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Chapter 9 — ROOF ASSEMBLIES

Section R906 — ROOF INSULATION

2025 California Residential Code (Title 24, Part 2.5) · 2025 edition · updated 2026-07-29 · California

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

R906.1 General.

Where above-deck thermal insulation is installed, such insulation shall be covered with an approved roof covering and shall comply with NFPA 276 or UL 1256.

R906.2 Material standards.

Above-deck thermal insulation board shall comply with the standards in Table R906.2.

TABLE R906.2—MATERIAL STANDARDS FOR ROOF INSULATION

MATERIAL STANDARD
Cellular glass board ASTM C552or ASTM C1902
Composite boards ASTM C1289, Type III, IV, V or VI
Expanded polystyrene ASTM C578
Extruded polystyrene board ASTM C578
Fiber-reinforced gypsum board ASTM C1278
Glass-faced gypsum board ASTM C1177
Mineral wool board ASTM C726
Perlite board ASTM C728
Polyisocyanurate board ASTM C1289, Type I or II
Wood fiberboard ASTM C208

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▸ Contents — 2025 California Residential Code (Title 24, Part 2.5)
2025 California Residential Code (Title 24, Part 2.5)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — BUILDING PLANNING
  4. Chapter 4 — FOUNDATIONS
  5. Chapter 5 — FLOORS
  6. Chapter 6 — WALL CONSTRUCTION
  7. Chapter 7 — WALL COVERING
  8. Chapter 8 — ROOF-CEILING CONSTRUCTION
  9. ▸ Chapter 9 — ROOF ASSEMBLIES
    Overview
    1. Section R901 — GENERAL
    2. Section R902 — FIRE CLASSIFICATION
    3. Section R903 — WEATHER PROTECTION
    4. Section R904 — MATERIALS
    5. Section R905 — REQUIREMENTS FOR ROOF COVERINGS
    6. Section R906 — ROOF INSULATION
    7. Section R907 — ROOFTOP-MOUNTED PHOTOVOLTAIC PANEL SYSTEMS
    8. Section R908 — REROOFING
    9. Section R909 — ROOF COATINGS
  10. Chapter 10 — CHIMNEYS AND FIREPLACES
  11. Chapter 44 — REFERENCED STANDARDS
  12. Appendix AA — BOARD OF APPEALS
  13. Appendix AB — PERMIT FEES
  14. Appendix AC — RESERVED
  15. Appendix BA — RESERVED
  16. Appendix BB — TINY HOUSES
  17. Appendix BC — RESERVED
  18. Appendix BD — RESERVED
  19. Appendix BE — RADON CONTROL METHODS
  20. Appendix BF — PATIO COVERS
  21. Appendix BG — SOUND TRANSMISSION
  22. Appendix BH — AUTOMATIC VEHICULAR GATES
  23. Appendix BI — LIGHT STRAW-CLAY CONSTRUCTION
  24. Appendix BJ — STRAWBALE CONSTRUCTION
  25. Appendix BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
  26. Appendix BL — HEMP-LIME (HEMPCRETE) CONSTRUCTION
  27. Appendix BM — 3D-PRINTED BUILDING CONSTRUCTION
  28. Appendix BN — EXTENDED PLATE WALL CONSTRUCTION
  29. Appendix BO — EXISTING BUILDINGS AND STRUCTURES
  30. Appendix CA — RESERVED
  31. Appendix CB — RESERVED
  32. Appendix CC — RESERVED
  33. Appendix CD — RESERVED
  34. Appendix CE — RESERVED
  35. Appendix CF — RESERVED
  36. Appendix CG — NONSEWERED SANITATION SYSTEMS
  37. Appendix CH — PRIVATE SEWAGE DISPOSAL
  38. Appendix CI — SWIMMING POOL SAFETY ACT
  39. Appendix CJ — EMERGENCY HOUSING
  40. Appendix CK — AREAS PROTECTED BY THE FACILITIES OF THE CENTRAL…

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