- AF&PA Wood Frame Construction Manual (WFCM).
- AISI Standard for Cold-Formed Steel Framing—Prescriptive Method for One- and Two-Family Dwellings (AISI S230).
- ICC Standard on the Design and Construction of Log Structures (ICC 400).
CLIMATIC AND GEOGRAPHIC DESIGN CRITERIA
|SUBJECT TO DAMAGE FROM||WINTER |
|ZONE||EFFECTIVE WIND |
|BASIC WIND SPEED (mph-3-second gust)|
> 0 to 10 degrees
>10 to 30 degrees
> 30 to 45 degrees
|MEAN ROOF HEIGHT||EXPOSURE|
ISOLINES OF THE 971/2 PERCENT WINTER (DECEMBER, JANUARY AND FEBRUARY) DESIGN TEMPERATURES (°F)
REGIONS WHERE WIND DESIGN IS REQUIRED
GROUND SNOW LOADS, Pg, FOR THE UNITED STATES (lb/ft2)
GROUND SNOW LOADS, Pg, FOR THE UNITED STATES (lb/ft2)
TERMITE INFESTATION PROBABILITY MAP
- For concrete construction, the wind provisions of this code shall apply in accordance with the limitations of Sections R404 and R611.
- For structural insulated panels, the wind provisions of this code shall apply in accordance with the limitations of Section R613.
In regions where wind design is required in accordance with Figure R301.2(4)B or where the basic wind speed shown on Figure R301.2(4)A equals or exceeds 110 miles per hour (49 m/s), the design of buildings for wind loads shall be in accordance with one or more of the following methods:
- AF&PA Wood Frame Construction Manual (WFCM); or
- ICC Standard for Residential Construction in High-Wind Regions (ICC 600); or
- ASCE Minimum Design Loads for Buildings and Other Structures (ASCE 7); or
- AISI Standard for Cold-Formed Steel Framing—Prescriptive Method For One- and Two-Family Dwellings (AISI S230); or
- International Building Code.
The elements of design not addressed by the methods in Items 1 through 5 shall be in accordance with the provisions of this code. When ASCE 7 or the International Building Code is used for the design of the building, the wind speed map and exposure category requirements as specified in ASCE 7 and the International Building Code shall be used.
Exception: Wood structural panels with a minimum thickness of 7/16 inch (11 mm) and a maximum span of 8 feet (2438 mm) shall be permitted for opening protection in one- and two-story buildings. Panels shall be precut and attached to the framing surrounding the opening containing the product with the glazed opening. Panels shall be predrilled as required for the anchorage method and shall be secured with the attachment hardware provided. Attachments shall be designed to resist the component and cladding loads determined in accordance with either Table R301.2(2) or ASCE 7, with the permanent corrosion-resistant attachment hardware provided and anchors permanently installed on the building. Attachment in accordance with Table R301.2.1.2 is permitted for buildings with a mean roof height of 33 feet (10 058 mm) or less where located in Wind Zones 1 and 2 in accordance with Figure R301.2(4)C.
|FASTENER TYPE||FASTENER SPACING (inches)a, b|
|4 feet <|
≤ 6 feet
|6 feet <|
≤ 8 feet
|No. 8 wood screw based|
anchor with 2-inch embedment
|No. 10 wood screw based |
anchor with 2-inch embedment
|1/4-inch lag screw based anchor|
with 2-inch embedment length
- This table is based on 130 mph wind speeds and a 33-foot mean roof height.
- Fasteners shall be installed at opposing ends of the wood structural panel. Fasteners shall be located a minimum of 1 inch from the edge of the panel.
- Anchors shall penetrate through the exterior wall covering with an embedment length of 2 inches minimum into the building frame. Fasteners shall be located a minimum of 21/2 inches from the edge of concrete block or concrete.
- Where panels are attached to masonry or masonry/stucco, they shall be attached using vibration-resistant anchors having a minimum ultimate withdrawal capacity of 1500 pounds.
|3-second gust, V3s||85||90||100||105||110||120||125||130||140||145||150||160||170|
|Fastest mile, Vfm||71||76||85||90||95||104||109||114||123||128||133||142||152|
- Exposure A. Large city centers with at least 50 percent of the buildings having a height in excess of 70 feet (21 336 mm). Use of this exposure category shall be limited to those areas for which terrain representative of Exposure A prevails in the upwind direction for a distance of at least 0.5 mile (0.8 km) or 10 times the height of the building or other structure, whichever is greater. Possible channeling effects or increased velocity pressures due to the building or structure being located in the wake of adjacent buildings shall be taken into account.
- Exposure B. Urban and suburban areas, wooded areas, or other terrain with numerous closely spaced obstructions having the size of single-family dwellings or larger. Exposure B shall be assumed unless the site meets the definition of another type exposure.
- Exposure C. Open terrain with scattered obstructions, including surface undulations or other irregularities, having heights generally less than 30 feet (9144 mm) extending more than 1,500 feet (457 m) from the building site in any quadrant. This exposure shall also apply to any building located within Exposure B type terrain where the building is directly adjacent to open areas of Exposure C type terrain in any quadrant for a distance of more than 600 feet (183 m). This category includes flat, open country and grasslands.
- Exposure D. Flat, unobstructed areas exposed to wind flowing over open water for a distance of at least 1 mile (1.61 km). Shorelines in Exposure D include inland waterways, the Great Lakes, and coastal areas of California, Oregon, Washington and Alaska. This exposure shall apply only to those buildings and other structures exposed to the wind coming from over the water. Exposure D extends inland from the shoreline a distance of 1500 feet (457 m) or 10 times the height of the building or structure, whichever is greater.
- The average slope of the top half of the hill, ridge or escarpment is 10 percent or greater.
- The hill, ridge or escarpment is 60 feet (18 288 mm) or greater in height for Exposure B, 30 feet (9144 mm) or greater in height for Exposure C, and 15 feet (4572 mm) or greater in height for Exposure D.
- The hill, ridge or escarpment is isolated or unobstructed by other topographic features of similar height in the upwind direction for a distance measured from its high point of 100 times its height or 2 miles, whichever is less. See Figure R301.2.1.5.1(3) for upwind obstruction.
- The hill, ridge or escarpment protrudes by a factor of two or more above the height of other upwind topographic features located in any quadrant within a radius of 2 miles measured from its high point.
Structures located on the top half of isolated hills, ridges or escarpments meeting the conditions of Section R301.2.1.5 shall be designed for an increased basic wind speed as determined by Table R301.2.1.5.1. On the high side of an escarpment, the increased basic wind speed shall extend horizontally downwind from the edge of the escarpment 1.5 times the horizontal length of the upwind slope (1.5L) or 6 times the height of the escarpment (6H), whichever is greater. See Figure R301.2.1.5.1(2) for where wind speed increase is applied.
BASIC WIND MODIFICATION FOR TOPOGRAPHIC WIND EFFECT
|BASIC WIND SPEED|
|AVERAGE SLOPE OF THE TOP HALF OF HILL, RIDGE OR ESCARPMENT (percent)|
|0.10||0.125||0.15||0.175||0.20||0.23||0.25 or greater|
|Required basic wind speed-up, modified for topographic wind speed up (mph)|
TOPOGRAPHIC FEATURES FOR WIND SPEED-UP EFFECT
ILLUSTRATION OF WHERE ON A TOPOGRAPHIC FEATURE, WIND SPEED INCREASE IS APPLIED
|CALCULATED SDS||SEISMIC DESIGN CATEGORY|
|SDS ≤ 0.17g||A|
|0.17g < SDS ≤ 0.33g||B|
|0.33g < SDS ≤ 0.50g||C|
|0.50g < SDS ≤ 0.67g||D0|
|0.67g < SDS ≤ 0.83g||D1|
|0.83g < SDS ≤1.25g||D2|
|1.25g < SDS||E|
|WALL SUPPORTING||ROOF/CEILING DEAD LOAD|
|15 psf or less||25 psf|
|Roof plus one or two stories||1.0||1.1|
Exception: For wood light-frame construction, floors with cantilevers or setbacks not exceeding four times the nominal depth of the wood floor joists are permitted to support braced wall panels that are out of plane with braced wall panels below provided that:
Exception: Portions of floors that do not support shear walls or braced wall panels above, or roofs, shall be permitted to extend no more than 6 feet (1829 mm) beyond a shear wall or braced wall line.
Exception: For wood light-frame wall construction, one end of a braced wall panel shall be permitted to extend more than 1 foot (305 mm) over an opening not more than 8 feet (2438 mm) wide in the wall below provided that the opening includes a header in accordance with the following:
Exception: For wood-framed wall buildings with bracing in accordance with Tables R602.10.3(1) and R602.10.3(3), the wall stud clear height used to determine the maximum permitted story height may be increased to 12 feet (3658 mm) without requiring an engineered design for the building wind and seismic force-resisting systems provided that the length of bracing required by Table R602.10.3(1) is increased by multiplying by a factor of 1.10 and the length of bracing required by Table R602.10.3(3) is increased by multiplying by a factor of 1.20. Wall studs are still subject to the requirements of this section.
Exception: An additional 8 feet (2438 mm) is permitted for gable end walls.
Individual walls or walls studs shall be permitted to exceed these limits as permitted by Chapter 6 provisions, provided story heights are not exceeded. Floor framing height shall be permitted to exceed these limits provided the story height does not exceed 11 feet 7 inches (3531 mm). An engineered design shall be provided for the wall or wall framing members when they exceed the limits of Chapter 6. Where the story height limits of this section are exceeded, the design of the building, or the noncompliant portions thereof, to resist wind and seismic loads shall be in accordance with the International Building Code.
|Uninhabitable attics without storageb||10|
|Uninhabitable attics with limited storageb, g||20|
|Habitable attics and attics served with fixed stairs||30|
|Balconies (exterior) and deckse||40|
|Guardrails and handrailsd||200h|
|Guardrail in-fill componentsf||50h|
|Passenger vehicle garagesa||50a|
|Rooms other than sleeping room||40|
- Elevated garage floors shall be capable of supporting a 2,000-pound load applied over a 20-square-inch area.
- Uninhabitable attics without storage are those where the maximum clear height between joists and rafters is less than 42 inches, or where there are not two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches high by 24 inches in width, or greater, within the plane of the trusses. This live load need not be assumed to act concurrently with any other live load requirements.
- Individual stair treads shall be designed for the uniformly distributed live load or a 300-pound concentrated load acting over an area of 4 square inches, whichever produces the greater stresses.
- A single concentrated load applied in any direction at any point along the top.
- See Section R502.2.2 for decks attached to exterior walls.
- Guard in-fill components (all those except the handrail), balusters and panel fillers shall be designed to withstand a horizontally applied normal load of 50 pounds on an area equal to 1 square foot. This load need not be assumed to act concurrently with any other live load requirement.
- Uninhabitable attics with limited storage are those where the maximum clear height between joists and rafters is 42 inches or greater, or where there are two or more adjacent trusses with web configurations capable of accommodating an assumed rectangle 42 inches in height by 24 inches in width, or greater, within the plane of the trusses.
- The attic area is accessible from an opening not less than 20 inches in width by 30 inches in length that is located where the clear height in the attic is a minimum of 30 inches.
- The slopes of the joists or truss bottom chords are no greater than 2 inches vertical to 12 units horizontal.
- Required insulation depth is less than the joist or truss bottom chord member depth.
|ROOF SLOPE||TRIBUTARY LOADED AREA IN|
SQUARE FEET FOR ANY
|0 to 200||201 to 600||Over 600|
|Flat or rise less than 4 inches per foot (1:3)||20||16||12|
|Rise 4 inches per foot (1:3) to |
less than 12 inches per foot (1:1)
|Rise 12 inches per foot (1:1) |
ALLOWABLE DEFLECTION OF STRUCTURAL MEMBERSb, c
|STRUCTURAL MEMBER||ALLOWABLE |
|Rafters having slopes greater than 3:12 with no finished ceiling attached to rafters||L/180|
|Interior walls and partitions||H/180|
|Floors/ceilings with plaster or stucco finish||L/360|
|All other structural members||L/240|
|Exterior walls—wind loadsa with plaster or stucco finish||H/360|
|Exterior walls with other brittle finishes||H/240|
|Exterior walls with flexible finishes||H/120d|
|Lintels supporting masonry veneer wallse||L/600|
|EXTERIOR WALL ELEMENT||MINIMUM|
|Walls||Fire-resistance rated||1 hour—tested in accordance with ASTM E 119 or UL 263 with exposure from both sides||< 5 feet|
|Not fire-resistance rated||0 hours||≥ 5 feet|
|Projections||Fire-resistance rated||1 hour on the underside||≥ 2 feet to < 5 feet|
|Not fire-resistance rated||0 hours||≥ 5 feet|
|Openings in walls||Not allowed||N/A||< 3 feet|
|25% maximum of wall area||0 hours||3 feet|
|Unlimited||0 hours||5 feet|
|Penetrations||All||Comply with Section R302.4||< 5 feet|
|None required||5 feet|
|EXTERIOR WALL ELEMENT||MINIMUM|
|Walls||Fire-resistance rated||1 hour—tested in accordance with ASTM E |
119 or UL 263 with exposure from the outside
|Not fire-resistance rated||0 hours||3 feeta|
|Projections||Fire-resistance rated||1 hour on the underside||2 feeta|
|Not fire-resistance rated||0 hours||3 feet|
|Openings in walls||Not allowed||N/A||< 3 feet|
|Unlimited||0 hours||3 feeta|
|Penetrations||All||Comply with Section R302.4||< 3 feet|
|None required||3 feeta|
- Where roof surfaces adjacent to the wall or walls are at the same elevation, the parapet shall extend not less than 30 inches (762 mm) above the roof surfaces.
- Where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is not more than 30 inches (762 mm) above the lower roof, the parapet shall extend not less than 30 inches (762 mm) above the lower roof surface.
Exception: A parapet is not required in the two cases above when the roof is covered with a minimum class C roof covering, and the roof decking or sheathing is of noncombustible materials or approved fire-retardant-treated wood for a distance of 4 feet (1219 mm) on each side of the wall or walls, or one layer of 5/8-inch (15.9 mm) Type X gypsum board is installed directly beneath the roof decking or sheathing, supported by a minimum of nominal 2-inch (51 mm) ledgers attached to the sides of the roof framing members, for a minimum distance of 4 feet (1219 mm) on each side of the wall or walls and there are no openings or penetrations in the roof within 4 feet (1219 mm) of the common walls.
- A parapet is not required where roof surfaces adjacent to the wall or walls are at different elevations and the higher roof is more than 30 inches (762 mm) above the lower roof. The common wall construction from the lower roof to the underside of the higher roof deck shall have not less than a 1-hour fire-resistance rating. The wall shall be rated for exposure from both sides.
- Foundations supporting exterior walls or common walls.
- Structural roof and wall sheathing from each unit may fasten to the common wall framing.
- Nonstructural wall and roof coverings.
- Flashing at termination of roof covering over common wall.
- Townhouses separated by a common 1-hour fire-resistance-rated wall as provided in Section R302.2.
- A fire-resistance rating of 1/2 hour shall be permitted in buildings equipped throughout with an automatic sprinkler system installed in accordance with NFPA 13.
- Wall assemblies need not extend through attic spaces when the ceiling is protected by not less than 5/8-inch (15.9 mm) Type X gypsum board and an attic draft stop constructed as specified in Section R302.12.1 is provided above and along the wall assembly separating the dwellings. The structural framing supporting the ceiling shall also be protected by not less than 1/2-inch (12.7 mm) gypsum board or equivalent.
Exception: Where the penetrating items are steel, ferrous or copper pipes, tubes or conduits, the annular space shall be protected as follows:
|From the residence and attics||Not less than 1/2-inch gypsum board or equivalent applied to the garage side|
|From all habitable rooms above the garage||Not less than 5/8-inch Type X gypsum board or equivalent|
|Structure(s) supporting floor/ceiling assemblies used for separation required by this section||Not less than 1/2-inch gypsum board or equivalent|
|Garages located less than 3 feet from a dwelling unit on the same lot||Not less than 1/2-inch gypsum board or equivalent applied to the interior side of exterior walls that are within this area|
Exception: Flame spread index requirements for finishes shall not apply to trim defined as picture molds, chair rails, baseboards and handrails; to doors and windows or their frames; or to materials that are less than 1/28 inch (0.91 mm) in thickness cemented to the surface of walls or ceilings if these materials exhibit flame spread index values no greater than those of paper of this thickness cemented to a noncombustible backing.
The interior finish shall comply with the following:
- During the 40 kW exposure, flames shall not spread to the ceiling.
- The flame shall not spread to the outer extremity of the sample on any wall or ceiling.
- Flashover, as defined in NFPA 286, shall not occur.
- The peak heat release rate throughout the test shall not exceed 800 kW.
- The total smoke released throughout the test shall not exceed 1,000 m2.
- When such materials are installed in concealed spaces, the flame spread index and smoke-developed index limitations do not apply to the facings, provided that the facing is installed in substantial contact with the unexposed surface of the ceiling, floor or wall finish.
- Cellulose loose-fill insulation, which is not spray applied, complying with the requirements of Section R302.10.3, shall only be required to meet the smoke-developed index of not more than 450.
- Foam plastic insulation shall comply with Section R316.
Exception: Cellulose loose-fill insulation shall not be required to be tested in accordance with CAN/ULC S102.2, provided such insulation complies with the requirements of Section R302.10.1 and Section R302.10.3.
Fireblocking shall be provided in wood-frame construction in the following locations:
- Two-inch (51 mm) nominal lumber.
- Two thicknesses of 1-inch (25.4 mm) nominal lumber with broken lap joints.
- One thickness of 23/32-inch (18.3 mm) wood structural panels with joints backed by 23/32-inch (18.3 mm) wood structural panels.
- One thickness of 3/4-inch (19.1 mm) particleboard with joints backed by 3/4-inch (19.1 mm) particleboard.
- One-half-inch (12.7 mm) gypsum board.
- One-quarter-inch (6.4 mm) cement-based millboard.
- Batts or blankets of mineral wool or glass fiber or other approved materials installed in such a manner as to be securely retained in place.
- Cellulose insulation installed as tested for the specific application.
- Ceiling is suspended under the floor framing.
- Floor framing is constructed of truss-type open-web or perforated members.
- The glazed areas need not be openable where the opening is not required by Section R310 and a whole-house mechanical ventilation system is installed in accordance with Section M1507.
- The glazed areas need not be installed in rooms where Exception 1 above is satisfied and artificial light is provided capable of producing an average illumination of 6 footcandles (65 lux) over the area of the room at a height of 30 inches (762 mm) above the floor level.
- Use of sunroom and patio covers, as defined in Section R202, shall be permitted for natural ventilation if in excess of 40 percent of the exterior sunroom walls are open, or are enclosed only by insect screening.
Exception: Lights that are continuously illuminated or automatically controlled.
- Required glazed openings may face into a roofed porch where the porch abuts a street, yard or court and the longer side of the porch is at least 65 percent unobstructed and the ceiling height is not less than 7 feet (2134 mm).
- Eave projections shall not be considered as obstructing the clear open space of a yard or court.
- Required glazed openings may face into the area under a deck, balcony, bay or floor cantilever provided a clear vertical space at least 36 inches (914 mm) in height is provided.
- For rooms with sloped ceilings, at least 50 percent of the required floor area of the room must have a ceiling height of at least 7 feet (2134 mm) and no portion of the required floor area may have a ceiling height of less than 5 feet (1524 mm).
- Bathrooms shall have a minimum ceiling height of 6 feet 8 inches (2032 mm) at the center of the front clearance area for fixtures as shown in Figure R307.1. The ceiling height above fixtures shall be such that the fixture is capable of being used for its intended purpose. A shower or tub equipped with a showerhead shall have a minimum ceiling height of 6 feet 8 inches (2032 mm) above a minimum area 30 inches (762 mm) by 30 inches (762 mm) at the showerhead.
Exception: Beams, girders, ducts or other obstructions may project to within 6 feet 4 inches (1931 mm) of the finished floor.
- For other than tempered glass, manufacturer's designations are not required provided the building official approves the use of a certificate, affidavit or other evidence confirming compliance with this code.
- Tempered spandrel glass is permitted to be identified by the manufacturer with a removable paper designation
Exception: Glazing not in doors or enclosures for hot tubs, whirlpools, saunas, steam rooms, bathtubs and showers shall be permitted to be tested in accordance with ANSI Z97.1. Glazing shall comply with the test criteria for Class A unless indicated in Table R308.3.1(2).
MINIMUM CATEGORY CLASSIFICATION OF GLAZING USING CPSC 16 CFR 1201
|EXPOSED SURFACE |
AREA OF ONE SIDE
OF ONE LITE
|GLAZING IN STORM OR COMBINATION DOORS|
|GLAZED PANELS REGULATED BY SECTION R308.4.3 |
|GLAZED PANELS REGULATED BY SECTION R308.4.2 |
|GLAZING IN DOORS AND ENCLOSURES REGULATED BY |
|SLIDING GLASS DOORS PATIO TYPE|
|9 square feet or less||I||I||NR||I||II||II|
|More than 9 square feet||II||II||II||II||II||II|
MINIMUM CATEGORY CLASSIFICATION OF GLAZING USING ANSI Z97.1
|EXPOSED SURFACE AREA |
OF ONE SIDE OF ONE LITE
|GLAZED PANELS REGULATED BY |
|GLAZED PANELS REGULATED BY SECTION R308.4.2 |
|DOORS AND ENCLOSURES REGULATED BY |
|9 square feet or less||No requirement||B||A|
|More than 9 square feet||A||A||A|
- Decorative glazing.
- When there is an intervening wall or other permanent barrier between the door and the glazing.
- Glazing in walls on the latch side of and perpendicular to the plane of the door in a closed position.
- Where access through the door is to a closet or storage area 3 feet (914 mm) or less in depth. Glazing in this application shall comply with section R308.4.3.
- Glazing that is adjacent to the fixed panel of patio doors.
- The exposed area of an individual pane is larger than 9 square feet (0.836 m2);
- The bottom edge of the glazing is less than 18 inches (457 mm) above the floor;
- The top edge of the glazing is more than 36 inches (914 mm) above the floor; and
- One or more walking surfaces are within 36 inches (914 mm), measured horizontally and in a straight line, of the glazing.
- Decorative glazing.
- When a horizontal rail is installed on the accessible side(s) of the glazing 34 to 38 inches (864 to 965 mm) above the walking surface. The rail shall be capable of withstanding a horizontal load of 50 pounds per linear foot (730 N/m) without contacting the glass and be a minimum of 11/2 inches (38 mm) in cross sectional height.
- Outboard panes in insulating glass units and other multiple glazed panels when the bottom edge of the glass is 25 feet (7620 mm) or more above grade, a roof, walking surfaces or other horizontal [within 45 degrees (0.79 rad) of horizontal] surface adjacent to the glass exterior.
Exception: Glazing that is more than 60 inches (1524 mm), measured horizontally and in a straight line, from the water's edge of a bathtub, hot tub, spa, whirlpool, or swimming pool.
- When a rail is installed on the accessible side(s) of the glazing 34 to 38 inches (864 to 965 mm) above the walking surface. The rail shall be capable of withstanding a horizontal load of 50 pounds per linear foot (730 N/m) without contacting the glass and be a minimum of 11/2 inches (38 mm) in cross sectional height.
- Glazing 36 inches (914 mm) or more measured horizontally from the walking surface.
- Laminated glass with a minimum 0.015-inch (0.38 mm) polyvinyl butyral interlayer for glass panes 16 square feet (1.5 m2) or less in area located such that the highest point of the glass is not more than 12 feet (3658 mm) above a walking surface or other accessible area; for higher or larger sizes, the minimum interlayer thickness shall be 0.030 inch (0.76 mm).
- Fully tempered glass.
- Heat-strengthened glass.
- Wired glass.
- Approved rigid plastics.
- Glass area 16 square feet (1.49 m2) or less. Highest point of glass not more than 12 feet (3658 mm) above a walking surface or other accessible area, nominal glass thickness not more than 3/16 inch (4.8 mm), and (for multiple glazing only) the other pane or panes fully tempered, laminated or wired glass.
- Glass area greater than 16 square feet (1.49 m2). Glass sloped 30 degrees (0.52 rad) or less from vertical, and highest point of glass not more than 10 feet (3048 mm) above a walking surface or other accessible area.
- Elevated to or above the design flood elevation as determined in Section R322; or
- Located below the design flood elevation provided they are at or above grade on at least one side, are used solely for parking, building access or storage, meet the requirements of Section R322 and are otherwise constructed in accordance with this code.
Exception: A drainage system for window wells is not required when the foundation is on well-drained soil or sand-gravel mixture soils according to the United Soil Classification System, Group I Soils, as detailed in Table R405.1.
Exception: The landing or floor on the exterior side shall not be more than 73/4 inches (196 mm) below the top of the threshold provided the door does not swing over the landing or floor.
Where exterior landings or floors serving the required egress door are not at grade, they shall be provided with access to grade by means of a ramp in accordance with Section R311.8 or a stairway in accordance with Section R311.7.
Exception: Where the nosings of treads at the side of a flight extend under the edge of a floor opening through which the stair passes, the floor opening shall be allowed to project horizontally into the required headroom a maximum of 43/4 inches (121 mm).
Exception: The opening between adjacent treads is not limited on stairs with a total rise of 30 inches (762 mm) or less.
Exception: A nosing is not required where the tread depth is a minimum of 11 inches (279 mm).
- The use of a volute, turnout or starting easing shall be allowed over the lowest tread.
- When handrail fittings or bendings are used to provide continuous transition between flights, transitions at winder treads, the transition from handrail to guardrail, or used at the start of a flight, the handrail height at the fittings or bendings shall be permitted to exceed the maximum height.
- Handrails shall be permitted to be interrupted by a newel post at the turn.
- The use of a volute, turnout, starting easing or starting newel shall be allowed over the lowest tread.
- Type I. Handrails with a circular cross section shall have an outside diameter of at least 11/4 inches (32 mm) and not greater than 2 inches (51 mm). If the handrail is not circular, it shall have a perimeter dimension of at least 4 inches (102 mm) and not greater than 61/4 inches (160 mm) with a maximum cross section of dimension of 21/4 inches (57 mm). Edges shall have a minimum radius of 0.01 inch (0.25 mm).
- Type II. Handrails with a perimeter greater than 61/4 inches (160 mm) shall have a graspable finger recess area on both sides of the profile. The finger recess shall begin within a distance of 3/4 inch (19 mm) measured vertically from the tallest portion of the profile and achieve a depth of at least 5/16 inch (8 mm) within 7/8 inch (22 mm) below the widest portion of the profile. This required depth shall continue for at least 3/8 inch (10 mm) to a level that is not less than 13/4 inches (45 mm) below the tallest portion of the profile. The minimum width of the handrail above the recess shall be 11/4 inches (32 mm) to a maximum of 23/4 inches (70 mm). Edges shall have a minimum radius of 0.01 inch (0.25 mm).
- Guards on the open sides of stairs shall have a height not less than 34 inches (864 mm) measured vertically from a line connecting the leading edges of the treads.
- Where the top of the guard also serves as a handrail on the open sides of stairs, the top of the guard shall not be less than 34 inches (864 mm) and not more than 38 inches (965 mm) measured vertically from a line connecting the leading edges of the treads.
- Windows whose openings will not allow a 4-inch-diameter (102 mm) sphere to pass through the opening when the opening is in its largest opened position.
- Openings that are provided with window fall prevention devices that comply with ASTM F 2090.
- Windows that are provided with window opening control devices that comply with Section R312.2.2.
- In each sleeping room.
- Outside each separate sleeping area in the immediate vicinity of the bedrooms.
- On each additional story of the dwelling, including basements and habitable attics but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.
- Work involving the exterior surfaces of dwellings, such as the replacement of roofing or siding, or the addition or replacement of windows or doors, or the addition of a porch or deck, are exempt from the requirements of this section.
- Installation, alteration or repairs of plumbing or mechanical systems are exempt from the requirements of this section.
- Smoke alarms shall be permitted to be battery operated when installed in buildings without commercial power.
- Hard wiring of smoke alarms in existing areas shall not be required 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 without the removal of interior finishes.
- The foam plastic insulation is separated from the interior of the building by not less than 2 inches (51 mm) of mineral fiber insulation;
- The foam plastic insulation is installed over existing exterior wall finish in conjunction with re-siding; or
- The foam plastic insulation has been tested in accordance with Section R316.6.
- The minimum density is 20 pounds per cubic foot (320 kg/m3).
- The maximum thickness of the trim is 0.5 inch (12.7 mm) and the maximum width is 8 inches (204 mm).
- The interior trim shall not constitute more than 10 percent of the aggregate wall and ceiling area of any room or space.
- The flame spread index does not exceed 75 when tested per ASTM E 84 or UL 723. The smoke-developed index is not limited.
- The maximum thickness of the foam plastic shall be 31/4 inches (83 mm).
- The density of the foam plastic shall be in the range of 0.5 to 2.0 pounds per cubic foot (8 to 32 kg/m3).
- The foam plastic shall have a flame spread index of 25 or less and an accompanying smoke-developed index of 450 or less when tested in accordance with ASTM E 84 or UL 723.
- Wood joists or the bottom of a wood structural floor when closer than 18 inches (457 mm) or wood girders when closer than 12 inches (305 mm) to the exposed ground in crawl spaces or unexcavated area located within the periphery of the building foundation.
- All wood framing members that rest on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.
- Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.
- The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 1/2 inch (12.7 mm) on tops, sides and ends.
- Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground or less than 2 inches (51 mm) measured vertically from concrete steps, porch slabs, patio slabs, and similar horizontal surfaces exposed to the weather.
- Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier.
- Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.
- Horizontal members such as girders, joists and decking.
- Vertical members such as posts, poles and columns.
- Both horizontal and vertical members.
- Columns exposed to the weather or in basements when supported by concrete piers or metal pedestals projecting 1 inch (25.4 mm) above a concrete floor or 6 inches (152 mm) above exposed earth and the earth is covered by an approved impervious moisture barrier.
- Columns in enclosed crawl spaces or unexcavated areas located within the periphery of the building when supported by a concrete pier or metal pedestal at a height more than 8 inches (203 mm) from exposed earth and the earth is covered by an impervious moisture barrier.
- Identification of the treating plant.
- Type of preservative.
- The minimum preservative retention.
- End use for which the product was treated.
- Standard to which the product was treated.
- Identity of the approved inspection agency.
- The designation "Dry," if applicable.
Exception: Quality marks on lumber less than 1 inch (25.4 mm) nominal thickness, or lumber less than nominal 1 inch by 5 inches (25.4 mm by 127 mm) or 2 inches by 4 inches (51 mm by 102 mm) or lumber 36 inches (914 mm) or less in length shall be applied by stamping the faces of exterior pieces or by end labeling not less than 25 percent of the pieces of a bundled unit.
R317.3 Fasteners and Connectors in Contact With Preservative-Treated and Fire-Retardant-Treated Wood
- One-half-inch-diameter (12.7 mm) or greater steel bolts.
- Fasteners other than nails and timber rivets shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B 695, Class 55 minimum.
- Plain carbon steel fasteners in SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment shall be permitted.
R317.3.3 Fasteners for Fire-Retardant-Treated Wood Used in Exterior Applications or Wet or Damp Locations
- Chemical termiticide treatment, as provided in Section R318.2.
- Termite baiting system installed and maintained according to the label.
- Pressure-preservative-treated wood in accordance with the provisions of Section R317.1.
- Naturally durable termite-resistant wood.
- Physical barriers as provided in Section R318.3 and used in locations as specified in Section R317.1.
- Cold-formed steel framing in accordance with Sections R505.2.1 and R603.2.1.
- Buildings where the structural members of walls, floors, ceilings and roofs are entirely of noncombustible materials or pressure-preservative-treated wood.
- When in addition to the requirements of Section R318.1, an approved method of protecting the foam plastic and structure from subterranean termite damage is used.
- On the interior side of basement walls.
- The base flood elevation at the depth of peak elevation of flooding (including wave height) which has a 1 percent (100-year flood) or greater chance of being equaled or exceeded in any given year; or
- The elevation of the design flood associated with the area designated on a flood hazard map adopted by the community, or otherwise legally designated.
- Obtain and reasonably use data available from a federal, state or other source; or
- Determine the design flood elevation in accordance with accepted hydrologic and hydraulic engineering practices used to define special flood hazard areas. Determinations shall be undertaken by a registered design professional who shall document that the technical methods used reflect currently accepted engineering practice. Studies, analyses and computations shall be submitted in sufficient detail to allow thorough review and approval.
Exception: Locating electrical systems, equipment and components; heating, ventilating, air conditioning; plumbing appliances and plumbing fixtures; duct systems; and other service equipment is permitted below the elevation required in Section R322.2 (flood hazard areas including A Zones) or R322.3 (coastal high-hazard areas including V Zones) provided that they are designed and installed to prevent water from entering or accumulating within the components and to resist hydrostatic and hydrodynamic loads and stresses, including the effects of buoyancy, during the occurrence of flooding to the design flood elevation in accordance with ASCE 24. Electrical wiring systems are permitted to be located below the required elevation provided they conform to the provisions of the electrical part of this code for wet locations.
- All wood, including floor sheathing, shall be pressure-preservative-treated in accordance with AWPA U1 for the species, product, preservative and end use or be the decay-resistant heartwood of redwood, black locust or cedars. Preservatives shall be listed in Section 4 of AWPA U1.
- Materials and installation methods used for flooring and interior and exterior walls and wall coverings shall conform to the provisions of FEMA/FIA-TB-2.
- Buildings and structures in flood hazard areas not designated as Coastal A Zones shall have the lowest floors elevated to or above the design flood elevation.
- Buildings and structures in flood hazard areas designated as Coastal A Zones shall have the lowest floors elevated to or above the base flood elevation plus 1 foot (305 mm), or to the design flood elevation, whichever is higher.
- In areas of shallow flooding (AO Zones), buildings and structures shall have the lowest floor (including basement) elevated at least as high above the highest adjacent grade as the depth number specified in feet on the FIRM, or at least 2 feet (610 mm) if a depth number is not specified.
- Basement floors that are below grade on all sides shall be elevated to or above the design flood elevation.
Exception: Unless designed in accordance with Section R404:
- The unsupported height of 6-inch (152 mm) plain masonry walls shall be no more than 3 feet (914 mm).
- The unsupported height of 8-inch (203 mm) plain masonry walls shall be no more than 4 feet (1219 mm).
- The unsupported height of 8-inch (203 mm) reinforced masonry walls shall be no more than 8 feet (2438 mm).
For the purpose of this exception, unsupported height is the distance from the finished grade of the under-floor space to the top of the wall.
- New buildings and buildings that are determined to be substantially improved pursuant to Section R126.96.36.199, shall be located landward of the reach of mean high tide.
- For any alteration of sand dunes and mangrove stands the building official shall require submission of an engineering analysis which demonstrates that the proposed alteration will not increase the potential for flood damage.