California Building Standards Code: Administration, Occupancy, Construction Types, and Permits
One code, many parts
Title 24 is the California Building Standards Code, published in parts. Part 1 is the California Administrative Code, Part 2 the CBC, Part 2.5 the CRC, Part 6 Energy, Part 9 Fire, and Part 11 CALGreen. The CBC adopts the IBC with California amendments, so a question may test the national base text, the amendment, or both.
Occupancy and type
Every project starts with occupancy classification (A, B, E, F, H, I, M, R, S, U, plus accessory and incidental uses under CBC 508 and 509) and construction type (IA through VB; Type IV now includes IV-A, IV-B, and IV-C mass timber). Those two decisions drive allowable height and area (Tables 503, 504, 506.2), fire-resistance, egress, and detailing. Height and area can be increased by frontage and by sprinklers.
Permits and administration
CBC Chapter 1 covers permits, plan review, deferred submittals, inspections, and certificates of occupancy. Work requiring a permit, deferred submittals, and permit expiration (generally commencement within 12 months and no suspension of work for 180 days, subject to local amendment) are frequent test items. Local amendments must be more restrictive and must be filed with the Building Standards Commission.
Traps
Confusing part numbers; treating a mixed occupancy as separated when it is not; forgetting that sprinkler and frontage increases are separate multipliers; assuming plan-check approval equals a permit.
Worked example
Type V-B, Group B, one story, fully sprinklered, no frontage: base At = 6,000 sf. Is = 3 for a one-story sprinklered building, so Aa = 6,000 + 3(6,000) = 24,000 sf. For a two-story version, Is = 2, giving 18,000 sf per story with a total-building cap.