CRC · California Residential Code
Floor sheathing: materials, thickness and fastening
Homeowner summary: The California Residential Code requires you to use the correct subfloor material and thickness for your joist spacing (see § R503 and § R503.2), put panel ends over joists (unless end‑matched), and fasten panels with the nail type and closer spacing at edges than in the field (typical: 8d nails at 6" o.c. edges / 12" o.c. field for 3/4" panels). Always check the tables in the Code for the exact panel grade, thickness and fastening schedule for your situation.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
In plain English: use the minimum lumber or wood structural panel thickness and the fastening pattern required by the California Residential Code for floor sheathing. The code controls minimum lumber thickness and end‑joint placement in § R503.1 and identifies required panel grades, allowable panel thicknesses/spans and subfloor grades in § R503.2. Follow the panel fastening/fastener‑type and spacing schedules referenced by those sections (tables in Chapter 6) when attaching wood structural panels to framing. § R503.1 ; § R503.2 .
The single most important rule: provide the minimum panel or lumber thickness for the joist spacing you have, place end joints over supports (unless end‑matched), and fasten panels with the nail type and edge/field spacing the code table requires. § R503 and § R503.2 set the thickness/grade rules and point you to the fastening schedule.
Requirements in detail
1) Material identification and grade (what sheathing may be used)
- Wood structural panels used for structural subflooring must conform to accepted standards (CSA O325, CSA O437, DOC PS 1 or DOC PS 2) and be identified by a grade mark or certificate; the panel Performance Category value is used as the panel thickness wherever the Code references panel thickness. § R503.2.1 .
- Lumber sheathing (solid board subflooring) is permitted; its allowable spans/thicknesses are set in § R503.1 and the associated tables. § R503.1 .
2) Minimum thickness for lumber sheathing (decision rule)
The Code gives minimum net thickness for lumber subfloor applied either perpendicular or diagonal to joists (Table R503.1). Important entries (use the table in § R503.1 to look up your exact spacing):
| Joist or beam spacing | Minimum net thickness (perpendicular to joist) | Minimum net thickness (diagonal to joist) | Code Reference |
|---|---|---|---|
| 16 inches o.c. | 5/8 inch | 5/8 inch | § R503.1 |
| 24 inches o.c. | 11/16 inch | 3/4 inch | § R503.1 |
| Larger support spacings (48 in. and greater) require special Fb / E values or T&G boards — see § R503.1 and the table notes. | § R503.1 |
- End joints in lumber subflooring must occur over supports unless the lumber is end‑matched; end‑matched pieces must bear on at least two joists. § R503.1.1 .
3) Wood structural panel (panelized) subfloor: allowable thicknesses & spans
- Wood structural panel grades and span ratings (used to determine allowable spans and the nominal panel thickness) are listed in Table R503.2.1.1(1) and related tables; use the table to pick the panel thickness/span rating for your joist spacing and loading. § R503.2.1.1 .
- The Code expressly permits using the panel Performance Category as the “nominal panel thickness” for code references. § R503.2.1 .
4) Fastening: fastener type, edge vs field spacing, and placement
- Panel fastening (nail/staple/screw type and spacing at edges and intermediate supports) is given in the Code’s fastening schedules (referenced by the floor sheathing provisions). Typical, decision‑relevant entries from the fastening schedule (Table R602.3(2)/related tables) are:
| Panel thickness (nominal) | Typical minimum fastener | Spacing at edges (o.c.) | Spacing at intermediate supports (o.c.) | Code Reference |
|---|---|---|---|---|
| 3/8" – 1/2" | 6d common (≈2" × 0.113") | 6 inches | 12 inches | Table R602.3(2) as referenced by § R503 |
| 19/32" – 3/4" (typical 3/4" subfloor) | 8d common (2-1/2" × 0.131") | 6 inches | 12 inches | Table R602.3(2) / R2304 fastener schedule |
| 7/8" – 1-1/4" | 10d common (3" × 0.148") | 6 inches | 12 inches | Table R602.3(2) |
- Where spans are very wide (for example panels supported at 48 inches or greater), the Code requires closer spacing at supports (nails at not more than 6 inches o.c. at all supports for long spans) — see table notes.
- The Code requires panels be applied with a grid of fasteners (edges and field) and notes that edge fastening applies to panel edges supported by framing or required blocking; floor perimeters must be supported by framing or solid blocking. § R503 notes and Table references.
5) Fastener material and performance
- Nails used for framing and sheathing connections are carbon steel and the Code lists minimum average bending yield strengths correlated to shank diameters (e.g., 80 ksi for certain sizes). Alternative materials (stainless, other) must be designed/approved. See fastening notes in the schedule referenced by § R503. .
Exceptions & special cases
- End‑matched lumber: when end‑matched lumber is used, end joints need not fall over a support provided each piece bears on not less than two joists. § R503.1.1 .
- Long support spacings (48 in. and larger): the lumber/panel must meet higher bending (Fb) and stiffness (E) values shown in table notes — check the specific table notes for the required Fb/E values. § R503.1 table notes.
- Roof vs floor fastener variations: some fastener allowances (e.g., special ring‑shank nails RSRS) or reduced spacing are specifically for roof sheathing; apply the floor sheathing rows and notes, not the roof‑specific rows. The floor rules point to the general fastening schedule in Chapter 6. § R503 and related table notes.
- High wind / seismic / species exceptions: certain fastening allowances change for high wind or for framing species with specific gravity below limits — the fastening schedules include these conditional notes. Use the table notes when in high wind/seismic areas.
Common mistakes
- Relying on manufacturer thickness only: the Code requires the listed minimum nominal or net thickness for the joist spacing; don’t substitute unless you can show the panel/board meets the Code grade/performance. § R503.1 and § R503.2.1.
- Using the wrong spacing for edges vs field: many installers use a single spacing everywhere. The Code requires closer spacing at edges (commonly 6 in. o.c.) vs 12 in. in the field for many panel thicknesses — check the table entry for your panel thickness.
- Missing blocking at unsupported panel edges: panel edge fastening applies only where panel edges are supported by framing or blocking. Unsupported edges at the perimeter must be supported (blocking) or re‑designed. § R503 notes and table references.
- Incorrect fastener type or insufficient penetration: use the nail size/type listed (e.g., 8d common, 2‑1/2") so required penetration and withdrawal capacity are met. The fastening schedule lists nail sizes and types.
Worked example — concrete scenario
Scenario: 3/4" OSB subfloor (nominal 23/32" or 19/32"–3/4" range), installed over 16‑inch o.c. joists.
- Thickness/grade: a 3/4" OSB panel (proper grade/Performance Category per § R503.2.1.1) is acceptable for common floor spans — confirm the panel's span rating in Table R503.2.1.1(1). § R503.2.1 .
- Fasteners: per the fastening schedule, for panels in the 19/32" – 3/4" range use 8d common nails (≈2‑1/2" × 0.131") (or deformed equivalent). Fasten at 6 inches o.c. along panel edges and 12 inches o.c. at intermediate supports (field). Use carbon‑steel nails meeting the strength requirements in the fastener notes. Table R602.3(2) and the wood fastening schedule.
- End joints: make sure panel end joints fall over joists or blocking (or use end‑matched panels where each piece bears on two joists). § R503.1.1
Result: 3/4" OSB installed perpendicular to 16" o.c. joists, nailed with 8d @ 6" (edges) / 12" (field), with panel end joints over joists — meets the Code tables referenced by § R503/§ R503.2.
Related provisions
- § R503.1 — Lumber sheathing minimum thickness and spans.
- § R503.1.1 — End joint requirements (lumber subfloor).
- § R503.2 — Wood structural panel identification, grade and subfloor tables.
- Table references / fastening schedules (Chapter 6) — Table R602.3(2) / fastener tables for panel to framing (used by R503).
- Fastener material / nail strength notes — fastener notes in the fastening schedules.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
California Residential Code High relevance — show source text
; 2′6″ C.R.S. with 1″ cover on
both top and bottom flanges; 12′ span
simply supported.|115 psf|29 min|||7|1, 5,
13|1/4| |F/C-6-RC-31|6″|6″ deep (3450 psi) concrete deck; 4″ ×
13/4″ × 5 lbs R.S.J.; 2′6″ C.R.S. with 1″ cover
on both top and bottom flanges; 12′ span
simply supported.|25 psf|3 hrs
35 min|||7|1, 2|31/2| |F/C-6-RC-32|6″|6″ deep (4460 psi) concrete deck; 4″ ×
13/4″ × 5 lbs R.S.J.; 2′ C.R.S. with 1″ cover
on both top and bottom flanges; 12′ span
simply supported.|60 psf|4 hrs
30 min|||7|1, 10|41/2| |F/C-6-RC-33|6″|6″ deep (4360 psi) concrete deck; 4″ × 13/4″
× 5 lbs R.S.J.; 2′ C.R.S. with 1″ cover on
both top and bottom flanges; 13′1″ span
restrained.|60 psf|2 hrs|||7|1, 3|2| |F/C-6-RC-34|61/4″|61/4″ thick; 43/4″ (5120 psi) concrete core;
1″ T&G board flooring;1/2″ plaster under-
coat; 4″ × 3″ × 10 lbs R.S.J.; 3′ C.R.S. flush
with top surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|4 hrs|||7|1, 7|4| |F/C-6-RC-35|61/4″|43/4″ (3600 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S. flush with top
surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|2 hrs
30 min|||7|1, 5|21/2| |F/C-6-RC-36|61/4″|43/4″ (2800 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S.CRC § 0.164 High relevance — show source text
8 screw (0.164″ min. dia.)|16″ o.c.| |For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.479 kPa.
a. Fastener length shall be sufficient to penetrate the back side of the wood structural panel sheathing by at least1/4 inch. The wood structural panel sheathing shall be not less
than7/16 inch in thickness.
b. Spacing of fasteners is per 12 inches of siding width. For other siding widths, multiply “Spacing of Fasteners” above by a factor of 12/s, where “s” is the siding width in inches.
Fastener spacing shall never be greater than the manufacturer’s minimum recommendations.|For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.479 kPa.
a. Fastener length shall be sufficient to penetrate the back side of the wood structural panel sheathing by at least1/4 inch. The wood structural panel sheathing shall be not less
than7/16 inch in thickness.
b. Spacing of fasteners is per 12 inches of siding width. For other siding widths, multiply “Spacing of Fasteners” above by a factor of 12/s, where “s” is the siding width in inches.
Fastener spacing shall never be greater than the manufacturer’s minimum recommendations.|For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.479 kPa.
a. Fastener length shall be sufficient to penetrate the back side of the wood structural panel sheathing by at least1/4 inch. The wood structural panel sheathing shall be not less
than7/16 inch in thickness.
b. Spacing of fasteners is per 12 inches of siding width. For other siding widths, multiply “Spacing of Fasteners” above by a factor of 12/s, where “s” is the siding width in inches.
Fastener spacing shall never be greater than the manufacturer’s minimum recommendations.|R703.3.4 Minimum fastener length and penetration. Fasteners shall have the greater of the minimum length specified in Table R703.3(1) or as required to provide a minimum penetration into framing as follows:
Fasteners for horizontal aluminum siding, steel siding, particleboard panel siding, wood structural panel siding in accordance with ANSI/APA-PRP 210, fiber-cement panel siding and fiber-cement lap siding installed over foam plastic sheathing shall penetrate not less than 1 [1] / 2 inches (38 mm) into framing or shall be in accordance with the manufacturer’s installation instructions.
Fasteners for hardboard panel and lap siding shall penetrate not less than 1 [1] / 2 inches (38 mm) into framing.
Fasteners for vinyl siding and insulated vinyl siding shall be installed in accordance with Section R703.11 or R703.13.
Fasteners for polypropylene siding shall be installed in accordance with Section R703.14.
Fasteners for vertical or horizontal wood siding shall penetrate not less than 1 [1] / 2 inches (38 mm) into studs, studs and wood sheathing combined, or blocking.
Fasteners for siding material installed over foam plastic sheathing shall have sufficient length to accommodate foam plastic sheathing thickness and to penetrate framing or sheathing and framing combined, as specified in Items 1 through 5.
California Residential Code High relevance — show source text
; 2′ C.R.S. with 1″ cover on
both top and bottom flanges; 13′1″ span
restrained.|60 psf|2 hrs|||7|1, 3|2| |F/C-6-RC-34|61/4″|61/4″ thick; 43/4″ (5120 psi) concrete core;
1″ T&G board flooring;1/2″ plaster under-
coat; 4″ × 3″ × 10 lbs R.S.J.; 3′ C.R.S. flush
with top surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|4 hrs|||7|1, 7|4| |F/C-6-RC-35|61/4″|43/4″ (3600 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S. flush with top
surface concrete; 12′ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|100 psf|2 hrs
30 min|||7|1, 5|21/2| |F/C-6-RC-36|61/4″|43/4″ (2800 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat; 4″ ×
3″ × 10 lbs R.S.J.; 3′ C.R.S. flush with top
surface concrete; 12″ span simply
supported; 2″ × 1′3″ clinker concrete
insert.|80 psf|4 hrs|||7|1, 7|4| |F/C-7-RC-37|7″|(3640 psi) concrete deck;1/4″ reinforce-
ment bars at 6″ pitch with 11/2″ cover;1/4″
reinforcement bars at 5″ pitch perpendic-
ular with 11/2″ cover; 13′1″ span
restrained.|169 psf|6 hrs|||7|1, 14|6| |F/C-7-RC-38|7″|(4060 psi) concrete deck; 4″ × 3″ × 10 lbs
R.S.J.; 2′6″ C.R.S. with 11/2″ cover on both
top and bottom flanges; 4″ × 6″ × 13 SWG
mesh reinforcement 11/2″ from bottom of
slab; 13′1″ span restrained.|175 psf|6 hrs|||7|1, 14|6| |F/C-7-RC-39|71/4″|53/4″ (4010 psi) concrete core; 1″ T&G
board flooring;1/2″ plaster undercoat;
4″ × 3″ × 10 lbs R.S.J.; 2′6″ C.R.S.CRC § 3.3. High relevance — show source text
= On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|For SI: 1 inch = 25.4 mm, 1 mil = 0.0254 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Steel framing shall be minimum 33-ksi steel for 33-mil and 43-mil steel, and 50-ksi steel for 54-mil steel or thicker.
b. Where cladding is attached to wood structural panel sheathing only, fastening requirements shall be in accordance with Table R703.3.3. For brick veneer tie connections to
wood structural panels, refer to Table R703.8.4(2).
c. Screws shall comply with the requirements of ASTM C1513.
d. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.|R703.16.2 Furred cladding attachment. Where steel or wood furring is used to attach cladding over foam sheathing, furring minimum fastening requirements to support the cladding weight shall be as specified in Table R703.16.2. Where placed horizontally, wood furring shall be preservative-treated wood in accordance with Section R304.1 or naturally durable wood and fasteners shall be corrosion resistant in accordance with Section R304.3. Steel furring shall have a minimum G60 galvanized coating.
|TABLE R703.16.2—FURRING MINIMUM FASTENING REQUIREMENTS FOR
APPLICATION OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDINGCRC § 4.4. High relevance — show source text
4.4. Bottom chord dead load.
2025 CALIFORNIA RESIDENTIAL CODE 5-11
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
FLOORS
4.5. Concentrated loads and their points of application. 4.6. Controlling wind and earthquake loads. 5. Adjustments to lumber and joint connector design values for conditions of use.
Each reaction force and direction.
Joint connector type and description, such as size, thickness or gage, and the dimensioned location of each joint connector except where symmetrically located relative to the joint interface.
Lumber size, species and grade for each member.
Connection requirements for: 9.1. Truss-to-girder-truss. 9.2. Truss ply-to-ply. 9.3. Field splices.
Calculated deflection ratio, maximum description for live and total load, or both.
Maximum axial compression forces in the truss members to enable the building designer to design the size, connections and anchorage of the permanent continuous lateral bracing. Forces shall be shown on the truss drawing or on supplemental documents.
Required permanent truss member bracing location.
R502.13 Draftstopping required. Draftstopping shall be provided in accordance with Section R302.12.
R502.14 Fireblocking required. Fireblocking shall be provided in accordance with Section R302.11.
SECTION R503—FLOOR SHEATHING
R503.1 Lumber sheathing. Maximum allowable spans for lumber used as floor sheathing shall conform to Tables R503.1, R503.2.1.1(1) and R503.2.1.1(2).
TABLE R503.1—MINIMUM THICKNESS OF LUMBER FLOOR SHEATHING Col2 Col3 JOIST OR BEAM SPACING
(inches)MINIMUM NET THICKNESS MINIMUM NET THICKNESS JOIST OR BEAM SPACING
(inches)Perpendicular to joist Diagonal to joist 24 11/16 3/4 16 5/8 5/8 48a 11/2 T & G N/A 54b 54b 54b 60c 60c 60c For SI: 1 inch = 25.4 mm, 1 pound per square inch = 6.895 kPa.
N/A = Not Applicable.
a. For this support spacing, lumber sheathing shall have a minimum_Fb_ of 675 and minimum E of 1,100,000 (see ANSI AWC NDS).
b. For this support spacing, lumber sheathing shall have a minimum_Fb_ of 765 and minimum E of 1,400,000 (see ANSI AWC NDS).
c. For this support spacing, lumber sheathing shall have a minimum_Fb_ of 855 and minimum E of 1,700,000 (see ANSI AWC NDS).For SI: 1 inch = 25.4 mm, 1 pound per square inch = 6.895 kPa.
N/A = Not Applicable.
a. For this support spacing, lumber sheathing shall have a minimum_Fb_ of 675 and minimum E of 1,100,000 (see ANSI AWC NDS).
b.CRC § 3.4 High relevance — show source text
The wood structural panel sheathing shall be not less
than7/16 inch in thickness.
b. Spacing of fasteners is per 12 inches of siding width. For other siding widths, multiply “Spacing of Fasteners” above by a factor of 12/s, where “s” is the siding width in inches.
Fastener spacing shall never be greater than the manufacturer’s minimum recommendations.|R703.3.4 Minimum fastener length and penetration. Fasteners shall have the greater of the minimum length specified in Table R703.3(1) or as required to provide a minimum penetration into framing as follows:
Fasteners for horizontal aluminum siding, steel siding, particleboard panel siding, wood structural panel siding in accordance with ANSI/APA-PRP 210, fiber-cement panel siding and fiber-cement lap siding installed over foam plastic sheathing shall penetrate not less than 1 [1] / 2 inches (38 mm) into framing or shall be in accordance with the manufacturer’s installation instructions.
Fasteners for hardboard panel and lap siding shall penetrate not less than 1 [1] / 2 inches (38 mm) into framing.
Fasteners for vinyl siding and insulated vinyl siding shall be installed in accordance with Section R703.11 or R703.13.
Fasteners for polypropylene siding shall be installed in accordance with Section R703.14.
Fasteners for vertical or horizontal wood siding shall penetrate not less than 1 [1] / 2 inches (38 mm) into studs, studs and wood sheathing combined, or blocking.
Fasteners for siding material installed over foam plastic sheathing shall have sufficient length to accommodate foam plastic sheathing thickness and to penetrate framing or sheathing and framing combined, as specified in Items 1 through 5.
R703.4 Flashing. Approved corrosion-resistant flashing shall be applied in a manner to prevent entry of water into the wall cavity or penetration of water to the building structural framing components. Overlapped flashing shall be applied in shingle fashion. Selfadhered membranes used as flashing shall comply with AAMA 711. Fluid-applied membranes used as flashing in exterior walls shall comply with AAMA 714. The flashing shall extend to the surface of the exterior wall finish. Flashing shall be installed above deck ledgers in accordance with Section R507.9.1.5.
Approved corrosion-resistant flashings shall be installed at the following locations:
Exterior window and door openings. Flashing at exterior window and door openings shall be installed in accordance with Section R703.4.1.
At the intersection of chimneys or other masonry construction with frame or stucco walls, with projecting lips on both sides under stucco copings.
Under and at the ends of masonry, wood or metal copings and sills.
Continuously above all projecting wood trim.
Where exterior porches, decks or stairs attach to a wall or floor assembly of wood-frame construction.
At wall and roof intersections.
At built-in gutters.
R703.4.1 Flashing installation at exterior window and door openings. Flashing at exterior window and door openings shall extend to the surface of the exterior wall finish or to a water-resistive barrier complying with Section R703.2 for subsequent drainage. Air sealing shall be installed around all window and door openings on the interior side of the rough opening gap. Mechanically attached flexible flashings shall comply with AAMA 712. Flashing at exterior window and door openings shall be installed in accordance with one or more of the following: 1.
CRC § 25.4 High relevance — show source text
Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
f. Cladding weight is the maximum weight of cladding materials in pounds per square foot of wall area. The 3 psf category typically applies to panel and lap siding materials; the
11 psf category typically applies to conventional three-coat stucco of7/8-inch thickness; and 15 psf to 25 psf categories typically apply to adhered masonry veneers.|For SI: 1 inch = 25.4 mm, 1 pound per square foot = 0.0479 kPa, 1 pound per square inch = 6.895 kPa.
DR = Design Required.
o.c. = On Center.
a. Wood framing shall be Spruce-pine-fir or any wood species with a specific gravity of 0.42 or greater in accordance with AWC NDS.
b. The thickness of wood structural panels complying with the specific gravity requirement of Note a shall be permitted to be included in satisfying the minimum penetration
into framing. For cladding connections to wood structural panels, refer to Table R703.3.3. For brick veneer tie connections to wood structural panels, refer to Table
R703.8.4(2).
c. Nail fasteners shall comply with ASTM F1667, except nail length shall be permitted to exceed ASTM F1667 standard lengths.
d. Fastener vertical spacing is an average spacing associated with the following nail count per foot: 6-inch spacing is associated with two nails per foot, 8-inch spacing is associ-
ated with 1.5 nails per foot, and 12-inch spacing is associated with one nail per foot.
e. Foam sheathing shall have a minimum compressive strength of 15 psi in accordance with ASTM C578 or ASTM C1289.
f. Cladding weight is the maximum weight of cladding materials in pounds per square foot of wall area. The 3 psf category typically applies to panel and lap siding materials; the
11 psf category typically applies to conventional three-coat stucco of7/8-inch thickness; and 15 psf to 25 psf categories typically apply to adhered masonry veneers.|R703.15.2 Furred cladding attachment. Where wood furring is used to attach cladding over foam sheathing, furring minimum fastening requirements to support the cladding weight shall be as specified in Table R703.15.2. Where placed horizontally, wood furring shall be preservative-treated wood in accordance with Section R304.1 or naturally durable wood and fasteners shall be corrosion resistant in accordance Section R304.3.
2025 CALIFORNIA RESIDENTIAL CODE 7-29
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WALL COVERING
TABLE R703.15.2—FURRING MINIMUM FASTENING REQUIREMENTS
FOR APPLICATION OVER FOAM PLASTIC SHEATHING TO SUPPORT CLADDING WEIGHTa, bCol2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 Col10 Col11 Col12 Col13 Col14 Col15 ** FURRING**
MATERIAL** CRC § 0.42 High relevance — show source text
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. Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the
framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.
i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist
to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.|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.CRC § 6.3.1. High relevance — show source text
6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |130|0-60|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |All|> 60|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.|The fastening system shall resist the wind forces in Section 1609.6.3.1.| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 4.882 kg/m2.
a. Minimum fastener size. Corrosion-resistant nails not less than No. 11 gage with5/16-inch head. Fasteners shall be long enough to penetrate into the sheathing3/4 inch or
through the thickness of the sheathing, whichever is less. Attaching wire for clay and concrete tile shall not be smaller than 0.083 inch.
b. Snow areas. Not fewer than two fasteners per tile are required or battens and one fastener.
c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fastened.
d. Horizontal battens. Battens shall be not less than 1 inch by 2 inches nominal. Provisions shall be made for drainage by a riser of not less than1/8 inch at each nail or by 4-foot-
long battens with not less than a1/2-inch separation between battens. Horizontal battens are required for slopes over 7:12.
e. Perimeter fastening areas include three tile courses but not less than 36 inches from either side of hips or ridges and edges of eaves and_gable_ rakes.
f._ Vasd_ shall be determined in accordance with Section 1609.3.1.|For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square foot = 4.882 kg/m2.
a. Minimum fastener size. Corrosion-resistant nails not less than No. 11 gage with5/16-inch head. Fasteners shall be long enough to penetrate into the sheathing3/4 inch or
through the thickness of the sheathing, whichever is less. Attaching wire for clay and concrete tile shall not be smaller than 0.083 inch.
b. Snow areas. Not fewer than two fasteners per tile are required or battens and one fastener.
c. Roof slopes greater than 24:12. The nose of all tiles shall be securely fastened.
d. Horizontal battens. Battens shall be not less than 1 inch by 2 inches nominal. Provisions shall be made for drainage by a riser of not less than1/8 inch at each nail or by 4-foot-
long battens with not less than a1/2-inch separation between battens.CRC § 2306.1 Medium relevance — show source text
For other conditions and panel thickness, space fasteners maximum 12 inches
on center on intermediate supports.
c. 3/8-inch panel thickness or siding with a span rating of 16 inches on center is the minimum recommended where applied directly to framing as exterior siding. For grooved
panel siding, the nominal panel thickness is the thickness of the panel measured at the point of fastening.
d. Framing at adjoining panel edges shall be 3 inches nominal or wider.
e. Values apply to all-veneer plywood. Thickness at point of fastening on panel edges governs shear values.
f. Where panels are applied on both faces of a wall and fastener spacing is less than 6 inches on center on either side, panel joints shall be offset to fall on different framing
members, or framing shall be 3 inches nominal or thicker at adjoining panel edges.
g. In Seismic Design Category D, E or F, where shear design values exceed 350 pounds per linear foot, all framing members receiving edge fastening from abutting panels shall be
not less than a single 3-inch nominal member, or two 2-inch nominal members fastened together in accordance with Section 2306.1 to transfer the design shear value
between framing members. Wood structural panel joint and sill plate nailing shall be staggered at all panel edges. See AWC SDPWS for sill plate size and anchorage
requirements.
h. Staples shall have a minimum crown width of7/16 inch and shall be installed with their crowns parallel to the long dimension of the framing members.
i. For shear loads of normal or permanent load duration as defined by the ANSI/AWC NDS, the values in the table shall be multiplied by 0.63 or 0.56, respectively.|TABLE 2306.3(2)—ALLOWABLE SHEAR VALUES (plf) FOR WIND OR SEISMIC LOADING ON SHEAR WALLS OF
FIBERBOARD SHEATHING BOARD CONSTRUCTION UTILIZING STAPLES FOR TYPE V CONSTRUCTION ONLYa, b, c, d, eCol2 Col3 Col4 Col5 THICKNESS AND GRADE
(inches)STAPLE GAGE AND DIMENSIONS ALLOWABLE SHEAR VALUE (pounds per linear foot)
STAPLE SPACING AT PANEL EDGES (inches)aALLOWABLE SHEAR VALUE (pounds per linear foot)
STAPLE SPACING AT PANEL EDGES (inches)aALLOWABLE SHEAR VALUE (pounds per linear foot)
STAPLE SPACING AT PANEL EDGES (inches)aTHICKNESS AND GRADE
(inches)STAPLE GAGE AND DIMENSIONS 4 3 2 1/2 or25/32 Structural No. 16 gage galvanized staple,
7/16″ crown 13/4 inches long150 200 225 1/2 or25/32 Structural No. 16 gage galvanized staple,
1″ crown 13/4 inches long220 290 325 For SI: 1 inch = 25.4 mm, 1 pound per foot = 14.5939 N/m.
a. Fiberboard sheathing shall not be used to brace concrete or masonry walls.
b.CRC § 0.192 Medium relevance — show source text
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. Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the
framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.
i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist
to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.|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.CRC § 0.192 Medium relevance — show source text
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. Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the
framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.
i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist
to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.|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.CRC § 1.1 High relevance — show source text
For this support spacing, lumber sheathing shall have a minimum_Fb_ of 855 and minimum E of 1,700,000 (see ANSI AWC NDS).|
R503.1.1 End joints. End joints in lumber used as subflooring shall occur over supports unless end-matched lumber is used, in which case each piece shall bear on not less than two joists. Subflooring shall be permitted to be omitted where joist spacing does not exceed 16 inches (406 mm) and a 1-inch (25 mm) nominal tongue-and-groove wood strip flooring is applied perpendicular to the joists.
R503.2 Wood structural panel sheathing.
R503.2.1 Identification and grade. Wood structural panel sheathing used for structural purposes shall conform to CSA O325, CSA O437 DOC PS 1 or DOC PS 2. Panels shall be identified for grade, bond classification and Performance Category by a grade mark or certificate of inspection issued by an approved agency. The Performance Category value shall be used as the “nominal panel thickness” or “panel thickness” wherever referenced in this code.
R503.2.1.1 Subfloor and combined subfloor underlayment. Where used as subflooring or combination subfloor underlayment, wood structural panels shall be of one of the grades specified in Table R503.2.1.1(1). Where sanded plywood is used as combination subfloor underlayment, the grade, bond classification, and Performance Category shall be as specified in Table R503.2.1.1(2).
5-12 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
FLOORS
TABLE R503.2.1.1(1)—ALLOWABLE SPANS AND LOADS FOR WOOD STRUCTURAL
PANELS FOR ROOF AND SUBFLOOR SHEATHING AND COMBINATION SUBFLOOR UNDERLAYMENTa, b, cCol2 Col3 Col4 Col5 Col6 Col7 Col8 Col9 SPAN
RATINGMINIMUM
NOMINAL
PANEL
THICKNESS
(inch)ALLOWABLE LIVE LOAD
(psf)h, IALLOWABLE LIVE LOAD
(psf)h, IMAXIMUM SPAN
(inches)MAXIMUM SPAN
(inches)LOAD
(pounds per square foot,
at maximum span)LOAD
(pounds per square foot,
at maximum span)MAXIMUM SPAN
(inches)SPAN
RATINGMINIMUM
NOMINAL
PANEL
THICKNESS
(inch)Span
@ 16″ o.c.Span
**@ 24″ o.c.CRC § 25.4 Medium relevance — show source text
Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
on roof sheathing panel edges applies to panel edges supported by framing members and required blocking. Blocking of roof or floor sheathing panel edges perpendicular to the
framing members need not be provided except as required by other provisions of this code. Floor perimeter shall be supported by framing members or solid blocking.
i. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule, provide two toe nails on one side of the rafter and toe nails from the ceiling joist
to top plate in accordance with this schedule. The toe nail on the opposite side of the rafter shall not be required.|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. Gypsum sheathing shall conform to ASTM C1396 and shall be installed in accordance with ASTM C1280 or GA 253 . Fiberboard sheathing shall conform to ASTM C208.
h. Spacing of fasteners on floor sheathing panel edges applies to panel edges supported by framing members and required blocking and at floor perimeters only. Spacing of fasteners
on roof sheathing panel edges applies to panel edges supported by framing members and required blocking.CRC § 2-8 Medium relevance — show source text
128″); or
2-8d common (21/2″ × 0.131″); or
2-3″ × 0.131″ nails|Each end, toe nail|Each end, toe nail| |ITEM|DESCRIPTION OF BUILDING ELEMENTS|NUMBER AND TYPE OF FASTENERa, b, c|SPACING OF FASTENERS|SPACING OF FASTENERS| |ITEM|DESCRIPTION OF BUILDING ELEMENTS|NUMBER AND TYPE OF FASTENERa, b, c|Edgesh
(inches)|Intermediate
supportsc, e
(inches)| |Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing
[see Table R602.3(3) for wood structural panel exterior wall sheathing to wall framing]|Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing
[see Table R602.3(3) for wood structural panel exterior wall sheathing to wall framing]|Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing
[see Table R602.3(3) for wood structural panel exterior wall sheathing to wall framing]|Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing
[see Table R602.3(3) for wood structural panel exterior wall sheathing to wall framing]|Wood structural panels, subfloor, roof and interior wall sheathing to framing and particleboard wall sheathing to framing
[see Table R602.3(3) for wood structural panel exterior wall sheathing to wall framing]| |31|3/8″ −1/2″|6d common or deformed
(2″ × 0.113″ × 0.266″ head); or 23/8″ × 0.113″
× 0.266″ head nail (subfloor, wall)i|6|12| |31|3/8″ −1/2″|8d common (21/2″ × 0.131″ × 0.281″ head)
nail (roof); or
RSRS-01 (23/8″ × 0.113″ × 0.281″ head) nail
(roof)b|6f|6f| |32|19/32″ –3/4″|8d common (21/2″ × 0.131″) nail
(subfloor, wall)|6|12| |32|19/32″ –3/4″|8d common (21/2″ × 0.131″ × 0.281″ head)
nail (roof); or
RSRS-01; (23/8″ × 0.113″ × 0.281″ head) nail
(roof)b|6f|6f| |32|19/32″ –3/4″|Deformed 23/8″ × 0.113 × 0.266″ head
(wall or subfloor)|6|12| |33|7/8″ – 11/4″|10d common (3″ × 0.148″) nail; or
(21/2″ × 0.131 × 0.CRC § 0.113 Medium 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 § 0.281 Medium relevance — show source text
131″ ×
0.281″ head) nail (roof); or
RSRS-01 (23/8″ × 0.113″ × 0.281_"_ head)
nail (roof)d|6e|6e| |31.19/32″ –3/4″|23/8″ × 0.113″× 0.266_″_ head nail; or
2″ 16 gage staple,7/16″ crown (subfloor
and wall)|4|8| |32.7/8″ – 11/4″|10d common (3″ × 0.148″); or
deformed (21/2″ × 0.131″ × 0.281_"_ head)|6|12| |Other exterior wall sheathing|Other exterior wall sheathing|Other exterior wall sheathing|Other exterior wall sheathing| |33.1/2″ fiberboard sheathingb|11/2″ × 0.120″, galvanized roofing nail
(7/16″ head diameter); or
11/4″ 16 gage staple with7/16″ or 1″ crown|3|6| |34.25/32″ fiberboard sheathingb|13/4″ × 0.120″ galvanized roofing nail
(7/16″ diameter head); or
11/2″ 16 gage staple with7/16″ or 1″ crown|3|6|23-20 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
WOOD
TABLE 2304.10.2—FASTENING SCHEDULE—continued Col2 Col3 Col4 DESCRIPTION OF BUILDING ELEMENTS NUMBER AND TYPE OF FASTENERg SPACING AND LOCATION SPACING AND LOCATION 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 35.3/4″ and less 8d common (21/2″ × 0.131″); or
deformed (2″ × 0.113″); or
deformed (2_"_ × 0.120_"_)6 12 36.7/8″ – 1″ 8d common (21/2″ × 0.131″); or
deformed (21/2″ × 0.131″); or
deformed (21/2″ × 0.120″)6 12 37. 11/8″ – 11/4″ 10d common (3″ × 0.148″); or
deformed (21/2″ × 0.131″); or
deformed (21/2" × 0.120")6 12 Panel siding to framing Panel siding to framing Panel siding to framing Panel siding to framing 38.1/2″ or less 6d corrosion-resistant siding (17/8″ ×
0.106″); or
6d corrosion-resistant casing (2″ ×
0.099″)6 12 39. CRC § 104.2.3. Medium relevance — show source text
Connections using nails and staples of other materials, such as stainless steel, shall be designed
by acceptable engineering practice or approved under Section 104.2.3.|For SI: 1 inch = 25.4 mm.
a. Nails spaced at 6 inches at intermediate supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer
to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.
b. Spacing shall be 6 inches on center on the edges and 12 inches on center at intermediate supports for nonstructural applications. Panel supports at 16 inches (20 inches if
strength axis in the long direction of the panel, unless otherwise marked).
c. Where a rafter is fastened to an adjacent parallel ceiling joist in accordance with this schedule and the ceiling joist is fastened to the top plate in accordance with this schedule,
the number of toenails in the rafter shall be permitted to be reduced by one nail.
d. RSRS is a Roof Sheathing Ring Shank nail meeting the specifications in ASTM F1667.
e. Tabulated fastener requirements apply where the basic wind speed,V, is less than 140 mph. 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 basic wind speed,V, is greater than 130 mph in Expo-
sure B or greater than 110 mph in Exposure C. Spacing exceeding 6 inches on center at intermediate supports shall be permitted where the fastening is designed per the AWC
NDS. Where the specific gravity of the wood species used for roof framing 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 unless alternative fastening is designed in accordance with AWC NDS. Where the specific gravity of the wood
species used for roof framing is less than 0.35, fastening of the roof sheathing shall be designed in accordance with AWC NDS.
f. Fastening is only permitted where the basic wind speed,V, is less than or equal to 110 mph and where fastening is to wood framing of a species with specific gravity greater
than or equal to 0.42 in accordance with AWC NDS.
g. Nails and staples are carbon steel meeting the specifications of ASTM F1667. Connections using nails and staples of other materials, such as stainless steel, shall be designed
by acceptable engineering practice or approved under Section 104.2.3.|For SI: 1 inch = 25.4 mm.
a. Nails spaced at 6 inches at intermediate supports where spans are 48 inches or more. For nailing of wood structural panel and particleboard diaphragms and shear walls, refer
to Section 2305. Nails for wall sheathing are permitted to be common, box or casing.
b. Spacing shall be 6 inches on center on the edges and 12 inches on center at intermediate supports for nonstructural applications. Panel supports at 16 inches (20 inches if
strength axis in the long direction of the panel, unless otherwise marked).
c.
Frequently asked questions
What is the minimum panel thickness for a 24" o.c. joist spacing?
For lumber sheathing, Table R503.1 lists 11/16" net thickness perpendicular and 3/4" diagonal for 24 in. o.c. joists; consult § R503.1 for the exact table and notes.
Can I use a thinner panel if the manufacturer recommends it?
Only if the panel meets the Code grade/performance and the manufacturer’s span rating corresponds to the required span in Table R503.2.1.1(1). The Code requires panels be identified and used per the listed Performance Category. § R503.2.1
How close must nails be at panel edges?
Common table entries require 6 inches o.c. at panel edges for many panel thicknesses; field (intermediate supports) is commonly 12 inches o.c. — verify the row for your exact panel thickness in the fastening schedule referenced by § R503.
Do panel end joints have to occur over joists?
Yes — panel end joints must be supported by framing members or blocking; end‑matched lumber is the exception where each piece must bear on two joists. § R503.1.1
If I have a 48" panel support spacing, do fastener spacings change?
Yes. For very large spans (e.g., 48 in.), nails at supports are limited to not more than 6 in. o.c. at all supports (table notes). Check the table notes for long‑span requirements and required Fb/E values.
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