The provisions of this chapter shall establish the minimum requirements for exterior walls; exterior wall coverings; exterior wall openings; exterior windows and doors; and architectural trim.
Exterior walls shall provide the building with a weather-resistant exterior wall envelope. The exterior wall envelope shall include flashing, as described in Section 1404.4. The exterior wall envelope shall be designed and constructed in such a manner as to prevent the accumulation of water within the wall assembly by providing a water-resistive barrier behind the exterior veneer, as described in Section 1403.2, and a means for draining water that enters the assembly to the exterior. Protection against condensation in the exterior wall assembly shall be provided in accordance with Section 1404.3.
Exceptions:
- A weather-resistant exterior wall envelope shall not be required over concrete or masonry walls designed in accordance with Chapters 19 and 21, respectively.
Compliance with the requirements for a means of drainage, and the requirements of Sections 1403.2 and 1404.4, shall not be required for an exterior wall envelope that has been demonstrated through testing to resist wind-driven rain, including joints, penetrations and intersections with dissimilar materials, in accordance with ASTM E331 under the following conditions:
- 2.1. Exterior wall envelope test assemblies shall include not fewer than one opening, one control joint, one wall/eave interface and one wall sill. Tested openings and penetrations shall be representative of the intended end-use configuration.
- 2.2. Exterior wall envelope test assemblies shall be not less than 4 feet by 8 feet (1219 mm by 2438 mm) in size.
- 2.3. Exterior wall envelope assemblies shall be tested at a minimum differential pressure of 6.24 pounds per square foot (psf) (0.297 kN/m2).
- 2.4. Exterior wall envelope assemblies shall be subjected to a minimum test exposure duration of 2 hours.
The exterior wall envelope design shall be considered to resist wind-driven rain where the results of testing indicate that water did not penetrate control joints in the exterior wall envelope, joints at the perimeter of openings or intersections of terminations with dissimilar materials.
- Exterior insulation and finish systems (EIFS) complying with Section 1407.4.1.
Exterior walls on buildings of Type I, II, III or IV construction that are greater than 40 feet (12 192 mm) in height above grade plane and contain a combustible water-resistive barrier shall be tested in accordance with and comply with the acceptance criteria of NFPA 285. For the purposes of this section, fenestration products, flashing of fenestration products and water-resistive-barrier flashing and accessories at other locations, including through wall flashings, shall not be considered part of the water-resistive barrier.
Exceptions:
- Walls in which the water-resistive barrier is the only combustible component and the exterior wall has a wall covering of brick, concrete, stone, terra cotta, stucco or steel with minimum thicknesses in accordance with Table 1404.2.
- Walls in which the water-resistive barrier is the only combustible component and the water-resistive barrier has a peak heat release rate of less than 150 kW/m2, a total heat release of less than 20 MJ/m2 and an effective heat of combustion of less than 18 MJ/kg as determined in accordance with ASTM E1354 and has a flame spread index of 25 or less and a smoke-developed index of 450 or less as determined in accordance with ASTM E84 or UL 723. The ASTM E1354 test shall be conducted on specimens at the thickness intended for use, in the horizontal orientation and at an incident radiant heat flux of 50 kW/m2.
Exterior walls shall provide weather protection for the building. The materials of the minimum nominal thickness specified in Table 1404.2 shall be acceptable as approved weather coverings.
COVERING TYPE | MINIMUM THICKNESS
(inches)
|
Adhered masonry veneer | |
Architectural cast stone | 0.75 |
Other | 0.25 |
Aluminum siding | 0.019 |
Anchored masonry veneer | |
Stone (natural) | 2.0 |
Architectural cast stone | 1.25 |
Other | 2.0 |
Asbestos-cement boards | 0.125 |
Asbestos shingles | 0.156 |
Cold-rolled copperd | 0.0216 nominal |
Copper shinglesd | 0.0162 nominal |
Exterior plywood (with sheathing) | 0.313 |
Exterior plywood (without sheathing) | See Section 2304.6 |
Fiber cement lap siding | 0.25c |
Fiber cement panel siding | 0.25c |
Fiberboard siding | 0.5 |
Glass-fiber reinforced concrete panels | 0.375 |
Hardboard sidingc | 0.25 |
High-yield copperd | 0.0162 nominal |
Lead-coated copperd | 0.0216 nominal |
Lead-coated high-yield copper | 0.0162 nominal |
Marble slabs | 1 |
Particleboard (with sheathing) | See Section 2304.6 |
Particleboard (without sheathing) | See Section 2304.6 |
Porcelain tile | 0.25 |
Steel (approved corrosion resistant) | 0.0149 |
Structural glass | 0.344 |
Stucco or exterior cement plaster | |
Three-coat work over: | |
Metal plaster base | 0.875b |
Unit masonry | 0.625b |
Cast-in-place or precast concrete | 0.625b |
Two-coat work over: | |
Unit masonry | 0.5b |
Cast-in-place or precast concrete | 0.375b |
Terra cotta (anchored) | 1 |
Terra cotta (adhered) | 0.25 |
Vinyl siding | 0.035 |
Wood shingles | 0.375 |
Wood siding (without sheathing)a | 0.5 |
For SI: 1 inch = 25.4 mm, 1 ounce = 28.35 g, 1 square foot = 0.093 m2.
- Wood siding of thicknesses less than 0.5 inch shall be placed over sheathing that conforms to Section 2304.6.
- Exclusive of texture.
- As measured at the bottom of decorative grooves.
- 16 ounces per square foot for cold-rolled copper and lead-coated copper, 12 ounces per square foot for copper shingles, high-yield copper and lead-coated high-yield copper.
- Basement walls.
- Below-grade portion of any wall.
- Construction where moisture or its freezing will not damage the materials.
- Conditions where Class III vapor retarders are required in Section 1404.3.2.
Class III vapor retarders shall be permitted where any one of the conditions in Table 1404.3.2 is met. Only Class III vapor retarders shall be used on the interior side of frame walls where foam plastic insulating sheathing with a perm rating of less than 1 is applied in accordance with Table 1404.3.2 on the exterior side of the frame wall.
CLASS III VAPOR RETARDERS
ZONE | CLASS III VAPOR RETARDERS PERMITTED FOR:a |
Marine 4 | Vented cladding over wood structural panels Vented cladding over fiberboard Vented cladding over gypsum Continuous insulation with R-value ≥ R2.5 over 2 × 4 wall Continuous insulation with R-value ≥ R3.75 over 2 × 6 wall |
5 | Vented cladding over wood structural panels Vented cladding over fiberboard Vented cladding over gypsum Continuous insulation with R-value ≥ R5 over 2 × 4 wall Continuous insulation with R-value ≥ R7.5 over 2 × 6 wall |
6 | Vented cladding over fiberboard Vented cladding over gypsum Continuous insulation with R-value ≥ R7.5 over 2 × 4 wall Continuous insulation with R-value ≥ R11.25 over 2 × 6 wall |
7 and 8 | Continuous insulation with R-value ≥ R10 over 2 × 4 wall Continuous insulation with R-value ≥ R15 over 2 × 6 wall |
For SI: 1 pound per cubic foot = 16 kg/m3.
- Spray foam with a maximum permanence of 1.5 perms at the installed thickness applied to the interior cavity side of wood structural panels, fiberboard, insulating sheathing or gypsum is deemed to meet the continuous insulation requirement where the spray foam R-value meets or exceeds the specified insulating sheathing R-value.
The vapor retarder class shall be based on the manufacturer's certified testing or a tested assembly.
The following shall be deemed to meet the class specified:
Class I: | Sheet polyethylene, nonperforated aluminum foil with a perm rating of less than or equal to 0.1. |
Class II: | Kraft-faced fiberglass batts or paint with a perm rating greater than 0.1 and less than or equal to 1.0. |
Class III: | Latex or enamel paint with a perm rating of greater than 1.0 and less than or equal to 10.0. |
For the purposes of this section, vented cladding shall include the following minimum clear airspaces:
Wood veneers on exterior walls of buildings of Type I, II, III and IV construction shall be not less than 1 inch (25 mm) nominal thickness, 0.438-inch (11.1 mm) exterior hardboard siding or 0.375-inch (9.5 mm) exterior-type wood structural panels or particleboard and shall conform to the following:
- The veneer shall not exceed 40 feet (12 190 mm) in height above grade. Where fire-retardant-treated wood is used, the height shall not exceed 60 feet (18 290 mm) in height above grade.
- The veneer is attached to or furred from a noncombustible backing that is fire-resistance rated as required by other provisions of this code.
- Where open or spaced wood veneers (without concealed spaces) are used, they shall not project more than 24 inches (610 mm) from the building wall.
Anchored stone veneer units not exceeding 10 inches (254 mm) in thickness shall be anchored directly to masonry, concrete or to stud construction by one of the following methods:
- With concrete or masonry backing, anchor ties shall be not less than 0.1055-inch (2.68 mm) corrosion-resistant wire, or approved equal, formed beyond the base of the backing. The legs of the loops shall be not less than 6 inches (152 mm) in length bent at right angles and laid in the mortar joint, and spaced so that the eyes or loops are 12 inches (305 mm) maximum on center in both directions. There shall be provided not less than a 0.1055-inch (2.68 mm) corrosion-resistant wire tie, or approved equal, threaded through the exposed loops for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length bent so that the tie will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.
- With wood stud backing, a 2-inch by 2-inch (51 by 51 mm) 0.0625-inch (1.59 mm) zinc-coated or nonmetallic coated wire mesh with two layers of water-resistive barrier in accordance with Section 1403.2 shall be applied directly to wood studs spaced not more than 16 inches (406 mm) on center. On studs, the mesh shall be attached with 2-inch-long (51 mm) corrosion-resistant steel wire furring nails at 4 inches (102 mm) on center providing a minimum 1.125-inch (29 mm) penetration into each stud and with 8d annular threaded nails at 8 inches (203 mm) on center. into top and bottom plates or with equivalent wire ties. There shall be not less than a 0.1055-inch (2.68 mm) zinc-coated or nonmetallic coated wire, or approved equal, attached to the stud with not smaller than an 8d (0.120 in. diameter) annular threaded nail for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length, so bent that the tie will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer.
- With cold-formed steel stud backing, a 2-inch by 2-inch (51 by 51 mm) 0.0625-inch (1.59 mm) zinc-coated or nonmetallic coated wire mesh with two layers of water-resistive barrier in accordance with Section 1403.2 shall be applied directly to steel studs spaced a not more than 16 inches (406 mm) on center. The mesh shall be attached with corrosion-resistant #8 self-drilling, tapping screws at 4 inches (102 mm) on center, and at 8 inches (203 mm) on center into top and bottom tracks or with equivalent wire ties. Screws shall extend through the steel connection not fewer than three exposed threads. There shall be not less than a 0.1055-inch (2.68 mm) corrosion-resistant wire, or approved equal, attached to the stud with not smaller than a #8 self-drilling, tapping screw extending through the steel framing not fewer than three exposed threads for every 2 square feet (0.2 m2) of stone veneer. This tie shall be a loop having legs not less than 15 inches (381 mm) in length, so bent that the tie will lie in the stone veneer mortar joint. The last 2 inches (51 mm) of each wire leg shall have a right-angle bend. One-inch (25 mm) minimum thickness of cement grout shall be placed between the backing and the stone veneer. The cold-formed steel framing members shall have a minimum bare steel thickness of 0.0428 inches (1.087 mm).
Combustible exterior wall coverings shall comply with this section.
Exception: Plastics complying with Chapter 26.
On buildings of Types I, II, III and IV construction, exterior wall coverings shall be permitted to be constructed of combustible materials, complying with the following limitations:
- Combustible exterior wall coverings shall not exceed 10 percent of an exterior wall surface area where the fire separation distance is 5 feet (1524 mm) or less.
- Combustible exterior wall coverings shall be limited to 40 feet (12 192 mm) in height above grade plane.
- Combustible exterior wall coverings constructed of fire-retardant-treated wood complying with Section 2303.2 for exterior installation shall not be limited in wall surface area where the fire separation distance is 5 feet (1524 mm) or less and shall be permitted up to 60 feet (18 288 mm) in height above grade plane regardless of the fire separation distance.
- Wood veneers shall comply with Section 1404.5.
Where permitted by Section 1405.1.1, combustible exterior wall coverings shall be tested in accordance with NFPA 268.
Exceptions:
- Wood or wood-based products.
- Other combustible materials covered with an exterior weather covering, other than vinyl sidings, included in and complying with the thickness requirements of Table 1404.2.
- Aluminum having a minimum thickness of 0.019 inch (0.48 mm).
FIRE
SEPARATION
DISTANCE (feet) |
TOLERABLE
LEVEL INCIDENT
RADIANT HEAT ENERGY (kW/m2) |
---|---|
5 | 12.5 |
6 | 11.8 |
7 | 11.0 |
8 | 10.3 |
9 | 9.6 |
10 | 8.9 |
11 | 8.3 |
12 | 7.7 |
13 | 7.2 |
14 | 6.7 |
15 | 6.3 |
16 | 5.9 |
17 | 5.5 |
18 | 5.2 |
19 | 4.9 |
20 | 4.6 |
21 | 4.4 |
22 | 4.1 |
23 | 3.9 |
24 | 3.7 |
25 | 3.5 |
— |
For SI: 1 foot = 304.8 mm, 1 Btu/H2 • °F = 0.0057 kW/m2 • K.
Where the combustible exterior wall covering is furred out from the exterior wall and forms a solid surface, the distance between the back of the exterior wall covering and the exterior wall shall not exceed 15/8 inches (41 mm). The concealed space thereby created shall be fireblocked in accordance with Section 718.
Exception: The distance between the back of the exterior wall covering and the exterior wall shall be permitted to exceed 15/8 inches (41 mm) where the concealed space is not required to be fireblocked by Section 718.
Where MCM systems are used on exterior walls required to have a fire-resistance rating in accordance with Section 705, evidence shall be submitted to the building official that the required fire-resistance rating is maintained.
Exception: MCM systems not containing foam plastic insulation, which are installed on the outer surface of a fire-resistance-rated exterior wall in a manner such that the attachments do not penetrate through the entire exterior wall assembly, shall not be required to comply with this section.
The thermal barrier specified for MCM in Section 1406.10.2 is not required where:
- The MCM system is specifically approved based on tests conducted in accordance with NFPA 286 and with the acceptance criteria of Section 803.1.1.1, UL 1040 or UL 1715. Such testing shall be performed with the MCM in the maximum thickness intended for use. The MCM system shall include seams, joints and other typical details used in the installation and shall be tested in the manner intended for use.
- The MCM is used as elements of balconies and similar projections, architectural trim or embellishments.
MCM shall not be installed more than 75 feet (22 860 mm) in height above grade plane where installed in accordance with Sections 1406.11.3.1 through 1406.11.3.5.
Exception: Buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 shall be exempt from the height limitation.
- MCM shall have a self-ignition temperature of 650°F (343°C) or greater when tested in accordance with ASTM D1929.
- MCM shall conform to one of the following combustibility classifications when tested in accordance with ASTM D635:
Class CC2: Materials that have a burning rate of 21/2 inches per minute (1.06 mm/s) or less when tested at a nominal thickness of 0.060 inch (1.5 mm) or in the thickness intended for use.
The maximum area of a single MCM panel and the minimum vertical and horizontal separation requirements for MCM panels shall be as provided for in Table 1406.11.3.4. The maximum percentage of exterior wall area of any story covered with MCM panels shall not exceed that indicated in Table 1406.11.3.4 or the percentage of unprotected openings permitted by Section 705.8, whichever is smaller.
Exception: In buildings provided with flame barriers complying with Section 705.8.5 and extending 30 inches (760 mm) beyond the exterior wall in the plane of the floor, a vertical separation shall not be required at the floor other than that provided by the vertical thickness of the flame barrier.
AREA LIMITATION AND SEPARATION REQUIREMENTS FOR MCM PANELS
FIRE SEPARATION DISTANCE (feet) | COMBUSTIBILITY CLASS OF MCM | MAXIMUM PERCENTAGE AREA OF EXTERIOR WALL COVERED WITH MCM PANELS | MAXIMUM SINGLE AREA OF MCM PANELS (square feet) | MINIMUM SEPARATION OF MCM PANELS (feet) | |
Vertical | Horizontal | ||||
Less than 6 | — | Not Permitted | Not Permitted | — | — |
6 or more but less than 11 | CC1 | 10 | 50 | 8 | 4 |
CC2 | Not Permitted | Not Permitted | — | — | |
11 or more but less than or equal to 30 | CC1 | 25 | 90 | 6 | 4 |
CC2 | 15 | 70 | 8 | 4 | |
More than 30 | CC1 | 50 | Not Limited | 3a | 0 |
CC2 | 50 | 100 | 6a | 3 |
For SI: 1 foot = 304.8 mm, 1 square foot = 0.0929 m2.
- For reductions in the minimum vertical separation, see Section 1406.11.3.4.
MCM shall not be installed more than 75 feet (22 860 mm) in height above grade plane where installed in accordance with Sections 1406.11.4.1 through 1406.11.4.4.
Exception: Buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 shall be exempt from the height limitation.
MCM shall not be installed on any wall with a fire separation distance less than 30 feet (9 144 mm).
Exception: Where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the fire separation distance shall be permitted to be reduced to not less than 20 feet (6096 mm).
MCM shall be required to comply with all of the following:
- MCM shall have a self-ignition temperature of 650°F (343°C) or greater when tested in accordance with ASTM D1929.
MCM shall conform to one of the following combustibility classifications when tested in accordance with ASTM D635:
- Class CC1: Materials that have a burning extent of 1 inch (25 mm) or less when tested at a nominal thickness of 0.060 inch (1.5 mm), or in the thickness intended for use.
- Class CC2: Materials that have a burning rate of 21/2 inches per minute (1.06 mm/s) or less when tested at a nominal thickness of 0.060 inch (1.5 mm), or in the thickness intended for use.
The aggregate area of MCM panels shall not exceed 25 percent of the area of any exterior wall face of the story on which those panels are installed. The area of a single MCM panel installed above the first story above grade plane shall not exceed 16 square feet (1.5 m2) and the vertical dimension of a single MCM panel shall not exceed 4 feet (1219 mm).
Exception: Where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the maximum aggregate area of MCM panels shall be increased to 50 percent of the exterior wall face of the story on which those panels are installed and there shall not be a limit on the maximum dimension or area of a single MCM panel.
Flame barriers complying with Section 705.8 and extending 30 inches (762 mm) beyond the exterior wall or a vertical separation of not less than 4 feet (1219 mm) in height shall be provided to separate MCM panels located on the exterior walls at one-story intervals.
Exception: Buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
Where HPL systems are used on exterior walls required to have a fire-resistance rating in accordance with Section 705, evidence shall be submitted to the building official that the required fire-resistance rating is maintained.
Exception: HPL systems not containing foam plastic insulation, which are installed on the outer surface of a fire-resistance-rated exterior wall in a manner such that the attachments do not penetrate through the entire exterior wall assembly, shall not be required to comply with this section.
The thermal barrier specified for HPL in Section 1408.10.2 is not required where:
- The HPL system is specifically approved based on tests conducted in accordance with UL 1040 or UL 1715. Such testing shall be performed with the HPL in the minimum and maximum thicknesses intended for use. The HPL system shall include seams, joints and other typical details used in the installation and shall be tested in the manner intended for use.
- The HPL is used as elements of balconies and similar projections, architectural trim or embellishments.