the lumber dealer or the "truss" fabricator. Trusses to comply with AFPA NDS-91 and TPI 1-95. 5. If a pre-fab fireplace or wood burning stove is to be installed include a section drawing at 3/4" = 1'-0" scale in your plan submittal and also provide one (1) copy of the manufacturer’s installation instructions. (The unit shall be certified or tested by a nationally recognized and approved testing agency and bear that agency's label.) If the finished area of the addition exceeds 25% of the finished area of the existing house the following must be provided with your submittal: Four (4) copies of the heating and air conditioning plans for the addition (separate system) or for entire house including proposed addition (combined system). Two (2) copies of heat loss/heat gain calculations for the addition (separate system) or for the entire house including proposed addition (combined system). 6. 7. When the existing house is served by a septic or other o n-site sewage disposal system, new bedroom additions, or any habitable room addition which could be converted to use as a bedroom, requires that the adequacy of the septic system to handle the additional potential load, be verified by the Plumbing Inspection Section. Refer to separate handouts regarding rules, regulations and procedures for septic systems. All plumbing and electrical work must be performed in accordance with St. Louis County Codes and Ordinances by licensed master plumbers, licensed electrical contractors, or a preauthorized homeowner who by examination has demonstrated the knowledge and ability to perform the work. All mechanical work must be performed by a registered financial responsible (bonded and insured) or licensed contractor authorized to do mechanical work. Homeowners may perform their own mechanical work within their own dwelling with no requirement to be registered or licensed. It is the applicants’ responsibility to check with other agencies or jurisdictions concerning their requirements that may be affected by the proposed addition. Contact the appropriate agencies such as the Highway Department, Fire Department, Municipality, Sewer District, ADDITION Rev. 09/01/06 -2BP1008 8. 9. Subdivision Trustees, etc. 10. Issuance of a building permit for the project does not authorize construction access to the work site. If the existing driveway entrance to the site is unavailable for construction access, the owner/contractor shall apply for a permit to construct a temporary entrance from the owner of the Right-of-Way. For additional information regarding the criteria in this handout, please contact: Contact (314) 615-5184 (314) 615-7155 (314) 615-3763 (314) 615-5485 (888) 275-6636 (314) 615-8517 Municipality General Information Permit Processing Zoning Review Building Plan Review Right-of-Way Owner State County Municipality Refer to the attached drawings and the following listing of common code requirements pertaining to most simple residential room additions: FOOTINGS BEARING ON UNDISTURBED SOIL 2000psf BEARING CERTIFIED BY A MISSOURI PROFESSIONAL ENGINEER1 Framed Wall Framed Wall w/Brick Veneer 12” 24” 21” 30” 32” 36” Framed Wall 12” 16” 12” 18” 17” 21” Framed Wall w/Brick Veneer 12” 18” 16” 23” 24” 27” 1 Story slab on Grade 1 Story w/Basement 2 Story slab on Grade 2 Story w/Basement 3 Story Slab on Grade 3 Story w/Basement 12” 21” 15” 24” 23” 27” 1. Documented by a letter/statement sealed by a Missouri Professional Engineer. The foundation wall shall set in the middle of the footing. The footing thickness shall be a minimum of 6 inches but not less than the distance the footing extends horizontally past the face of the foundation wall. The bottom of all footings must be a minimum of 2'-6" below finished grade and bear on undisturbed soil or prepared fill. ADDITION Rev. 09/01/06 -3BP1008 FOUNDATION WALLS Minimum 8" thick keyed to footing and extending minimum 8" above finished grade. 1/2" round anchor bolt, placed a maximum of 6'-0" o.c. and at corners or ends, set a minimum of 7" into concrete required for anchoring of sill plates (2x4 minimum) around entire foundation with 1½” washers and nuts for a room addition serving an one and two family dwelling. One should use 3/16 x 2 x 2 washers for a room addition serving a townhouse (3 or more attached dwellings). Sill plates to be grouted level or have sill sealer with approved shim materials and methods. CONCRETE Minimum thickness of concrete floor slabs supported directly on the ground is 3 -1/2". The slab shall be placed over a minimum 4" base course of gravel or crushed stone and a 6 mil. polyethylene film vapor barrier. Minimum compressive strength of concrete shall be: 2500 psi - floor slabs 3000 psi - foundation walls and footings 3500 psi - porches, walks, patios and steps Concrete for all foundation walls, porches, walks, patios and steps shall be air-entrained. STRUCTURAL FRAMING Indicate size, weight and spacing of all steel beams and columns. Indicate size, fiber stress, type and grade of lumber of all wood beams and columns. Identify interior bearing wall locations. Indicate direction of floor joists, size, spacing, fiber stress, type and grade of lumber shown. Exterior wall framing to be constructed in accordance with the following Table. The grade of studs shall be standard grade or better. Maximum spacing when supporting roof and ceiling only (inches) 24 24 Maximum spacing when supporting one floor, roof and ceiling (inches) 16 24 Maximum spacing when supporting two floors, roof and ceiling (inches) --16 Maximum spacing when supporting one floor only (inches) 24 24 STUD SIZE (inches) 2x4 2x6 Laterally unsupported stud height (feet) 10 10 WALL BRACING All new walls of the room addition shall be braced using the attached “Room Addition Bracing Guideline for One and Two Family Dwellings or Townhouses” or you may brace the room addition using one of the following documents found at www.stlouisco.com/pubworks: • • Appendix A, One and Two Family Wind Bracing Guideline. This document may be used for bracing the new walls of an addition to a one and two family dwelling. Appendix B, Townhouse Seismic Bracing Guideline. This document may be used for bracing the new walls of an addition to a townhouse (3 or more attached dwelling units each with their -4BP1008 ADDITION Rev. 09/01/06 own independent means of egress. Openings complying with the following limitations will be permitted in an existing exterior wall without a structural analysis of the existing house: a. Any existing opening, including existing openings being modified provided the opening width and headers/lintels above are not being modified. Any opening or accumulative width of multiple openings 6’ or less in width may be made in an existing exterior wall without a structural analysis addressing the longitudinal (racking) loading on the existing wall. An opening or accumulative width of multiple openings exceeding 6’ but less than or equal to 20’ in width may be made in an existing exterior wall without a structural analysis addressing the longitudinal (racking) loading on the existing wall if the opening(s) width is less than 50% of the braced wall line. A braced wall line is typically a straight wall but could include some offsets. A single offset of 4 feet or multiple offsets each 4 feet or less as long as the sum of all the offsets is 8 feet or less may all be part of single braced wall line. (See Figure1) b. c. A structural analysis of the existing structure is required in the following situations: d. e. For all openings larger than described in b & c above. The addition is placed above a partial or full wood framed story. A partial wood framed story is a story constructed partially of wood stud wall framing and some other wall construction method such as concrete or masonry. The structural analysis, if required, shall include four sets of structural details and one set of structural calculations properly signed, sealed and dated by a Missouri Registered Design Professional (Engineer or Architect) utilizing the International Building Code/2003. As an option, the design professional may provide a properly signed, sealed, and dated structural certification that the existing building with the proposed modifications complies with the lateral bracing provisions of Section R602.10 of the 2003 edition of the International Residential Code or Section 2305 of the 2003 edition of the International Building Code. All room additions shall be supported on a continuous foundation and footing. Four sets of structural details and one set of structural calculations properly signed, sealed and dated by a Missouri Registered Design Professional are required to address lateral bracing of any new addition proposed to be constructed without a continuous foundation such as constructing an addition over an elevated deck supported by columns and piers. ADDITION Rev. 09/01/06 -5- BP1008 Figure 1 ROOF FRAMING For conventional framed roof systems, indicate size, spacing, fiber stress, type and grade of wood for roof rafters and ceiling joists. Indicate roof pitch. Show rafter and ceiling joist framing layout on plans. Trussed roofs and/or floors shall have sealed truss plans indicating spacing and roof pitch for each span utilized. Include girder trusses if utilized. Show truss framing layout including girder locations on the plans. All trusses shall comply with TPI 1-2002. All roof framing shall be designed to support the following minimums: Top chord of trusses or roof rafter: Snow Load 20 lb. per sq. ft. Dead Load Use actual dead load.(Note: Dead load must include 2 layers of roofing membrane ADDITION Rev. 09/01/06 -6- BP1008 Ceiling joists or Bottom chord of trusses: Use a live load of 20 lb. per sq. ft when there is attic storage. Use 10 lb per sq. ft. live load where there is no attic storage. Dead load—use actual dead load. Note: The live load design on the ceiling joist or bottom chord of a truss shall not be required if all of the following conditions are adhered to: a. Attics with drywall ceilings below that are accessed only by a 22" x 30" scuttle opening without a pull-down stairway. b. Warning signs attached to the trusses on each side of the scuttle opening at least 36" above the bottom chord and within 18" of the edge of the opening. The signs shall be constructed of metal or other approved durable materials suitable for the location and be a minimum of 40 sq. inches in area with 3/4" minimum high letters on a contrasting background that reads “WARNING-TRUSSES NOT DESIGNED FOR ATTIC STORAGE”. c. Attic areas over garage areas with drywall ceilings shall also be provided with a horizontal railing attached to the trusses on each side of the scuttle opening at least 24" and not more than 36" above the bottom chord. The railing is intended to be an obstruction to easy access for storage and shall be constructed of either 1x4's, 2x4's or 3/8"x 6" plywood. It may be shop or field applied. Where trusses or rafters are spaced 24" o.c., roof panels shall be a minimum of 15/32” thick sheathing without edge support or a minimum of 3/8" thick (minimum 24/0 span rated) sheathing with edge support. Edge support shall be tongue-and-groove edges, panel edge clips (at midpoint between each support) or 2x lumber blocking. ROOFING Class A, B, or C roofing shall be required where the edge of the roof is less than 3’ to the property line. Underlayment for asphalt shingles: Slopes of 2:12 to less than 4:12 shall be protected with two layers of underlayment. Apply a 19” strip of underlayment felt parallel with and starting at the eaves, fastened sufficiently to hold into place. Starting at the eave, apply 36” wide sheets of underlayment. Successive 36” wide sheets of underlayment shall overlap the previous 36” wide sheet by 19”. All underlayment shall be fastened sufficiently to hold into place. Slopes equaling or exceeding 4:12 shall be protected with one layer of underlayment. Underlayment shall be applied shingle fashion, parallel to and starting from the eave and lapped 2”, fastened sufficiently to hold in place. End laps shall be offset by 6’. All underlayment to be a minimum of Type I per ASTM D226-97a or Type I per ASTM D486988(1993)e (Type I is commonly called No. 15 asphalt felt.) Indicate corrosion-resistant flashing at all wall and roof intersections, changes in roof slope or ADDITION Rev. 09/01/06 -7BP1008 direction, around all roof openings, intersections with chimneys, intersection of exterior walls and porches and decks, etc. Valley flashing shall be installed per R905.2.8.2 Built-up membrane roof slope is 1/4:12 with approved low-slope roof covering materials. A CoalTar built-up membrane may be installed on 1/8:12 slope. Mineral-surfaced roll roofing shall conform to ASTM D 224, D 249, D 371, D 3909. It shall not be installed on roof slopes below 1:12. SMOKE DETECTORS AC powered, U.L. listed smoke detectors with battery backup shall be placed throughout the dwelling unit as noted below unless already existing. All detectors within the dwelling shall be interconnected and hard wired so that the activation of any alarm will sound all alarms throughout the house. Exception: Detector locations in existing areas shall not be required to be interconnected and hard wired where the alterations or repairs do not result in the removal of interior wall or ceiling finishes exposing the structure, unless there is an attic, crawl space, or basement available which could provide access for hard wiring and interconnection without the removal of interior finishes. Smoke detectors shall be placed in the following locations: Floor levels with bedrooms: A smoke detector is required in each bedroom and one centrally located detector is required outside of a group of bedrooms in the hall way. Floor level without bedrooms: A smoke detector is required adjacent to the stair. WALLS Approved water resistant gypsum backer board is required in bathtub and shower compartments. Interior finish materials shall not have a flame spread rating exceeding 200. Brick veneer and masonry walls require corrosion-resistant corrugated sheet metal wall ties minimum 22 ga. by 7/8" wide at 24" o.c. vertically and 24" o.c. horizontally (maximum) and shall support no more than 2.67 square feet of wall area (2 square feet maximum on an addition serving a townhouse). 1" minimum air space between brick and sheathing required. Brick veneer anchors around openings larger than 16” in either direction shall be spaced a maximum 3’-0” o.c. maximum around the perimeter of and within 12” of the opening. Brick veneer walls require weepholes at least 3/16" dia. spaced less than 33" apart. Weather- resistant sheathing paper (Asphalt saturated felt 14# per square otherwise known as Type I felt, Tyvek, Typar, or other approved weather resistant material) shall be installed under certain types of siding and brick/stone veneer listed in Table R703.4 Exceptions: a. For masonry veneer, a weather-resistant membrane is not required over water repellent sheathing materials when a 1” air space is provided between ADDITION Rev. 09/01/06 -8BP1008 b. the veneer and the sheathing. When the 1” space is filled with mortar, a weather-resistant membrane is required over the sheathing. Vinyl or horizontal aluminum siding. INSULATION Indicate type, thickness and "R" values of all insulating materials. Foam plastic insulation shall be separated from the interior of the building by 1/2" gypsum wallboard. FIRE BLOCKING Top and bottom of all conventional, double stud, furred spaces, and staggered stud frame walls are to be fireblocked vertically at the ceiling and floor levels and horizontally at intervals not exceeding 10’. Fireblocking required at all soffits and dropped ceilings. Fireblocking required between stairway stringers at the top and bottom of the run. Enclosed accessible spaces under stairs shall have walls, under stair surface and any soffits protected on the enclosed side with ½ “ gypsum board. Fireblocking required around vent, pipe, and duct penetrations of ceilings and floors. Fireblocking required at the dwelling unit separation line of the cornices of two family dwellings and townhouses. All spaces between the chimney and the floors and ceilings the chimney passes through shall be fireblocked (1’’ depth of batt or blanket of mineral wool or glass fiber supported by strips of metal or metal lath). ATTIC AND CRAWL SPACE ACCESS A 22" x 30" minimum access opening required for attic areas which have a clear height of over 30". A 16" x 24" minimum access opening is required for crawl spaces. LIGHT AND VENTILATION Glass area in habitable rooms shall not be less than 8% of floor area served. One-half of this area must be available for unobstructed ventilation with screens included. All bedrooms and basements with a partial or complete finish must have one window for emergency escape meeting the following minimums: Maximum height to clear opening: 44" Minimum clear height: 24" Minimum clear width: 20" Minimum clear opening area: 5.7 sq.ft. Exception: Windows less than 44” above the exterior ground may have a minimum net clear opening of 5.0 sq.ft. The emergency escape window shall be operable from the inside without the use of special knowledge, tool or extra force, beyond that required for ADDITION Rev. 09/01/06 -9BP1008 normal window operation. Compliance with the above must be indicated by one of the following methods: (Simply showing the rough frame opening for windows is specifically not acceptable.) 1. A window schedule showing net window opening, net glass area and window type and keyed to specific location in the normal manner, or 2. Net opening, net glass area and window type may be shown at each location on the plans, or 3. A specific manufacturer and its sizing Code Number may be indicated at each location on the plans. Indicate clear opening height above the floor level and size of all windows on elevation drawings. Attic and enclosed rafter space ventilation (net free) area is to be at least 1/150 of the area served. Two remote vents required for each Attic/space (minimum). Exception: Required ventilation area may be reduced to 1/300 where a vapor retarder having a transmission rate not exceeding 1 perm is provided on the conditioned side of the insulation, or if the gable or ridge vents are located in the upper 1/3 of the attic or enclosed rafter space and provide 50% to 80% of the required vent area with the balance of the required vent area is supplied by eave or cornice vents. A 1’’ clearance between the top of the insulation and the bottom of the roof sheathing is required when ventilation is provided by eave or cornice vents. Foundation crawl spaces are to have a minimum clear height of at least 18" and shall be provided with vent openings located within 3’ of each corner. The total vent area shall be at least 1/150 of the area served. Exceptions: 1. When an approved vapor barrier is provided over the surface of the ground the required vent area may be reduced to 10% of the above and the vents may have operable louvers. 2. Clear height may be reduced when preservative-treated or naturally durable wood is used for the framing and subfloor. Enclosed attic, rafter and crawl space areas may be ventilated by a mechanical exhaust and supply air system of .02 cfm/sq. ft. of horizontal area. The ventilation systems shall operate continuously. Unfinished basements and utility rooms require natural ventilation (net openable area) at the ratio of 1% of the square footage floor area served. Mechanical ventilation with outdoor air (not recirculated air) in accordance with the mechanical code may be substituted at a rate of .05 cfm/sq. ft. of area. SAFETY GLAZING: Glazing installed in the following locations shall be tested and labeled in accordance with CPSC 16 CFR Part 1201 Standard as a Type I or II category (glazing in sliding doors; any glazing exceeding 9 square feet in area required to be safety glazing in accordance with one of the six categories listed below; and all glazing in doors and enclosures for hot tubs, whirlpools, saunas, steam rooms, bathtubs , and showers shall be a Type II category and noted as such on the Architectural plans): ADDITION Rev. 09/01/06 -10BP1008 Indicate size of all windows, bottom edge of window height above the floor, and the horizontal distance from the edge of a window to a door where safety glazing might be required by the following conditions. Glazing in the following locations shall be safety glazing: 1. Glazing in doors and any portion of a building wall or fence enclosing bathtubs, showers, hot tubs, whirlpools, saunas, steam rooms, spas, indoor or outdoor pools which is located 60” or less, measured horizontally, from the water’s edge and less than 60" vertically above a standing surface. 2. Any glazing material adjacent to a door if the nearest vertical edge of the glazing material is within a 24" arc of either vertical edge of the door in a closed position and if the bottom edge of the glazing material is less than 60" above the floor. Exceptions: a. Where there is an intervening wall or barrier to prevent a person from striking the glazing while approaching the door. b. Glazing adjacent to a door serving a closet or storage area 3’ or less in depth c. Decorative glass 3. Safety glazing is required for fixed or operable panels that meet all of the following a.) individual pane greater than 9 sq. ft. and; b.) bottom edge less than 18" above floor and; c.) top edge more than 36" above floor and; d.) walking surface within 36" horizontally Exceptions: i. Decorative glass. ii. 1 ½” protective bar is placed 34’’ to 38’’ above the walking surface. The bar shall be capable of withstanding a 50 pounds per linear foot load without contacting the glass. 4. All doors Exception: Decorative glass 5. Glazing in hand or guard rails 6. Glazing adjacent to stairways, landings, and ramps within 36’’ horizontally of the walking surface and less than 60’’ vertically above the plane of the walking surface. And Glazing adjacent to stairways within 60’’ horizontally of the bottom tread in any direction when the exposed surface of the glass is less than 60’’ above the tread nosing. Exception: The glazing is protected by a guardrail or a handrail, including balusters or in-fill panels complying with the provisions of Sections 1012 and 1607.7 of the 2003 International Building Code and the glazing is located more than 18’’ horizontally from this guard or handrail. ADDITION Rev. 09/01/06 -11BP1008 The following products and uses are specifically exempt from the standard for architectural glazing in hazardous locations: 1. Louvered windows and jalousies 3/16’’or greater in thickness and no longer than 48’’. 2. Openings in doors through which a 3 inch diameter sphere is unable to pass. ENERGY CONSERVATION Typical sections through the building must be provided indicating the type, thickness and "R" value of insulating materials. "U" values of the windows, doors and skylights must be specified. Design requirements by Accepted Practice Method: (R-values indicated must be obtained by the insulation material used, not by the total system). Roof/Ceiling Min. R-30 Frame wall & band joists Min. R-13 Floor over unheated crawl space Min R-19 Basement Foundation Wall Min R-8 Note: Each basement wall that is more than 50% above grade shall be fully insulated (min. R-13) from slab to top of wall. Frame wall construction recommended. Slab-on-grade floors Min. R-6.2(heated)/R-4.2 (unheated) Note: The insulation shall be along the perimeter of the foundation wall downward from the slab a minimum distance of 24" or horizontally under the slab for a minimum of 24". Windows and doors Max. U-.50 Note: Windows and glass doors for the entire house (existing plus addition) shall not exceed 16% of the gross insulated frame wall area. Mechanical Ducts in unheated spaces: Attic: Min R=6.5 Crawl space: Insulated (no R value specified) An energy calculation verifying overall envelope compliance shall be provided if any one of the exterior envelope components listed above is not met or with respect to windows and doors the table in the Single-Family Dwelling Checklist@ for Uf may be used. Forms are available for this analysis. DOORS Locks with thumb turns on the inside are permitted. Inside key operation is permitted provided the key cannot be removed from the lock when locked from the inside. Minimum width of an interior egress door leaf is 28" (2'-4" door leaf). EXTERIOR STAIRS & STAIR/PORCH LANDINGS All doors require a 3’x 3’ landing a maximum of 1.5” below the door threshold. The landing is typically the deck or porch surface. Exceptions: 1. A landing serving the primary means of egress (main entry door) of the house shall be a ADDITION Rev. 09/01/06 -12BP1008 maximum of 7 ¾” below the door threshold as long as the door, other than the exterior storm or screen door, does not swing outward over the landing. 2. A landing serving a door not considered a primary means of egress (i.e. kitchen door leading to a deck) may be placed at the bottom of a stair consisting of two risers or less (8 ¼” maximum per rise) as long as the door, other than the exterior storm or screen door, does not swing outward over the stair. Minimum clear width of stairways is 36". Minimum headroom clear height of stairways is 6'-8" measured vertically Note number and size of stringers (2 x 12's minimum) and material used for treads. Stairs shall be designed for a 40 psf live load or 300 lb. concentrated load on 4 sq. inches at mid span of a tread; whichever produces the greater stress and deflections. Maximum riser height is 8 ¼" and the minimum tread depth (measured horizontally from tread nose to tread nose) is 9". A ¾’’ tread nosing is required on stairways with solid risers. Exception: Nosing is not required where the tread depth is 11’’ Stair winders must have 9" minimum tread depth at a point not more than 12" from the narrow end and be at least 6" in depth at the narrow end. Indicate at least one continuous handrail on stair plan and section at 34’’ to 38" above nosing for stairs with 4 or more risers. Handrails (and other projections below the handrail) shall not project more than 4 1/2" into the required stairway width. Handrails (and other projections below the handrail) shall not project more than 4 1/2" into the required stairway width. Guards along open-sided stairs with a total rise more than 30’’ shall be a minimum of 34’’in height above the leading edge of the tread and minimum of36" in height at the stair landings. Minimum 36" high guards shall be provided along balconies, areaways, mezzanines and open-sided walking surfaces where the difference in floor levels is more than 30’’ Open guards shall have intermediate vertical balusters spaced less than 4" apart. Exception: Openings on the side(s) of a stair shall have balusters spaced less than 4 3/8” apart. DECKS For larger exterior decks obtain St. Louis County "Building Permit Requirements For Sun-Decks" for additional information and details that need to be included on the plans. PRE-FAB FIREPLACES Combustible trim and mantels attached to the fireplace face shall be a minimum of 6" from the opening. Combustible material within 12” of the fireplace opening shall not project more than 1/8” for each 1” distance from the opening. ADDITION Rev 09/01/06 -13BP1008 Hearth sizes: Solid fuel with 6 sq.ft. of opening or more = 1'-8" minimum, and 12" each side. Solid fuel with less than 6 sq.ft. of opening = 1'-4" minimum, and 8" each side. Gas fired - per manufacturer's installation instructions. Chimneys shall extend above the roof that they penetrate a minimum of 3'. Chimney outlets shall be 2' higher than any portion of the building within 10' horizontally. Indicate chimney locations on the exterior elevations. All pre-fab metal fireplaces and stoves indicate manufacturer, make and model number directly on the plan. Provide 1 copy of manufacturer's installation instructions and proof of testing by a nationally recognized testing agency. Gas fireplaces, gas logs, and gas room heaters shall be installed in accordance with Chapter 24. Combustion air shall be provided in accordance with Section G2407. Factory-built or masonry fireplaces shall be equipped with an exterior air supply to assure proper fuel combustion. The air duct serving the exterior air intake and the interior air outlet shall be listed and installed in accordance with the manufacturer’s installation instructions for both the factorybuilt and the masonry fireplace. The cross sectional area of the passageway shall be a minimum of 6 square inches but not more than 55 square inches unless otherwise noted in the installation instructions. The exterior air intake (covered with a corrosion resistant screen of ¼’’ mesh) may draw air from a naturally ventilated crawl space or attic. The interior air outlet may be located in the back or sides of the fireplace chamber or within 24 inches of the firebox opening on or near the floor. The interior air outlet shall be closable and designed to prevent burning material from dropping into a concealed combustible space. Exterior air intakes shall be installed below the level of the base of the firebox when the interior air inlet is installed inside the fireplace chamber. MINIMUM ROOM DIMENSIONS Habitable rooms, hallways, bathrooms, laundry rooms and habitable basements shall have a minimum clear height of 7'-0" and at least 70 sq.ft. of floor area. The minimum allowable room dimensions to be 7'-0". HEATING AND AIR CONDITIONING AND GENERAL MECHANICAL For additions less than 25% of the size of the existing finished area of the house show how the addition will be heated on the floor plan. Indicate duct extensions and diffuser locations (if extending existing system), baseboard units, or other acceptable method of providing heating/cooling. Residential bathrooms without windows for natural ventilation shall exhaust 50 CFM minimum to the exterior. It is not permissible to discharge exhaust to the attic. Exception: Half-baths without a tub or shower may exhaust to the attic. ELECTRICAL Show location of all receptacles, lights, ceiling fans, exhaust fans and switches on the floor plan. Identify all 240 volt receptacles/circuits. Indicate which light and/or receptacles are controlled by switches. ADDITION Rev 09/01/06 -14BP1008 Ground fault circuit-interruption protection shall be provided for all 125 volt, single phase, 15 and 20 ampere receptacles installed in the following locations: 1. Bathrooms 2. Garages except ceiling mounted receptacle for garage door opener and grade-level portions of unfinished accessory buildings.. 3. Outdoors (including inside screened enclosures) 4. Unfinished basement areas and crawl spaces except for laundry circuit and single receptacle dedicated to sump pumps. 5. Receptacles intended to serve kitchen counter top surfaces. 6. Receptacles intended to serve the counter top surfaces of a wet bar that are located within 6'-0" of the outside edge of the wet bar sink. Arc-fault circuit interruption protection shall be provided for all circuits supplying power to bedrooms. Receptacles are required to be installed in the following areas: 1. In all habitable rooms except bathrooms so that no space along a wall is more than 6'-0"from a receptacle. All wall spaces 2'-0" wide or greater require receptacles. Fixed panels of glass doors, fixed room dividers such as free standing bar-type counters or railings shall be included in the 6'-0" measurement. 2. In hallways of 10'-0" or more in length. (Foyer is an entry hallway.) 3. Kitchen and dining area counter top receptacles shall be supplied by at least 2 different 20 amp circuits. Receptacles shall be installed so that no point along the counter is more than 24" from a receptacle. All counter top areas 12" wide or greater separated by sinks, ranges or refrigerators shall be provided with receptacles. Receptacles installed face-up in counter work-surface are prohibited. At least one receptacle shall be installed to serve each island or peninsula counter space that is 24" x 12" or greater. 4. In bathrooms at least one wall mounted receptacle installed within 36" of each basin. 5. Outdoor receptacles (weather-proof type) installed at the front and back of the house, accessible to grade level and not more than 6'-6" above grade level. 6. At least 1 receptacle in laundry area supplied by a dedicated 20 ampere branch circuit. 7. At least 1 receptacle in unfinished basement areas and the garage in addition to the laundry receptacle. 8. Required receptacle outlets located in floors shall be within 18" of wall or fixed room divider and shall be installed in boxes listed for the purpose. Lighting is required in the following areas: 1. At least 1 wall switched lighting outlet shall be installed in every habitable room, bathroom, hallway, stairway, attached garage, detached garage (with electrical power) and at exterior doors. Occupancy sensors may be used in addition to a wall switch or be equipped with a manual override and be located at the customary wall switch location. 2. At least 1 lighting outlet and one receptacle are required in each attic, crawl space, basement or utility room that is used for storage or contains heating, air-conditioning or other equipment requiring servicing. The light switch shall be located at the point of entry. Lighting in clothes closets: 1. The use of incandescent fixtures with open or only partially enclosed lamps and the use of pendant fixtures are prohibited. 2. Fixtures may be located only where there are the following minimum clearances to the nearest point of storage space: ADDITION Rev 09/01/06 -15BP1008 - surface mounted incandescent fixtures - 12" minimum. - surface mounted fluorescent fixtures and recessed fixtures - 6" minimum. Electrical panels: 1. Electrical panels shall not be installed in bathrooms or clothes closets. 2. Lighting is required in the vicinity of the electrical panel. 3. Electrical panels in new construction shall not be installed in areas with less than 6'-6" headroom. 4. A minimum clearance of 3’-0” deep and 30” wide is required in front of electrical panels. Counters and cabinets cannot be installed under the electrical panel. Lighting fixtures above bathtubs: No parts of hanging fixtures, track lighting and ceiling paddle fans shall be installed within 3'-0" horizontally of a bathtub, measured from the outside edge of the tub and 8'-0" vertically from the top of the tub rim. PLUMBING When applicable, show location of bar sink, lavatories, water closets, bathtubs, showers, hose bibs and other plumbing fixtures on the plans. Show location of plumbing chases. Show location of washer hose connection bibs and laundry standpipe for washer/dryer area. Gutters and downspouts required on roof overhangs less than 36" Note: The preceding requirements apply to most simple residential room additions. However, the Plan Reviewer may determine that unusual circumstances dictate the need for additional information on any particular project. ADDITION Rev 09/01/06 -16- BP1008 ROOM ADDITION BRACING GUIDELINE FOR ONE AND TWO FAMILY DWELLINGS OR TOWNHOUSES The plans for a room addition do not have to identify the brace wall line locations and identify the percentage of braced wall panels with respect to a braced wall line if all of the following criteria are met: 1. The building addition exterior walls are sheathed with 7/16” or thicker wood structural panels (plywood or OSB). The wood structural panels shall be applied to all new exterior walls, gable ends, and band boards. All vertical joints between panels shall be blocked. Horizontal joints between panels on detached dwellings may remain unblocked. 2. Braced wall panels are located in every exterior braced wall line in accordance with the following criteria: The edge of the first braced wall panel meeting the width established in the table below is located 12’-6” or less from each end of the braced wall line. Exception: The edge of the first braced wall panel may be located more than 12’-6” and up to 20’-0” from the end of the braced wall line if the collector system “Panel Offset” criteria on p.9 of Appendix A, One and Two Family Wind Bracing Guidelines is adhered to and detailed on the construction documents or when an Engineer or Architect provides calculations and details for an alternate collector system. b. The centerline spacing of braced wall panels in a braced wall line may not exceed 25’. 3. Braced wall panel locations are shown on the floor plans or the elevation views and meet the widths established in the following table: WIDTH OF SOLID PANEL a, b 9’ wall height 10’ wall height 36” 40” d 18” 20” d a. Plywood/OSB Panel APA Narrow Portal Wallc a b 3:1 6:1 8’ wall height 32” 16”d 12’ wall height 48” 24” d Linear interpolation is permitted Wall height is the vertical distance from the bottom of the sole/sill plate to the top of the double top plate. An additional 2” variation in height is allowed for pre cut stud framing. c The APA Narrow-Wall Panel, if applicable, shall be constructed in accordance with Figure 3. The designer shall provide this detail on the construction documents. d This APA Narrow Portal Wall width assumes the beam is placed under the top plate of the wall. One may compute the required width based on a 6:1 height to width ratio for a top of beam height located lower in the wall (i.e.: 20” Portal Wall can be used when the top of beam is at 10’-0” in a 12’-0” tall wall). 4. The exterior wall corners shall be constructed in accordance with Figures 1 and 2. The designer shall provide these details on the construction documents. 5. When the perpendicular distance between the exterior braced wall lines exceeds 50’, a Design Professional (Engineer or Architect registered in the State of Missouri) shall include the following certification on the drawings: The interior and exterior wall configuration braces the structure in accordance with or equivalent to the lateral bracing provisions of Section R602.10 of the 2003 edition of the IRC or Section 2305 of the 2003 edition of the IBC. 6. Wall height may not exceed 12’ (12’-2” actual). Walls greater than 12’ shall be designed and detailed by the Design Professional to resist wind loads in both the longitudinal and transverse directions. ADDITION Rev 09/01/06 -17- BP1008 Figure 1 Figure 2 * * *End stud on the above details may be shifted 7/16” to allow stud face to be aligned with sheathing. ADDITION Rev 09/01/06 -18- BP1008 ROOM ADDITION BRACING GUIDELINES (continued) Figure 3 Outside elevation CONSTRUCTION DETAILS FOR THE APA NARROW-WALL BRACING METHOD WITHOUT HOLD-DOWNS Side Elevation Extent of header [Two braced wall segments] Extent of header [One braced wall segment] Sheathing filler if needed 16d sinker nails in 2 rows @ 3” o.c. 1000 lbs header-tojack-stud strap on both sides of opening Max. height 12’* 2’ to 18’ (finished width) Fasten sheathing to header with Top plate continuity is 8d common nails in 3” grid pattern required per R602.3.2 as shown and 3” o.c. in all framing (studs and sills) typ . 1000 lb header-to-jack-stud strap on both sides of opening (Install on backside as shown on Side Elevation) Braced wall segment If panel splice is needed it shall per R602.10.5 occur within 24” of mid-height. Blocking is not required. No. of jack studs Min. width based on 6:1 height-to-width per table R502.5 ratio. For example: 16” min. for 8’ height [1&2] Min. 2”x2”x3/16” plate Min. (2) 2x4 typ. 3/8” min. thickness wood structural panel sheathing Anchor bolt per R403.1.6 typ. Over concrete or masonry block foundation Framing Anchors 670 lb 670 lb Nail sole plate to joist per table R602.3(1) Nail sole plate to joist per table R602.3(1) Wood Structural Panel Sheathing over Approved Band Joist Approved Band Joist Over raised wood floor or second floor – framing anchor option Min. Overlap 8d common nails 3” o.c. top and bottom Nail sole plate to joist per table R602.3(1) Nail sole plate to joist per table R602.3(1) Wood Structural Panel Sheathing over Approved Band Joist Approved Band Joist *Cripple wall framing consisting of stud framing, single bottom plate, and double top plate may be added to the top of the APA Narrow Portal Wall as long as the combined height of the two walls is less than or equal to 12’ and the two walls are strapped together on the interior side with a vertical 16 gauge metal 1 ½” in wide by 21” long strap. A minimum of 10” of the strap shall be connected to each wall or gable truss with 9-16d nails for a total of 18-16d nails in the entire strap. Straps shall be located at each end of the connected walls or wall and gable truss where space allows for the 10” length of strap. The spacing between the straps may not exceed 4’ on center. The straps shall not be bent horizontally to accommodate wood framing. If applicable, nailers should be added to one of the walls or gable end using a minimum of 9-16d nails to create the vertical plane needed to mount the strap. ADDITION Rev 09/01/06 -19BP1008 Over raised wood floor or second floor – Wood structural panel overlap option ADDITION Rev 09/01/06 -20- BP1008 ADDITION Rev 09/01/06 -21- BP1008 ADDITION Rev 09/01/06 -22- BP1008 ADDITION Rev 09/01/06 -23- BP1008 ADDITION Rev 09/01/06 -24- BP1008