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Appendix BB — TINY HOUSES

Section BB104 — LOFTS

2025 California Residential Code (Title 24, Part 2.5) · 2025 edition · updated 2026-07-27 · California

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

BB104.1 Minimum loft area and dimensions.

Lofts used as a sleeping or living space shall meet the minimum area and dimension requirements of Sections BB104.1.1 through BB104.1.3. BB104.1.1 Minimum area. Lofts shall have a floor area of not less than 35 square feet (3.25 m [2] ).

BB104.1.2 Minimum horizontal dimensions. Lofts shall be not less than 5 feet (1524 mm) in any horizontal dimension.

BB104.1.3 Height effect on loft area. Portions of a loft with a sloped ceiling measuring less than 3 feet (914 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required area for the loft. See Figure BB104.1.3. Exception: Under gable roofs with a minimum slope of 6 units vertical in 12 units horizontal (50-percent slope), portions of a loft with a sloped ceiling measuring less than 16 inches (406 mm) from the finished floor to the finished ceiling shall not be considered as contributing to the minimum required area for the loft.

FIGURE BB104.1.3—HEIGHT EFFECT ON LOFT AREA

For SI: 1 foot = 304.8 mm.

BB104.2 Loft access and egress.

The access to and primary egress from lofts shall be of any type described in Sections BB104.2.1 through BB104.2.5. The loft access and egress element along its required minimum width shall meet the loft where its ceiling height is not less than 3 feet (914 mm).

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

APPENDIX BB—TINY HOUSES

BB104.2.1 Stairways. Stairways accessing lofts shall comply with this code or with Sections BB104.2.1.1 through BB104.2.1.7.

BB104.2.1.1 Width. Stairways accessing a loft shall not be less than 17 inches (432 mm) in clear width at or above the handrail. The width below the handrail shall be not less than 20 inches (508 mm).

BB104.2.1.2 Headroom. The headroom above stairways accessing a loft shall be not less than 6 feet 2 inches (1880 mm), as measured vertically, from a sloped line connecting the tread, landing or landing platform nosings in the center of their width and vertically from the landing platform along the center of its width.

BB104.2.1.3 Treads and risers. Risers for stairs accessing a loft shall be not less than 7 inches (178 mm) and not more than 12 inches (305 mm) in height. Tread depth and riser height shall be calculated in accordance with one of the following formulas:

  1. The tread depth shall be 20 inches (508 mm) minus four-thirds of the riser height.
  2. The riser height shall be 15 inches (381 mm) minus three-fourths of the tread depth.

BB104.2.1.4 Landings. Intermediate landings and landings at the bottom of stairways shall comply with Section R318.7.6, except that the depth in the direction of travel shall be not less than 24 inches (610 mm).

BB104.2.1.5 Landing platforms. The top tread and riser of stairways accessing lofts shall be constructed as a landing platform where the loft ceiling height is less than 6 feet 2 inches (1880 mm) where the stairway meets the loft. The landing platform shall be not less than 20 inches (508 mm) in width and in depth measured horizontally from and perpendicular to the nosing of the landing platform. The landing platform riser height to the loft floor shall be not less than 16 inches (406 mm) and not greater than 18 inches (457 mm).

BB104.2.1.6 Handrails. Handrails shall comply with Section R318.7.8.

BB104.2.1.7 Stairway guards. Guards at open sides of stairways, landings and landing platforms shall comply with Section R321.1.

BB104.2.2 Ladders. Ladders accessing lofts shall comply with Sections BB104.2.1 and BB104.2.2.2.

BB104.2.2.1 Size and capacity. Ladders accessing lofts shall have a rung width of not less than 12 inches (305 mm), and 10inch (254 mm) to 14-inch (356 mm) spacing between rungs. Ladders shall be capable of supporting a 300-pound (136 kg) load on any rung. Rung spacing shall be uniform within [3] / 8 inch (9.5 mm).

BB104.2.2.2 Incline. Ladders shall be installed at 70 to 80 degrees from horizontal.

BB104.2.3 Alternating tread devices. Alternating tread devices accessing lofts shall comply with Sections R318.7.12.1 and R318.7.12.2. The clear width at and below the handrails shall be not less than 20 inches (508 mm).

BB104.2.4 Ship’s ladders. Ship’s ladders accessing lofts shall comply with Sections R318.7.13.1 and R318.7.13.2. The clear width at and below handrails shall be not less than 20 inches (508 mm).

BB104.2.5 Loft guards. Loft guards shall be located along the open sides of lofts. Loft guards shall be not less than 36 inches (914 mm) in height or one-half of the clear height to the ceiling, whichever is less. Loft guards shall comply with Section R321.1.3 and Table R301.5 for their components.

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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
  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
    Overview
    1. Section BB101 — GENERAL
    2. Section BB102 — DEFINITIONS
    3. Section BB103 — CEILING HEIGHT
    4. Section BB104 — LOFTS
    5. Section BB105 — EMERGENCY ESCAPE AND RESCUE OPENINGS
  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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