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Chapter 3 — BUILDING PLANNING

Section R317

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.

PROTECTION OF WOOD AND WOOD-BASED PRODUCTS AGAINST DECAY

R317.1 Location required.

Protection of wood and woodbased products from decay shall be provided in the following locations by the use of naturally durable wood or wood that is preservative-treated in accordance with AWPA U1.

  1. In crawl spaces or unexcavated areas located within the periphery of the building foundation, wood joists or the bottom of a wood structural floor where closer than 18

inches (457 mm) to exposed ground, wood girders where closer than 12 inches (305 mm) to exposed ground, and wood columns where closer than 8 inches (204 mm) to exposed ground.

  1. Wood framing members, including columns, that rest directly on concrete or masonry exterior foundation walls and are less than 8 inches (203 mm) from the exposed ground.

  2. Sills and sleepers on a concrete or masonry slab that is in direct contact with the ground unless separated from such slab by an impervious moisture barrier.

  3. The ends of wood girders entering exterior masonry or concrete walls having clearances of less than 1 /2 inch (12.7 mm) on tops, sides and ends.

  4. Wood siding, sheathing and wall framing on the exterior of a building having a clearance of less than 6 inches (152 mm) from the ground or less than 2 inches (51 mm) measured vertically from concrete steps, porch slabs, patio slabs and similar horizontal surfaces exposed to the weather.

  5. Wood structural members supporting moisture-permeable floors or roofs that are exposed to the weather, such as concrete or masonry slabs, unless separated from such floors or roofs by an impervious moisture barrier. The impervious moisture barrier system protecting the structure supporting floors shall provide positive drainage of water that infiltrates the moisture-perme- able floor topping.

  6. Wood furring strips or other wood framing members attached directly to the interior of exterior masonry walls or concrete walls below grade except where an approved vapor retarder is applied between the wall and the furring strips or framing members.

  7. Portions of wood structural members that form the structural supports of buildings, balconies, porches or similar permanent building appurtenances where those members are exposed to the weather without adequate protection from a roof, eave, overhang or other covering that would prevent moisture or water accumulation on the surface or at joints between members.

Exception: Sawn lumber used in buildings located in a geographical region where experience has demonstrated that climatic conditions preclude the need to use naturally durable or preservative-treated wood where the structure is exposed to the weather.

  1. Wood columns in contact with basement floor slabs unless supported by concrete piers or metal pedestals projecting not less than 1 inch (25 mm) above the concrete floor and separated from the concrete pier by an impervious moisture barrier.

R317.1.1 Field treatment. Field-cut ends, notches and drilled holes of preservative-treated wood shall be treated in the field in accordance with AWPA M4.

R317.1.2 Ground contact. All wood in contact with the ground, embedded in concrete in direct contact with the ground or embedded in concrete exposed to the weather

3-78 2022 CALIFORNIA RESIDENTIAL CODE

Copyright © 2022 by, or licensed to, International Code Council, Inc. (ALL RIGHTS RESERVED); licensed to California Building Standards Commission pursuant to License Agreement. No further reproductions is authorized. Any unauthorized reproduction or distribution is a violation of the federal copyright act and the license agreement, and subject to civil and criminal penalties thereunder.

BUILDING PLANNING

wood shall be in accordance with the connector manufacturer’s recommendations. In the absence of manufacturer’s recommendations, not less than ASTM A653 type G185 zinc-coated galvanized steel, or equivalent, shall be used.

Exceptions:

  1. 1 /2-inch-diameter (12.7 mm) or greater steel bolts.

  2. Fasteners other than nails, staples and timber rivets shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B695, Class 55 minimum.

  3. Plain carbon steel fasteners in SBX/DOT and zinc borate preservative-treated wood in an interior, dry environment shall be permitted.

R317.3.2 Fastenings for wood foundations. Fastenings, including nuts and washers, for wood foundations shall be as required in AWC PWF.

R317.3.3 Fasteners for fire-retardant-treated wood used in exterior applications or wet or damp locations. Fasteners, including nuts and washers, for fire-retardanttreated wood used in exterior applications or wet or damp locations shall be of hot-dipped, zinc-coated galvanized steel, stainless steel, silicon bronze or copper. Fasteners other than nails, staples and timber rivets shall be permitted to be of mechanically deposited zinc-coated steel with coating weights in accordance with ASTM B695, Class 55 minimum.

R317.3.4 Fasteners for fire-retardant-treated wood used in interior applications. Fasteners, including nuts and washers, for fire-retardant-treated wood used in interior locations shall be in accordance with the manufacturer’s recommendations. In the absence of the manufacturer’s recommendations, Section R317.3.3 shall apply.

R317.4 Plastic composites.

Plastic composite exterior deck boards, stair treads, guards and handrails containing wood, cellulosic or other biodegradable materials shall comply with the requirements of Section R507.2.2.

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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
    Overview
    1. Section R300
    2. Section R301
    3. Section R302
    4. Section R303
    5. Section R304
    6. Section R305
    7. Section R307
    8. Section R308
    9. Section R306
    10. Section R309
    11. Section R310
    12. Section R311
    13. Section R312
    14. Section R313
    15. Section R314
    16. Section R315
    17. Section R316
    18. Section R317
    19. Section R318
    20. Section R319
    21. Section R320
    22. Section R321
    23. Section R322
    24. Section R323
    25. Section R324
    26. Section R325
    27. Section R327
    28. Section R326
    29. Section R328
    30. Section R329
    31. Section R330
    32. Section R334
    33. Section R335
    34. Section R336
    35. Section R337
    36. Section R337.1
    37. Section R337.2
    38. Section R337.3
    39. Section R337.4
    40. Section R337.5
    41. Section R337.6
    42. Section R337.7
    43. Section R337.8
    44. Section R337.9
    45. Section R337.10
    46. Section R338
    47. Section R340
  14. Chapter 4 — FOUNDATIONS
  15. Chapter 5 — FLOORS
  16. Chapter 6 — WALL CONSTRUCTION
  17. Chapter 7 — WALL COVERING
  18. Chapter 8 — ROOF-CEILING CONSTRUCTION
  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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