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Chapter 8 — ROOF-CEILING CONSTRUCTION

Section R803

California Residential Code (Title 24, Part 2.5) · 2022 edition · updated 2026-09-12 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

R803.1 Lumber sheathing.

Allowable spans for lumber used as roof sheathing shall conform to Table R803.1. Spaced lumber sheathing for wood shingle and shake roofing shall conform to the requirements of Sections R905.7 and R905.8. Spaced lumber sheathing is not allowed in Seismic Design Category D2.

TABLE R803.1 MINIMUM THICKNESS OF LUMBER ROOF SHEATHING

RAFTER OR BEAM SPACING
(inches)		 MINIMUM NET THICKNESS (inches)
24 5/8
48a 11/2 T & G
60b 60b
72c 72c

For SI: 1 inch = 25.4 mm. a. Minimum 270 Fb, 340,000 E. b. Minimum 420 Fb, 660,000 E. c. Minimum 600 Fb, 1,150,000 E.

R803.2 Wood structural panel sheathing.

R803.2.1 Identification and grade. Wood structural panels shall conform to DOC PS 1, DOC PS 2, CSA O325 or CSA O437, and shall be identified for grade, bond classification and performance category by a grade mark or certificate of inspection issued by an approved agency. Wood structural panels shall comply with the grades specified in Table R503.2.1.1(1).

R803.2.1.1 Exposure durability. Wood structural panels, when designed to be permanently exposed in outdoor applications, shall be of an exterior exposure durability. Wood structural panel roof sheathing exposed to the underside shall be permitted to be of interior type bonded with exterior glue, identified as Exposure 1.

R803.2.1.2 Fire-retardant-treated plywood. The allowable unit stresses for fire-retardant-treated plywood, including fastener values, shall be developed from an approved method of investigation that considers the effects of anticipated temperature and humidity to which the fire-retardant-treated plywood will be subjected, the type of treatment and redrying process. The fire-retardant-treated plywood shall be graded by an approved agency.

R803.2.2 Allowable spans. The maximum allowable spans for wood structural panel roof sheathing shall not exceed the values set forth in Table R503.2.1.1(1) or APA E30.

R803.2.3 Installation. Wood structural panel used as roof sheathing shall be installed with joints staggered or not staggered in accordance with Table R602.3(1), APA E30 for wood roof framing or with Table R804.3 for cold-formed steel roof framing. Wood structural panel roof sheathing in

accordance with Table R503.2.1.1(1) shall not cantilever more than 9 inches (229 mm) beyond the gable endwall unless supported by gable overhang framing.

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▸Contents — California Residential Code (Title 24, Part 2.5)
California Residential Code (Title 24, Part 2.5)
  1. Chapter 2 — DEFINITIONS AND ABBREVIATIONS
  2. Appendix AF — RADON CONTROL
  3. Appendix AI — PRIVATE SEWAGE
  4. Appendix AJ — EXISTING
  5. Appendix AK — SOUND
  6. Appendix AO — AUTOMATIC
  7. Appendix AR — LIGHT STRAW-CLAY
  8. Appendix AS — STRAWBALE
  9. Appendix AU — COB CONSTRUCTION
  10. Appendix AV — BOARD
  11. Appendix AW — 3D-PRINTED BUILDING
  12. Chapter 1 — SCOPE AND APPLICATION
  13. Chapter 3 — BUILDING PLANNING
  14. Chapter 4 — FOUNDATIONS
  15. Chapter 5 — FLOORS
  16. Chapter 6 — WALL CONSTRUCTION
  17. Chapter 7 — WALL COVERING
  18. ▸Chapter 8 — ROOF-CEILING CONSTRUCTION
    Overview
    1. Section R801
    2. Section R802
    3. Section R803
    4. Section R804
    5. Section R805
    6. Section R806
    7. Section R807
  19. Chapter 9 — ROOF ASSEMBLIES
  20. Chapter 10 — CHIMNEYS AND FIREPLACES
  21. Chapter 44 — REFERENCED STANDARDS
  22. Appendix AH — PATIO COVERS
  23. Appendix AL — PERMIT FEES
  24. Appendix AQ — TINY HOUSES
  25. Appendix AT — SOLAR-READY PROVISIONS—DETACHED ONE- AND
  26. Appendix AX — SWIMMING POOL SAFETY ACT
  27. Appendix AY — AREAS PROTECTED BY THE FACILITIES
  28. Appendix AZ — EMERGENCY HOUSING

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