CRC · California Residential Code
What are the material, venting and construction requirements for exterior soffits?
If your soffit is exposed to wind pressures of **30 psf or less**, follow the prescriptive material and fastening rules in **§ R704.2** (vinyl/aluminum span limits, minimum panel thicknesses, and nail spacing). If the design wind pressure is **greater than 30 psf**, use **§ R704.3**, which requires soffit materials and attachments to be capable of resisting the wind loads from Table R301.2.1(1) (effective area 10 ft²) and tightens unsupported‑span limits (e.g., vinyl panels need intermediate supports at **>12 in.**). Vent sizing and screening for enclosed soffit/attic ventilation are covered in **§ R806**, not in § R704.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Exterior soffits are governed by a wind‑based two-track rule: when the design wind pressure is 30 psf or less, follow § R704.2; when it exceeds 30 psf, follow § R704.3. The CRC prescribes allowable soffit materials, minimum panel thicknesses, fastener types and unsupported‑span limits (and requires compliance with manufacturer instructions where materials are not specifically addressed) — see § R704.1, § R704.2 and § R704.3.
The single most important rule: if your calculated design wind pressure is greater than 30 psf, use the higher‑wind soffit requirements in § R704.3; otherwise use § R704.2.
Requirements in detail
Which rule applies: wind threshold
- Determine the design wind pressure using the component and cladding loads in Table R301.2.1(1) with an effective wind area of 10 ft² and adjustments per Table R301.2.1(2); that result decides whether § R704.2 (≤ 30 psf) or § R704.3 (> 30 psf) applies. § R704.1.
Materials, minimum thickness and fasteners (prescriptive items)
- Vinyl and aluminum soffit panels: use corrosion‑resistant fasteners (aluminum, galvanized, stainless or rust‑preventative coated nails or staples or other approved fasteners) and fasten at both ends to a supporting component (nailing strip, fascia or subfascia). Unsupported‑span limits trigger intermediate nailing strips per the figures in the code. § R704.2.1.
- Fiber‑cement panels: minimum 1/4 inch (6.4 mm) and must comply with ASTM C1186 Type A (Grade II) or ISO 8336; panel joints must occur over framing or wood structural panel sheathing. § R704.2.2.
- Hardboard panels: minimum 7/16 inch (11.11 mm); fasten with 2-1/2 in. × 0.113 in. siding nails spaced ≤ 6 in. o.c. at panel edges and 12 in. o.c. at intermediate supports (when ≤30 psf prescriptive). § R704.2.3.
- Wood structural panels: minimum nominal 3/8 inch (9.5 mm); fasteners and spacing per the prescriptive table (edges not less than 6 in. o.c., intermediate 12 in. o.c. for the ≤30 psf prescriptive case). § R704.2.4 and the prescriptive alternative in § R704.3.4 for higher wind pressures.
Unsupported spans and intermediate supports (decision points)
- For design wind pressure ≤ 30 psf: vinyl/aluminum panels require intermediate nailing strips when unsupported span > 16 in. (406 mm). § R704.2.1.
- For design wind pressure > 30 psf: vinyl panels require intermediate nailing strips when unsupported span > 12 in. (305 mm). § R704.3.1.
Wind‑resistance performance for high‑wind areas
- When the design wind pressure exceeds 30 psf, soffit materials (vinyl, fiber‑cement, hardboard, wood structural panels) must be capable of resisting the component/cladding wind loads computed from Table R301.2.1(1) using an effective wind area of 10 ft², adjusted by Table R301.2.1(2). § R704.1 and § R704.3.
Manufacturer’s instructions
- Where a soffit material or assembly is not specifically addressed in the prescriptive subsections, the installation must follow the manufacturer’s installation instructions. § R704.2 and § R704.3.
Venting (what the CRC requires and where to look)
- Section R704 itself does not set attic/soffit vent area rules. Ventilation requirements for enclosed attics, enclosed rafter spaces and enclosed soffit/eave spaces are contained in § R806 (Roof Ventilation): minimum net free ventilating area = 1/150 of the vented space (or 1/300 when the exception conditions apply), opening dimensions and screening requirements (openings must have least dimension 1/16 in. to 1/4 in. or be screened) and a requirement that vents be protected against rain/snow and screened to keep out animals. § R806.1, § R806.2, § R806.3, § R806.4.
- Wildland‑Urban Interface (WUI) areas: ventilation openings (including enclosed eave soffit spaces) must comply with the California WUI code (see § R806.1.1 and the WUI Code reference) for ember/flame‑resistant vents. § R806.1.1 and WUI Code.
Quick reference table (decision‑relevant dimensions/values)
| Requirement / value | Value / threshold | Code Reference |
|---|---|---|
| Wind threshold to choose prescriptive set | 30 psf | § R704.1 |
| Vinyl/aluminum unsupported span (≤ 30 psf) | > 16 in. (406 mm) → intermediate nailing strips | § R704.2.1 |
| Vinyl unsupported span (> 30 psf) | > 12 in. (305 mm) → intermediate nailing strips | § R704.3.1 |
| Fiber‑cement minimum thickness | 1/4 in. (6.4 mm); ASTM C1186 Type A Grade II | § R704.2.2 |
| Hardboard minimum thickness | 7/16 in. (11.11 mm) | § R704.2.3 |
| Hardboard fastener spacing (prescriptive) | Edges ≤ 6 in. o.c.; intermediate 12 in. o.c. | § R704.2.3 |
| Wood structural panel minimum thickness (nominal) | 3/8 in. (9.5 mm) | § R704.2.4 |
| Wood structural panel fastener spacing (prescriptive) | Edges ≥ 6 in. o.c.; intermediate 12 in. o.c. (see prescriptive table) | § R704.2.4 and § R704.3.4 |
| Fastener materials for vinyl/aluminum | Aluminum, galvanized, stainless, or rust‑preventative coated | § R704.2.1 |
| Minimum net free ventilating area (attic/soffit vents) | 1/150 (or 1/300 where exception applies) | § R806.2 |
| Vent opening least dimension / screening | 1/16 in. – 1/4 in.; larger openings must be screened | § R806.1 |
Exceptions & special cases
- Prescriptive alternative for wood structural panel soffits at various wind pressures is provided in § R704.3.4 (Table R704.3.4); use that table when applicable instead of engineering to Table R301.2.1(1).
- The CRC frequently defers to manufacturer’s installation instructions when a material or assembly is not specifically listed — see both § R704.2 and § R704.3.
- Venting performance / sizing for attic spaces and enclosed soffit spaces is in § R806; R704 does not prescribe net free area or vent screening criteria, so where vent sizing/clearances are needed rely on § R806 (and WUI rules where applicable).
Common mistakes
- Confusing the two unsupported‑span thresholds: remember >16 in. applies to vinyl/aluminum in the ≤30 psf track (§ R704.2.1) but >12 in. applies when >30 psf (§ R704.3.1).
- Using non‑corrosion‑resistant fasteners for exterior soffit panels (vinyl/aluminum must use specified corrosion‑resistant fasteners). § R704.2.1.
- Omitting intermediate nailing strips when the code calls for them (span limits are explicit). § R704.2.1 and § R704.3.1.
- Treating R704 as the place for ventilation sizing — it is not; use § R806 for minimum net free ventilating area and screening.
- Applying prescriptive fastener spacing for hardboard or wood panels outside the wind‑pressure conditions for which they were written (consult § R704.2 vs § R704.3 and the prescriptive tables).
Worked example — concrete scenario
Scenario: You will install vinyl soffit panels on a single‑story house in your California city. The engineering charts give a design wind pressure = 40 psf at the soffit location.
- Because 40 psf > 30 psf, follow § R704.3 (not § R704.2). § R704.1 → § R704.3.1.
- Under § R704.3.1, vinyl panels and attachments must be capable of resisting the component/cladding wind loads calculated from Table R301.2.1(1) using an effective wind area of 10 ft² and adjusted per Table R301.2.1(2) — so verify the panel system (manufacturer acceptance/tests or design) can resist the required loads. § R704.3.1 and § R704.1.
- For unsupported span: because design wind pressure >30 psf, the code requires intermediate nailing strips when unsupported span > 12 in. (305 mm). If your panel runs across a 4‑ft eave and the panel profile results in unsupported spans of 18 in., intermediate nailing strips are required at the spacing in the figure. § R704.3.1.
- Use the fasteners specified by the manufacturer, and fasten at both ends to a supporting component (nailing strip, fascia or subfascia). § R704.3.1.
If instead the same site had a computed wind pressure of 25 psf, you would follow § R704.2.1, allow an unsupported span up to 16 in. before adding intermediate nailing strips, and use the prescriptive fastener guidance in § R704.2.1.
Related provisions
- § R704.1 — General wind limitations for exterior soffits and reference to Tables R301.2.1(1)/(2).
- § R704.2 — Soffit installation where design wind pressure is 30 psf or less.
- § R704.2.1 — Vinyl and aluminum exterior soffit panels (fasteners, unsupported spans).
- § R704.2.2 — Fiber‑cement exterior soffit panels (minimum thickness and standards).
- § R704.2.3 — Hardboard exterior soffit panels (thickness and nailing).
- § R704.2.4 — Wood structural panel exterior soffit (minimum nominal thickness and fastening).
- § R704.3 — Soffit installation where design wind pressure exceeds 30 psf.
- § R704.3.1 – R704.3.4 — Material‑specific high‑wind requirements (vinyl, fiber‑cement, hardboard, wood structural panel).
- § R806.1 – R806.5 — Roof ventilation (vent sizing, openings, screening, and WUI considerations) — apply these for soffit/eave vent sizing and protection.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 7-33 High relevance — show source text
2025 CALIFORNIA RESIDENTIAL CODE 7-33
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
R704.3 Exterior soffit installation where the design wind pressure exceeds 30 psf. Where the design wind pressure is greater than 30 psf, exterior soffit installation shall comply with Section R704.3.1, R704.3.2, R704.3.3 or R704.3.4. Exterior soffit materials not addressed in Sections R704.3.1 through R704.3.4 shall be in accordance with the manufacturer’s installation instructions.
R704.3.1 Vinyl exterior soffit panels. Vinyl exterior soffit panels and their attachments shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2). Vinyl exterior soffit panels shall be installed using fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure R704.2.1(1). Where the unsupported span of exterior soffit panels is greater than 12 inches (305 mm), intermediate nailing strips shall be provided in accordance with Figure R704.2.1(2). Vinyl exterior soffit panels shall be installed in accordance with the manufacturer’s installation instructions.
R704.3.2 Fiber-cement exterior soffit panels. F iber-cement exterior soffit panels shall comply with Section R704.2.2 and shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2).
R704.3.3 Hardboard exterior soffit panels. Hardboard exterior soffit panels shall comply with the manufacturer’s installation instructions and shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2).
R704.3.4 Wood structural panel exterior soffit. Wood structural panel exterior soffits shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2). Alternatively, wood structural panel exterior soffits shall be installed in accordance with Table R704.3.4.
|TABLE R704.3.4—PRESCRIPTIVE ALTERNATIVE FOR WOOD STRUCTURAL PANEL EXTERIOR SOFFIT b, c, d,
CRC § 1.44 High relevance — show source text
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
R703.17 Cladding attachment over foam sheathing to masonry or concrete wall construction. Cladding shall be specified and installed in accordance with Section R703.3 and the cladding manufacturer’s instructions or an approved design. Foam sheathing shall be attached to masonry or concrete construction in accordance with the insulation manufacturer’s installation instructions or an approved design. Furring and furring attachments through foam sheathing into concrete or masonry substrate shall be designed to resist design loads determined in accordance with Section R301, including support of cladding weight as applicable. Fasteners used to attach cladding or furring through foam sheathing to masonry or concrete substrates shall be approved for application into masonry or concrete material and shall be installed in accordance with the fastener manufacturer’s instructions.
Exceptions:
- Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing and connection to a masonry or concrete substrate, those requirements shall apply.
- For exterior insulation and finish systems, refer to Section R703.9.
- For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.
R703.18 Fiber-mat reinforced cementitious backer units. Fiber-mat reinforced cementitious backer units used on exterior walls as a substrate for the application of exterior finish materials shall comply with ASTM C1325. Installation shall be in accordance with the manufacturer’s installation instructions. Backer units shall be installed using corrosion-resistant fasteners. Finish materials shall be installed in accordance with the manufacturer’s instructions.
SECTION R704 —EXTERIOR SOFFITS AND FASCIAS
R704.1 General wind limitations. Where the design wind pressure is 30 pounds per square foot (1.44 kPa) or less, exterior soffits shall comply with Section R704.2. Where the design wind pressure exceeds 30 pounds per square foot (1.44 kPa), exterior soffits shall comply with Section R704.3. The design wind pressure on exterior soffits shall be determined using the component and cladding loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.93 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2).
R704.2 Exterior Soffit installation where the design wind pressure is 30 psf or less. Where the design wind pressure is 30 pounds per square foot (1.44 kPa) or less, exterior soffit installation shall comply with Section R704.2.1, R704.2.2, R704.2.3 or R704.2.4. Soffit materials not addressed in Sections R704.2.1 through R704.2.4 shall be in accordance with the manufacturer’s installation instructions.
R704.2.1 Vinyl and aluminum exterior soffit panels. Vinyl and aluminum exterior soffit panels shall be installed using aluminum, galvanized, stainless steel or rust-preventative coated nails or staples or other approved corrosion-resistant fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure R704.2.1(1). Where the unsupported span of exterior soffit panels is greater than 16 inches (406 mm), intermediate nailing strips shall be provided in accordance with Figure R704.2.1(2).
CRC § 2.1 High relevance — show source text
2.1 OR R704.3.1|R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1|R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1|FIGURE R704.2.1(2)—TYPICAL DOUBLE-SPAN VINYL AND ALUMINUM EXTERIOR SOFFIT PANEL SUPPORT
R704.2.2 Fiber-cement exterior soffit panels. Fiber-cement exterior soffit panels shall be a minimum of [1] / 4 inch (6.4 mm) in thickness and shall comply with the requirements of ASTM C1186, Type A, minimum Grade II, or ISO 8336, Category A, minimum Class 2. Panel joints shall occur over framing or over wood structural panel sheathing. Exterior soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions. R704.2.3 Hardboard exterior soffit panels. Hardboard exterior soffit panels shall be not less than [7] / 16 inch (11.11 mm) in thickness and shall be fastened to framing or nailing strips with 2 [1] / 2 -inch by 0.113-inch (64 mm by 2.9 mm) siding nails spaced not more than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports.
R704.2.4 Wood structural panel exterior soffit. The minimum nominal thickness for wood structural panel exterior soffits shall be [3] / 8 inch (9.5 mm) and shall be fastened to framing or nailing strips with 2-inch by 0.099-inch (51 mm by 2.5 mm) nails. Fasteners shall be spaced not less than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports.
2025 CALIFORNIA RESIDENTIAL CODE 7-33
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
R704.3 Exterior soffit installation where the design wind pressure exceeds 30 psf. Where the design wind pressure is greater than 30 psf, exterior soffit installation shall comply with Section R704.3.1, R704.3.2, R704.3.3 or R704.3.4. Exterior soffit materials not addressed in Sections R704.3.1 through R704.3.4 shall be in accordance with the manufacturer’s installation instructions.
R704.3.1 Vinyl exterior soffit panels. Vinyl exterior soffit panels and their attachments shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2). Vinyl exterior soffit panels shall be installed using fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure R704.2.1(1).
CRC § 2.85 High relevance — show source text
8
Screw|Steel thickness
+ 3 threads|24|2.85|DR|DR|DR|DR|2.20|DR|DR|DR|DR| |Minimum
33-mil
steel
furring or
minimum
1× wood
furringc|43-mil or
thicker
steel stud|No. 10
screw|Steel thickness
+ 3 threads|12|4.00|3.85|3.25|2.80|1.80|4.00|3.05|2.15|1.50|DR| |Minimum
33-mil
steel
furring or
minimum
1× wood
furringc|43-mil or
thicker
steel stud|No. 10
screw|Steel thickness
+ 3 threads|16|4.00|3.30|2.55|1.95|0.60|4.00|2.25|1.05|DR|DR| |Minimum
33-mil
steel
furring or
minimum
1× wood
furringc|43-mil or
thicker
steel stud|No. 10
screw|Steel thickness
+ 3 threads|24|4.00|2.25|1.05|DR|DR|4.00|0.65|DR|DR|DR|2025 CALIFORNIA RESIDENTIAL CODE 7-31
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
R703.17 Cladding attachment over foam sheathing to masonry or concrete wall construction. Cladding shall be specified and installed in accordance with Section R703.3 and the cladding manufacturer’s instructions or an approved design. Foam sheathing shall be attached to masonry or concrete construction in accordance with the insulation manufacturer’s installation instructions or an approved design. Furring and furring attachments through foam sheathing into concrete or masonry substrate shall be designed to resist design loads determined in accordance with Section R301, including support of cladding weight as applicable. Fasteners used to attach cladding or furring through foam sheathing to masonry or concrete substrates shall be approved for application into masonry or concrete material and shall be installed in accordance with the fastener manufacturer’s instructions.
Exceptions:
- Where the cladding manufacturer has provided approved installation instructions for application over foam sheathing and connection to a masonry or concrete substrate, those requirements shall apply.
- For exterior insulation and finish systems, refer to Section R703.9.
- For anchored masonry or stone veneer installed over foam sheathing, refer to Section R703.8.
R703.18 Fiber-mat reinforced cementitious backer units. Fiber-mat reinforced cementitious backer units used on exterior walls as a substrate for the application of exterior finish materials shall comply with ASTM C1325. Installation shall be in accordance with the manufacturer’s installation instructions. Backer units shall be installed using corrosion-resistant fasteners. Finish materials shall be installed in accordance with the manufacturer’s instructions.
SECTION R704 —EXTERIOR SOFFITS AND FASCIAS
CRC § 1.44 High relevance — show source text
R704.2 Exterior Soffit installation where the design wind pressure is 30 psf or less. Where the design wind pressure is 30 pounds per square foot (1.44 kPa) or less, exterior soffit installation shall comply with Section R704.2.1, R704.2.2, R704.2.3 or R704.2.4. Soffit materials not addressed in Sections R704.2.1 through R704.2.4 shall be in accordance with the manufacturer’s installation instructions.
R704.2.1 Vinyl and aluminum exterior soffit panels. Vinyl and aluminum exterior soffit panels shall be installed using aluminum, galvanized, stainless steel or rust-preventative coated nails or staples or other approved corrosion-resistant fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure R704.2.1(1). Where the unsupported span of exterior soffit panels is greater than 16 inches (406 mm), intermediate nailing strips shall be provided in accordance with Figure R704.2.1(2). Vinyl and aluminum exterior soffit panels shall be installed in accordance with the manufacturer’s installation instructions. Fascia covers shall be installed in accordance with the manufacturer’s installation instructions.
7-32 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WALL COVERING
FIGURE R704.2.1(1)—TYPICAL SINGLE-SPAN VINYL AND ALUMINUM EXTERIOR SOFFIT PANEL SUPPORT
FASCIA SHALL BE
INSTALLED IN ACCORDANCE
WITH SECTION R704.4.
ATTACH EXTERIOR
SOFFIT
TO SUB-FASCIA OR
TO NAILING STRIP (NOT SHOWN)
RDANCE
.4.
FRAMING
MIN. 1X2 NAILING
STRIPCol2 Col3 Col4 Col5 Col6 Col7 R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.CRC § 14-3 High relevance — show source text
1402 Performance Requirements . . . . . . . . . . . . . . . . . . . . 14-3
1403 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4
1404 Installation of Wall Coverings. . . . . . . . . . . . . . . . . . . 14-5
1405 Combustible Materials on the Exterior Side of
Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-16
1406 Metal Composite Material (MCM). . . . . . . . . . . . . . . 14-17
1407 Exterior Insulation and Finish Systems (EIFS). . . . 14-18
1408 High-Pressure Decorative Exterior-Grade Compact Laminates (HPL). . . . . . . . . . . . . . . . . . . 14-18
1409 Insulated Metal Panel (IMP) . . . . . . . . . . . . . . . . . . . 14-19
1410 Plastic Composite Decking . . . . . . . . . . . . . . . . . . . . 14-21 1411 Building-Integrated Photovoltaic (BIPV) Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-21
1412 Soffits and Fascias at Roof Overhangs . . . . . . . . . . 14-21
1413 [DSA-SS & DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] Additional Requirements for Anchored and Adhered Veneer. . . . . . . . . . . . . . 14-23
CHAPTER 15 ROOF ASSEMBLIES AND ROOFTOP
STRUCTURES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-1
1501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3
1502 Roof Drainage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3
1503 Weather Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-3
1504 Performance Requirements . . . . . . . . . . . . . . . . . . . . 15-3
1505 Fire Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-5
1506 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-6
1507 Requirements for Roof Coverings . . . . . . . . . . . . . . . 15-7
CRC § 2.1 High relevance — show source text
ATTACH EXTERIOR
SOFFIT
TO SUB-FASCIA OR
TO NAILING STRIP (NOT SHOWN)
RDANCE
.4.
FRAMING
MIN. 1X2 NAILING
STRIPCol2 Col3 Col4 Col5 Col6 Col7 R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1R
OR
VINYL AND ALUMINUM
EXTERIOR SOFFIT
J-CHANNEL
UNSUPPORTED SPAN
LIMITED PER SECTION R704.2.1 OR R704.3.1FIGURE R704.2.1(2)—TYPICAL DOUBLE-SPAN VINYL AND ALUMINUM EXTERIOR SOFFIT PANEL SUPPORT
R704.2.2 Fiber-cement exterior soffit panels. Fiber-cement exterior soffit panels shall be a minimum of [1] / 4 inch (6.4 mm) in thickness and shall comply with the requirements of ASTM C1186, Type A, minimum Grade II, or ISO 8336, Category A, minimum Class 2. Panel joints shall occur over framing or over wood structural panel sheathing. Exterior soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions. R704.2.3 Hardboard exterior soffit panels. Hardboard exterior soffit panels shall be not less than [7] / 16 inch (11.11 mm) in thickness and shall be fastened to framing or nailing strips with 2 [1] / 2 -inch by 0.113-inch (64 mm by 2.9 mm) siding nails spaced not more than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports.
CRC § 1409.7.2. High relevance — show source text
Exceptions:
Assemblies protected on the outside with one of the following:
- A thermal barrier complying with Section 1409.7.2.
- Concrete or masonry not less than 1 inch (25 mm) in thickness.
- Glass-fiber-reinforced concrete panels not less than [3] / 8 inch (9.5 mm) in thickness.
- Metal-faced panels having outer facings not less in thickness than 0.019 inch (0.48 mm) aluminum or 0.016 inch (0.41 mm) corrosion-resistant steel.
- Stucco not less than [7] / 8 inch (22.2 mm) in thickness, complying with Section 2510.
- Fiber-cement lap, panel or shingle siding complying with Section 1404.17 and Section 1404.17.1 or 1404.17.2, and having a thickness of not less than [1] / 4 inch (6.4 mm).
14-20 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
EXTERIOR WALLS
1409.8 Type V construction. IMP shall be permitted for use in Type V construction.
1409.9 Labeling. Unless otherwise specified, the edge or face of each IMP or package shall bear the label of an approved agency. The label shall contain the manufacturer’s or distributor’s identification, model number, serial number or definitive information describing the product or materials’ performance characteristics and approved agency’s identification.
1409.9.1 Foam plastic core. IMP having a foam plastic core shall be labeled in accordance with Sections 2603.2 and 2603.5.6, as applicable.
SECTION 1410—PLASTIC COMPOSITE DECKING
[BS] 1410.1 Plastic composite decking. Exterior deck boards, stair treads, handrails and guards constructed of plastic composites, including plastic lumber, shall comply with Section 2612.
SECTION 1411—BUILDING-INTEGRATED PHOTOVOLTAIC (BIPV) SYSTEMS FOR EXTERIOR WALL COVERINGS AND FENESTRATION
1411.1 Listing required. In addition to complying with other provisions of this code, building-integrated photovoltaic (BIPV) systems used as exterior wall coverings or fenestration shall be listed and labeled in accordance with UL 1703 or both UL 61730-1 and UL 61730-2.
SECTION 1412—SOFFITS AND FASCIAS AT ROOF OVERHANGS
1412.1 General. Soffits and fascias at roof overhangs shall be designed and constructed in accordance with the applicable provisions of this section.
1412.2 General wind requirements. Soffits and fascias shall be capable of resisting the component and cladding loads for walls determined in accordance with Chapter 16 using an effective wind area of 10 square feet (0.93 m [2] ).
1412.3 Vinyl and aluminum soffit panels. Vinyl and aluminum soffit panels shall comply with Section 1412.2, shall be installed using fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure 1412.3(1).
CRC § 304.8 High relevance — show source text
4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1 pound per square foot = 0.0479 kPa, Grade 40 = 280 MPa, Grade 60 = 420 MPa.
a. See Table R608.3 for tolerances permitted from nominal thickness.
b. Table values are based on concrete with a minimum specified compressive strength of 2,500 psi. See Note j.
c. Table values are based on uniform loading. See Section R608.8.2 for lintels supporting concentrated loads.
d. Deflection criterion is_L_/240, where_L_ is the clear span of the lintel in inches, or1/2 inch, whichever is less.
e. Linear interpolation is permitted between ground snow loads and between lintel depths.
f. DR indicates design required.
g. Lintel depth,D, is permitted to include the available height of wall located directly above the lintel, provided that the increased lintel depth spans the entire length of the
lintel.
h. Stirrups shall be fabricated from reinforcing bars with the same yield strength as that used for the main longitudinal reinforcement.
i. Allowable clear span without stirrups applicable to all lintels of the same depth,D. Top and bottom reinforcement for lintels without stirrups shall be not less than the least
amount of reinforcement required for a lintel of the same depth and loading condition with stirrups. All other spans require stirrups spaced at not more than_d_/2.
j. Where concrete with a minimum specified compressive strength of 3,000 psi is used, clear spans for lintels without stirrups shall be permitted to be multiplied by 1.05. If the
increased span exceeds the allowable clear span for a lintel of the same depth and loading condition with stirrups, the top and bottom reinforcement shall be equal to or
greater than that required for a lintel of the same depth and loading condition that has an allowable clear span that is equal to or greater than that of the lintel without stir-
rups that has been increased.
k. Center distance,A, is the center portion of the clear span where stirrups are not required. This is applicable to all longitudinal bar sizes and steel yield strengths.
l. Where concrete with a minimum specified compressive strength of 3,000 psi is used, center distance,A, shall be permitted to be multiplied by 1.10.
m.The maximum clear opening width between two solid wall segments shall be 18 feet. See Section R608.7.2.1. Lintel clear spans in the table greater than 18 feet are shown for
interpolation and information only.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound per square inch = 6.895 kPa, 1 pound per square foot = 0.0479 kPa, Grade 40 = 280 MPa, Grade 60 = 420 MPa.
a. See Table R608.3 for tolerances permitted from nominal thickness.
b. Table values are based on concrete with a minimum specified compressive strength of 2,500 psi. See Note j.
c. Table values are based on uniform loading. See Section R608.8.2 for lintels supporting concentrated loads.
d. Deflection criterion is_L_/240, where_L_ is the clear span of the lintel in inches, or1/2 inch, whichever is less.
e.CRC § 6-106 High relevance — show source text
R607 Glass Unit Masonry . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-106
R608 Exterior Concrete Wall Construction. . . . . . . . . . . . 6-107
R609 Exterior Windows and Doors. . . . . . . . . . . . . . . . . . . 6-172
R610 Structural Insulated Panel Wall Construction . . . 6-175
CHAPTER 7 WALL COVERING. . . . . . . . . . . . . . . . . . . . . . . . 7-3
R701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
R702 Interior Covering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
R703 Exterior Wall Covering . . . . . . . . . . . . . . . . . . . . . . . . . 7-10
R704 Exterior Soffits and Fascias. . . . . . . . . . . . . . . . . . . . . 7-32
R705 BIPV Systems for Exterior Wall Coverings and Fenestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-35
CHAPTER 8 ROOF-CEILING CONSTRUCTION. . . . . . . . . . . 8-3
R801 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
R802 Wood Roof Framing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
R803 Roof Sheathing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-30
R804 Cold-Formed Steel Roof Framing . . . . . . . . . . . . . . . 8-31
R805 Ceiling Finishes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44
R806 Roof Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-44
R807 Attic Access. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-46
CHAPTER 9 ROOF ASSEMBLIES . . . . . . . . . . . . . . . . . . . . . .9-3
R901 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
R902 Fire Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-3
CRC § 1403.5.3 High relevance — show source text
[BS] 1403.5.3 Lead-coated copper. Lead-coated copper shall conform to the requirements of ASTM B101.
[BS] 1403.6 Concrete. Exterior walls of concrete construction shall be designed and constructed in accordance with Chapter 19.
[BS] 1403.7 Glass-unit masonry Exterior walls of glass-unit masonry shall be designed and constructed in accordance with Chapter 21.
1403.8 Vinyl siding. Vinyl siding shall be certified and labeled as conforming to the requirements of ASTM D3679 by an approved
agency.
1403.9 Fiber-cement siding. Fiber-cement siding shall conform to the requirements of ASTM C1186, Type A (or ISO 8336, Category A), and shall be so identified on labeling listing an approved agency.
1403.10 Exterior insulation and finish systems. Exterior insulation and finish systems (EIFS) and exterior insulation and finish systems (EIFS) with drainage shall comply with Section 1407.
1403.11 Polypropylene siding. Polypropylene siding shall be certified and labeled as conforming to the requirements of ASTM D7254 and those of Section 1403.11.1 or 1403.11.2 by an approved agency. Polypropylene siding shall be installed in accordance with the requirements of Section 1404.18 and in accordance with the manufacturer’s instructions. Polypropylene siding shall be secured to the building so as to provide weather protection for the exterior walls of the building.
1403.11.1 Flame spread index. The certification of the flame spread index shall be accompanied by a test report stating that all portions of the test specimen ahead of the flame front remained in position during the test in accordance with ASTM E84 or UL 723.
1403.11.2 Fire separation distance. The fire separation distance between a building with polypropylene siding and the adjacent building shall be not less than 10 feet (3048 mm).
1403.12 Foam plastic insulation. Foam plastic insulation used in exterior wall assemblies shall comply with Chapter 26.
1403.13 Fiber-mat reinforced cementitious backer units. Fiber-mat reinforced cementitious backer units used as an exterior substrate for the application of exterior finish materials shall comply with ASTM C1325.
1403.14 Insulated vinyl siding. Insulated vinyl siding shall be certified and labeled as conforming to the requirements of ASTM D7793 by an approved agency.
SECTION 1404—INSTALLATION OF WALL COVERINGS
1404.1 General. Exterior wall coverings shall be designed and constructed in accordance with the applicable provisions of this section.
1404.1.1 Soffits and fascias. Soffits and fascias installed as part of roof overhangs shall comply with Section 1412.
1404.1.2 Additional requirements. [DSA-SS, DSA-SS/CC, OSHPD 1, 1R, 2, 4 & 5] In addition to the requirements of Section 1404, the installation of anchored or adhered veneer shall comply with applicable provisions of Section 1413.
1404.2 Weather protection. 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.
2025 CALIFORNIA BUILDING CODE 14-5
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
CRC § 0.113 High relevance — show source text
or 16 ga.
staple galvanized, 15/8″ long,7/16″ or
1″ crown; or 15/8″ screws, Type W or S|7|7| |Wood structural panels, combination subfloor underlayment to framing|Wood structural panels, combination subfloor underlayment to framing|Wood structural panels, combination subfloor underlayment to framing|Wood structural panels, combination subfloor underlayment to framing|Wood structural panels, combination subfloor underlayment to framing| |38|3/4″ and less|Deformed (2″ × 0.113″) or
Deformed (2″ × 0.120″) nail; or
8d common (21/2″ × 0.131″) nail|6|12| |39|7/8″ – 1"|8d common (21/2″ × 0.131″) nail; or
Deformed (21/2″ × 0.131″); or
Deformed (21/2″ × 0.120″) nail|6|12| |40|11/8″ − 11/4″|10d common (3″ × 0.148″) nail; or
Deformed (21/2″× 0.131″); or
Deformed (21/2″ × 0.120″) nail|6|12| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s; 1 ksi = 6.895 MPa.
a. Nails are smooth-common, box or deformed shanks except where otherwise stated. Nails used for framing and sheathing connections are carbon steel and shall have mini-
mum average bending yield strengths as shown: 80 ksi for shank diameter of 0.192 inch (20d common nail), 90 ksi for shank diameters larger than 0.142 inch but not larger than
0.177 inch, and 100 ksi for shank diameters of 0.142 inch or less. Connections using nails and staples of other materials, such as stainless steel, shall be designed by accepted
engineering practice or approved under Section R104.2.2.
b. RSRS-01 is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
c. Nails shall be spaced at not more than 6 inches on center at all supports where spans are 48 inches or greater.
d. Four-foot by 8-foot or 4-foot by 9-foot panels shall be applied vertically.
e. Spacing of fasteners not included in this table shall be based on Table R602.3(2).
f. For wood structural panel roof sheathing attached to gable end roof framing and to intermediate supports within 48 inches of roof edges and ridges, nails shall be spaced at 4
inches on center where the ultimate design wind speed is greater than 130 mph in Exposure B or greater than 110 mph in Exposure C. Fastener spacing applies where roof
framing specific gravity is 0.42 or larger. Where roof framing specific gravity is greater than or equal to 0.35 but less than 0.42 in accordance with AWC NDS, fastening of roof
sheathing shall be with RSRS-03 (21/2″ × 0.131″ × 0.281″ head) nails.
g.CRC § 2.1 High relevance — show source text
Where the unsupported span of exterior soffit panels is greater than 12 inches (305 mm), intermediate nailing strips shall be provided in accordance with Figure R704.2.1(2). Vinyl exterior soffit panels shall be installed in accordance with the manufacturer’s installation instructions.
R704.3.2 Fiber-cement exterior soffit panels. F iber-cement exterior soffit panels shall comply with Section R704.2.2 and shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2).
R704.3.3 Hardboard exterior soffit panels. Hardboard exterior soffit panels shall comply with the manufacturer’s installation instructions and shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2).
R704.3.4 Wood structural panel exterior soffit. Wood structural panel exterior soffits shall be capable of resisting wind loads specified in Table R301.2.1(1) for walls using an effective wind area of 10 square feet (0.929 m [2] ) and adjusted for height and exposure in accordance with Table R301.2.1(2). Alternatively, wood structural panel exterior soffits shall be installed in accordance with Table R704.3.4.
TABLE R704.3.4—PRESCRIPTIVE ALTERNATIVE FOR WOOD STRUCTURAL PANEL EXTERIOR SOFFIT b, c, d, e Col2 Col3 Col4 Col5 Col6 MAXIMUM DESIGN
PRESSURE
(+ or - psf)MINIMUM
PANEL SPAN
RATINGMINIMUM PANEL
PERFORMANCE
CATEGORYNAIL TYPE
AND SIZEFASTENERa SPACINGe ALONG
EDGES AND INTERMEDIATE SUPPORTS
(inches)FASTENERa SPACINGe ALONG
EDGES AND INTERMEDIATE SUPPORTS
(inches)MAXIMUM DESIGN
PRESSURE
(+ or - psf)MINIMUM
PANEL SPAN
RATINGMINIMUM PANEL
PERFORMANCE
CATEGORYNAIL TYPE
AND SIZEGalvanized Steel Stainless Steel 30 24/0 3/8 6d box
(2 × 0.099 × 0.266 head diameter)6f 4 40 24/0 3/8 6d box
(2 × 0.099 × 0.266 head diameter)6 4 50 24/0 3/8 6d box
(2 × 0.099 × 0.266 head diameter)4 4 50 24/0 3/8 8d common
(21/2 × 0.131 × 0.CRC § 1.44 High relevance — show source text
Where the unsupported span of soffit panels is greater than 12 inches (406 mm) and the design wind pressure is greater than 30 psf (1.44 kN/m [2] ) or the unsupported span of soffit panels is greater than 16 inches (406 mm) and the wind pressure is 30 psf (1.44 kN/m [2] ) or less, intermediate nailing strips shall be provided in accordance with Figure 1412.3(2). Vinyl and aluminum soffit panels shall be installed in accordance with the manufacturer’s installation instructions.
FIGURE 1412.3(1)—SINGLE-SPAN VINYL OR ALUMINUM SOFFIT PANEL SUPPORT
For SI: 1 inch = 25.4 mm.
2025 CALIFORNIA BUILDING CODE 14-21
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
EXTERIOR WALLS
FIGURE 1412.3(2)—DOUBLE-SPAN VINYL OR ALUMINUM SOFFIT PANEL SUPPORT
For SI: 1 inch = 25.4 mm.
1412.4 Fiber-cement soffit panels. Fiber-cement soffit panels shall comply with Section 1412.2, shall be not less than [1] / 4 inch (6.4 mm) in thickness and shall comply with the requirements of ASTM C1186, Type A, minimum Grade II, or ISO 8336, Category A, minimum Class 2. Panel joints shall occur over framing or over wood structural panel sheathing. Soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions.
1412.5 Hardboard soffit panels. Hardboard soffit panels shall comply with Section 1412.2 and shall be not less than [7] / 16 inch (11.11 mm) in thickness and fastened to framing or nailing strips to meet the required design wind pressures. Where the design wind pressure is 30 pounds per square foot (1.44 kN/m [2] ) or less, hardboard soffit panels are permitted to be attached to wood framing with 2 [1] / 2 -inch by 0.113-inch (64 mm by 2.9 mm) siding nails spaced not more than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports. Soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions.
1412.6 Wood structural panel soffit. Wood structural panel soffits shall comply with Section 1412.2 and shall have minimum panel performance category of [3] / 8 . Wood structural panel soffits are permitted to be attached to wood framing in accordance with Table 1412.6.
|TABLE 1412.6—PRESCRIPTIVE ALTERNATE FOR WOOD STRUCTURAL PANEL SOFFITb, c, d,
CRC § 2.2 Medium relevance — show source text
Design criteria R301.1, R301.2.2, R301.3
Service Utilities R111
Shakes
Wood R702.6, R703.6, R905.8 Shingle Asphalt shingles R905.2 Metal R905.4
Slate R905.6
Wood R905.7 Ship’s Ladders (see Ladders) R318.7.13 Shower R326.1, R327 Compartment R327.2 Finishes R327.2 Glazing R324.3.1, R324.4.5 Space required R327.1 Shutoff Valve (see Valves) Siding Exterior coverings R703 Sinks (see also Lavatories) R326.2 Site
Address R308
Preparation R408.5, R504.2, R506.3 Size
Of rooms R312 Skylights R324.6
Slate Shingles R905.6 Sleeping Lofts R315 Smoke Alarms R310
Smoke-Developed Index R302.10, R302.9 Snow Loads R301.1, Figure R301.2(3) Decks R507.1, R507.5, R507.6 Floors R502.3.3, R505.1.1 Foundation R403.1
Roof R301.6, R329.4.1.1, R802.10.2.1, R802.4.1, R804.3.2.1 Walls R602.3.1, R602.7, R603.3.2 Soffit R704
Fiber-cement R704.2.2, R704.3.2 Hardboard R704.2.3, R704.3.3 Vinyl R704.2.1, R704.3.1 Wood R704.2.4, R704.3.4 Solar Energy Systems R329 Building-integrated photovoltaic systems R329.5 Ground-mounted photovoltaic systems R329.8 Photovoltaic systems R329.3 Roof access and pathways R329.6 Rooftop-mounted photovoltaic systems R329.3 Sound Transmission Appendix BG Spans Steel (allowable) R505.3.2, R804.3.2.1 Wood (allowable) R502.3, R802.5 Sprinkler (see Automatic Sprinkler System) Stairways R318.7 Alternating tread devices R318.7.12 Bulkhead enclosure R318.7.11.2 Glazing R324.4.6 Guards R321
Handrails R318.7.8, R320 Headroom R318.7.2
Illumination R318.7.10, R325.6, R325.7 Landings for R318.7.6 Nosings R318.7.5.3 Ship’s ladders R318.7.13 Sleeping lofts R315.5.2 Spiral R318.7.11 Treads and risers R318.7.5, R318.7.5.4 Vertical egress R318.4 Vertical rise R318.7.3 Walking surface slope R318.7.7 Walkline R318.7.4
Width R318.7.1
CRC § 12-7 Medium relevance — show source text
SFM STANDARD 12-7A-3
12-7A-3.1 Application. The minimum design, construction and performance standards set forth herein for the exposed underside of horizontal projections such as the horizontal soffits of roof eaves, floor projections and exposed underfloor areas are those deemed necessary to establish conformance to the provisions of these regulations. Materials and assemblies that meet the performance criteria of this standard are acceptable for use as defined in the California Building Standards Code.
12-7A-3.2 Scope. This standard evaluates the fire-resistive performance of horizontal projection assemblies including the horizontal soffits of roof eaves, floor projections and exposed underfloor areas when subjected to direct flame exposure to the underside of a horizontal projection.
12-7A-3.3 Referenced documents.
ASTM D4442, Test Methods for Direct Moisture Content Measurement of Wood and Wood-Base Materials.
ASTM D4444, Test Methods for Use and Calibration of Hand-Held Moisture Meters.
California Building Code, Chapter 7A.
12-7A-3.4 Definitions.
- Eaves. A projecting edge of a roof that extends beyond the supporting wall as in CBC 702A “Roof Eave” or similar horizontal projection assembly.
- Soffit. The enclosed underside of any exterior overhanging section of a roof eave or similar horizontal projection assembly (see CBC 702A “Roof Eave Soffit”).
12-7A-3.5 Equipment.
- Burner. A 12 by 12-inch (300 by 300 mm) diffusion burner shall be used. Natural gas, methane or propane shall be supplied to the burner through a metered control system. The gas supply to the burner shall produce a net heat output of 300 ± 15 kW throughout the flame exposure. Burner output can be determined from HRR or calculated from the gas flow rate, temperature and pressure.
- Infrared temperature analyzer (optional). Intended for monitoring the temperature change of the inside of the eaves.
- Moisture content. Prior to testing, all materials (lumber and soffit material) shall be conditioned to a constant weight or for a minimum of 30 days at 73 ± 4°F (23 ± 2°C) and 50 ± 5% relative humidity, whichever occurs first. Constant weight shall be defined as occurring when the change in test material weight is less than or equal to 2 percent in a 24-hour period. Lumber moisture content shall be between 8 and 12 percent (oven-dry basis) and sheathing shall not exceed 8 percent (oven-dry basis).
12-7A-3.6 Materials.
Framing. The materials used shall be representative of the grades that would be typical of eave construction and installed in the eave’s subassembly as per accepted construction practices.
Soffit. Material selected for the test.
12-7A-3.7 Test system preparation (Figure 1).
- Eaves fabrication. The 4-foot-wide by 2-foot (1.2 m by 0.6 m) test specimen shall be constructed to fit into a 4-foot-wide (1.2 m) space at the top of the test assembly described in SFM 12-7A-1.
CRC § 1412.5 Medium relevance — show source text
1412.5 Hardboard soffit panels. Hardboard soffit panels shall comply with Section 1412.2 and shall be not less than [7] / 16 inch (11.11 mm) in thickness and fastened to framing or nailing strips to meet the required design wind pressures. Where the design wind pressure is 30 pounds per square foot (1.44 kN/m [2] ) or less, hardboard soffit panels are permitted to be attached to wood framing with 2 [1] / 2 -inch by 0.113-inch (64 mm by 2.9 mm) siding nails spaced not more than 6 inches (152 mm) on center at panel edges and 12 inches (305 mm) on center at intermediate supports. Soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions.
1412.6 Wood structural panel soffit. Wood structural panel soffits shall comply with Section 1412.2 and shall have minimum panel performance category of [3] / 8 . Wood structural panel soffits are permitted to be attached to wood framing in accordance with Table 1412.6.
TABLE 1412.6—PRESCRIPTIVE ALTERNATE FOR WOOD STRUCTURAL PANEL SOFFITb, c, d, e Col2 Col3 Col4 Col5 Col6 MAXIMUM
DESIGN
PRESSURE
(± psf)MINIMUM PANEL
SPAN RATINGMINIMUM PANEL
PERFORMANCE
CATEGORYNAIL TYPE AND SIZE FASTENERa SPACING ALONG EDGES
AND INTERMEDIATE SUPPORTSFASTENERa SPACING ALONG EDGES
AND INTERMEDIATE SUPPORTSMAXIMUM
DESIGN
PRESSURE
(± psf)MINIMUM PANEL
SPAN RATINGMINIMUM PANEL
PERFORMANCE
CATEGORYNAIL TYPE AND SIZE Galvanized steel Stainless steel 30 24/0 3/8 6d box
(2″ × 0.099″ × 0.266″ head diameter)6f 4 40 24/0 3/8 6d box
(2″ × 0.099″ × 0.266″ head diameter)6 4 50 24/0 3/8 6d box
(2″ × 0.099″ × 0.266″ head diameter)4 4 50 24/0 3/8 8d common
(21/2″ × 0.131″ × 0.281″ head diameter)6 6 60 24/0 3/8 6d box
(2″ × 0.099″ × 0.266″ head diameter)4 3 60 24/0 3/8 8d common
(21/2″ × 0.131″ × 0.281″ head diameter)6 4 70 24/16 7/16 8d common
(21/2″ × 0.131″ × 0.CRC § 1410.1 Medium relevance — show source text
SECTION 1410—PLASTIC COMPOSITE DECKING
[BS] 1410.1 Plastic composite decking. Exterior deck boards, stair treads, handrails and guards constructed of plastic composites, including plastic lumber, shall comply with Section 2612.
SECTION 1411—BUILDING-INTEGRATED PHOTOVOLTAIC (BIPV) SYSTEMS FOR EXTERIOR WALL COVERINGS AND FENESTRATION
1411.1 Listing required. In addition to complying with other provisions of this code, building-integrated photovoltaic (BIPV) systems used as exterior wall coverings or fenestration shall be listed and labeled in accordance with UL 1703 or both UL 61730-1 and UL 61730-2.
SECTION 1412—SOFFITS AND FASCIAS AT ROOF OVERHANGS
1412.1 General. Soffits and fascias at roof overhangs shall be designed and constructed in accordance with the applicable provisions of this section.
1412.2 General wind requirements. Soffits and fascias shall be capable of resisting the component and cladding loads for walls determined in accordance with Chapter 16 using an effective wind area of 10 square feet (0.93 m [2] ).
1412.3 Vinyl and aluminum soffit panels. Vinyl and aluminum soffit panels shall comply with Section 1412.2, shall be installed using fasteners specified by the manufacturer and shall be fastened at both ends to a supporting component such as a nailing strip, fascia or subfascia component in accordance with Figure 1412.3(1). Where the unsupported span of soffit panels is greater than 12 inches (406 mm) and the design wind pressure is greater than 30 psf (1.44 kN/m [2] ) or the unsupported span of soffit panels is greater than 16 inches (406 mm) and the wind pressure is 30 psf (1.44 kN/m [2] ) or less, intermediate nailing strips shall be provided in accordance with Figure 1412.3(2). Vinyl and aluminum soffit panels shall be installed in accordance with the manufacturer’s installation instructions.
FIGURE 1412.3(1)—SINGLE-SPAN VINYL OR ALUMINUM SOFFIT PANEL SUPPORT
For SI: 1 inch = 25.4 mm.
2025 CALIFORNIA BUILDING CODE 14-21
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
EXTERIOR WALLS
FIGURE 1412.3(2)—DOUBLE-SPAN VINYL OR ALUMINUM SOFFIT PANEL SUPPORT
For SI: 1 inch = 25.4 mm.
1412.4 Fiber-cement soffit panels. Fiber-cement soffit panels shall comply with Section 1412.2, shall be not less than [1] / 4 inch (6.4 mm) in thickness and shall comply with the requirements of ASTM C1186, Type A, minimum Grade II, or ISO 8336, Category A, minimum Class 2. Panel joints shall occur over framing or over wood structural panel sheathing. Soffit panels shall be installed with spans and fasteners in accordance with the manufacturer’s installation instructions.
Frequently asked questions
Do soffit vents have to be a certain size or screening per the soffit sections?
No — § R704 does not set vent sizes. Vent sizing, minimum net free area (1/150 or 1/300 exception) and screening dimensions are in § R806 (Roof Ventilation). For WUI areas see the California WUI code and § R806.1.1.
If a manufacturer gives a different span or fastener spacing than the CRC prescriptive tables, which controls?
If the material is not specifically addressed by the prescriptive subsections or the manufacturer provides approved installation instructions, the CRC allows following the manufacturer’s installation instructions — but in high‑wind locations you still must meet the required wind resistance per § R704.3 or the manufacturer must demonstrate compliance. § R704.2 and § R704.3.
What fasteners are required for vinyl/aluminum soffits?
Use corrosion‑resistant fasteners — aluminum, galvanized, stainless or rust‑preventative coated nails or staples or other approved corrosion‑resistant fasteners specified by the manufacturer. § R704.2.1.
Are there different rules for soffits on a tall multi‑story house vs a one‑story house?
The governing differential is the computed design wind pressure (Table R301.2.1(1)/(2) adjustments account for height and exposure). Higher pressures (often on taller buildings/exposed sites) move the project into § R704.3. § R704.1.
Can I use a prescriptive table for wood panels instead of engineering?
Yes — § R704.3.4 provides a prescriptive alternative (Table R704.3.4) for wood structural panel exterior soffits when the table conditions are met. Otherwise design to the wind loads in Table R301.2.1(1).
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