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Chapter 9 — ROOF ASSEMBLIES

Section R903 — WEATHER PROTECTION

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.

R903.1 General.

Roof decks shall be covered with approved roof coverings secured to the building or structure in accordance with the provisions of this chapter. Roof assemblies shall be designed and installed in accordance with this code and the approved manufacturer’s instructions such that the roof assembly shall serve to protect the building or structure.

R903.2 Flashing.

Flashings shall be installed in a manner that prevents moisture from entering the wall and roof through joints in copings, through moisture permeable materials and at intersections with parapet walls and other penetrations through the roof plane.

R903.2.1 Locations. Flashings shall be installed at wall and roof intersections, wherever there is a change in roof slope or direction and around roof openings. A flashing shall be installed to divert the water away from where the eave of a sloped roof intersects a vertical sidewall. Where flashing is of metal, the metal shall be corrosion resistant with a thickness of not less than 0.019 inch (0.5 mm) (No. 26 galvanized sheet).

R903.2.2 Crickets and saddles. A cricket or saddle shall be installed on the ridge side of any chimney or penetration more than 30 inches (762 mm) wide as measured perpendicular to the slope. Cricket or saddle coverings shall be sheet metal or of the same material as the roof covering.

Exception: Unit skylights installed in accordance with Section R324.6 and flashed in accordance with the manufacturer’s instructions shall be permitted to be installed without a cricket or saddle.

R903.3 Coping.

Parapet walls shall be properly coped with noncombustible, weatherproof materials of a width not less than the thickness of the parapet wall.

R903.4 Roof drainage.

Unless roofs are sloped to drain over roof edges, roof drains shall be installed at each low point of the roof.

R903.4.1 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary emergency overflow roof drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary drains allow buildup for any reason. Overflow drains having the same size as the roof drains shall be installed with the inlet flow line located 2 inches (51 mm) above the low point of the roof, or overflow scuppers having three times the size of the roof drains and having a minimum opening height of 4 inches (102 mm) shall be installed in the adjacent parapet walls with the inlet flow located 2 inches (51 mm) above the low point of the roof served. The installation and sizing of overflow drains, leaders and conductors shall comply with the California Plumbing Code .

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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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