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Appendix AT — SOLAR-READY PROVISIONS—DETACHED ONE- AND

Section AT103 — (RB103)

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.

AT103.1 (RB103.2) General.

New detached one- and twofamily dwellings, and townhouses with not less than 600

square feet (55.74 m 2 ) of roof area oriented between 110 degrees and 270 degrees of true north, shall comply with Sections AT103.2 through AT103.10.

Exceptions:

  1. New residential buildings with a permanently installed on-site renewable energy system.

  2. A building where all areas of the roof that would otherwise meet the requirements of Section AT103 are in full or partial shade for more than 70 percent of daylight hours annually.

AT103.2 (RB103.2) Construction document require-ments for solar-ready zone.

ments for solar-ready zone. Construction documents shall indicate the solar-ready zone.

AT103.3 (RB103.3) Solar-ready zone area.

The total solarready zone area shall be not less than 300 square feet (27.87 m 2 ) exclusive of mandatory access or setback areas as required by the California Fire Code . New townhouses three stories or less in height above grade plane and with a total floor area less than or equal to 2,000 square feet (185.8 m 2 ) per dwelling shall have a solar-ready zone area of not less

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.

APPENDIX AT—SOLAR-READY PROVISIONS—DETACHED ONE- AND TWO-FAMILY DWELLINGS AND TOWNHOUSES

than 150 square feet (13.94 m 2 ). The solar-ready zone shall be composed of areas not less than 5 feet (1524 mm) in width and not less than 80 square feet (7.44 m 2 ) exclusive of access or set-back areas as required by the California Fire Code .

AT103.4 (RB103.4) Obstructions.

Solar-ready zones shall be free from obstructions, including but not limited to vents, chimneys, and roof-mounted equipment.

AT103.5 (RB103.5) Shading.

The solar-ready zone shall be set back from any existing or new, permanently affixed object on the building or site that is located south, east or west of the solar zone a distance not less than two times the object’s height above the nearest point on the roof surface. Such objects include, but are not limited to, taller portions of the building itself, parapets, chimneys, antennas, signage, rooftop equipment, trees and roof plantings.

AT103.6 (RB103.6) Capped roof penetration sleeve.

A capped roof penetration sleeve shall be provided adjacent to a solar-ready zone located on a roof slope of not greater than 1 unit vertical in 12 units horizontal (8-percent slope). The capped roof penetration sleeve shall be sized to accommodate the future photovoltaic system conduit, but shall have an inside diameter of not less than 1 1 /4 inches (32 mm).

AT103.7 (RB103.7) Roof load documentation.

The structural design loads for roof dead load and roof live load shall be clearly indicated on the construction documents.

AT103.8 (RB103.8) Interconnection pathway.

Construction documents shall indicate pathways for routing of conduit or plumbing from the solar-ready zone to the electrical service panel or service hot water system.

AT103.9 (RB103.9) Electrical service reserved space.

The main electrical service panel shall have a reserved space to allow installation of a dual pole circuit breaker for future solar electric installation and shall be labeled “For Future Solar Electric.” The reserved space shall be positioned at the opposite (load) end from the input feeder location or main circuit location.

AT103.10 (RB103.10) Construction documentation certif-icate.

icate. A permanent certificate, indicating the solar-ready zone and other requirements of this section, shall be posted near the electrical distribution panel, water heater or other conspicuous location by the builder or registered design professional.

APPENDIX AT-2 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.

CALIFORNIA RESIDENTIAL CODE – MATRIX ADOPTION TABLE

APPENDIX AU – COB CONSTRUCTION (MONOLITHIC ADOBE)

(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user.

See Chapter 1 for state agency authority and building applications.)

APPENDIX AU

COB CONSTRUCTION (MONOLITHIC ADOBE)

The provisions contained in this appendix are not mandatory unless specifically adopted by a state agency or referenced in the adopting ordinance.

User note:

About this appendix: Cob construction has been used for thousands of years around the world, notably in England and Northern Europe, the Middle East, West Africa, China and the Southwestern United States. An estimated 20,000 cob homes are still inhabited in the English county of Devon alone, some dating from the 15th century. The term “cob” derives from an Old English word for “lump,” since historical structures were often constructed one handful at a time.

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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
  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
    Overview
    1. Section AT101 — (RB101)
    2. Section AT102 — (RB102)
    3. Section AT103 — (RB103)
    4. Section AU101
    5. Section AU102
    6. Section AU103
    7. Section AU104
    8. Section AU105
    9. Section AU106
    10. Section AU107
    11. Section AU108
    12. Section AU109
    13. Section AU110
    14. Section AV101
    15. Section AW101
    16. Section AW102
    17. Section AW103
    18. Section AW104
    19. Section AW105
    20. Section AW106
  26. Appendix AX — SWIMMING POOL SAFETY ACT
  27. Appendix AY — AREAS PROTECTED BY THE FACILITIES
  28. Appendix AZ — EMERGENCY HOUSING

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