California Historical Building Code (CHBC)

The California Historical Building Code (CHBC) is Part 8 of the California Building Standards Code (Title 24, California Code of Regulations), also known as the State Historical Building Code. It provides alternative building regulations for the repair, alteration, rehabilitation, restoration, relocation and continued use of a qualified historical building or property, so that owners can meet fire, life-safety, seismic and accessibility goals without destroying the historic fabric that ordinary code prescriptions would require them to replace.

The 2025 CHBC is the current edition, effective January 1, 2026, replacing the 2022 edition. The code is authorized by California Health and Safety Code Sections 18950–18961 and administered through the Division of the State Architect, but it is permissive, not mandatory — a project elects to use it. Local jurisdictions adopt the statewide edition and may add amendments, and a building must first be a "qualified historical" resource. Determining eligibility and the right alternative is exactly what GoCodebook helps you reconcile.

The CHBC is organized as numbered Sections 8-1xx through 8-10xx rather than chapters, each covering one subject area: application and enforcement (8-1xx), definitions (8-2xx), general provisions (8-3xx), fire and life safety (8-4xx), means of egress (8-5xx), accessibility (8-6xx), structure (8-7xx), archaic materials (8-8xx), building services (8-9xx) and relocation (8-10xx). The section list below opens each one.

The CHBC addresses the same safety subjects as the regular code — use and occupancy, means of egress, fire protection, structural and seismic design, accessibility, and mechanical, plumbing and electrical systems — but supplies alternative provisions tailored to historic construction. Instead of forcing modern prescriptive solutions, it lets a design professional demonstrate equivalent safety while keeping archaic materials and methods such as unreinforced masonry, lath-and-plaster, board sheathing and historic timber framing. The structural provisions live in the CHBC's structural chapter and have been used on URM, steel-and-masonry-infill and timber buildings for seismic strengthening and earthquake-damage repair.

A core concept is the "qualified historical building or property" — generally a building, site, structure, object or district listed or eligible for a national, state or local historic register or inventory. Only qualified resources may use the CHBC. The code is frequently the tool that makes adaptive reuse financially feasible, because it avoids triggering full modern upgrades that would gut a landmark. See where coverage is deepest.

For accessibility, the CHBC allows alternatives where strict application of CBC Chapter 11B would threaten or destroy historic significance — for example, by permitting alternate routes, equivalent facilitation or limited exceptions, while still maximizing access to the greatest extent feasible. This is a careful balance: the goal is meaningful access without erasing the historic character that made the building worth preserving.

For seismic and structural safety, the CHBC provides alternative performance-based regulations that recognize how historic buildings actually behave, rather than imposing new-construction demands. This is especially important for unreinforced masonry retrofit and for re-occupying long-vacant or damaged landmarks. The CHBC commonly works alongside the California Existing Building Code (Part 10), and a design team chooses the pathway that best preserves the resource while delivering equivalent safety.

Using the CHBC is optional and project-specific. An owner or design professional elects it, documents that the building is a qualified historical resource, and then proposes alternatives that the building official — often with input from the State Historical Building Safety Board — reviews for equivalent safety. Because it is discretionary and judgment-based, outcomes vary by jurisdiction and by how well the proposal is justified.

GoCodebook identifies the adopted edition, the relevant CHBC alternative provisions, and any local amendments, then returns the governing language with a citation so you can build a defensible compliance argument. Whether you are restoring a landmark theater, converting a historic warehouse, or seismically strengthening a URM building, the CHBC is usually the difference between a feasible adaptive-reuse project and a teardown.

A building must first be a qualified historical building or property — listed or eligible for a national, state or local historic register, or designated by a local ordinance. Section 8-201 defines the term, and Sections 8-101 to 8-106 cover title, application, organization and enforcement, including the role of the State Historical Building Safety Board in reviewing rulings and appeals.

Once a building qualifies, the CHBC allows alternatives that achieve equivalent safety rather than identical prescriptions. Section 8-105 opens the door to alternative construction methods and materials; Sections 8-402 through 8-412 cover fire-resistive construction, interior finishes, wood lath and plaster, occupancy separation, floor area, vertical shafts, roof covering, alarms, sprinklers and high-rise provisions with historic-appropriate alternatives.

The point is not to relax safety but to reach it a different way — an original wood-lath-and-plaster assembly that cannot be tested to a modern rating can be evaluated on its demonstrated performance, and a monumental stair that cannot meet current riser geometry can be retained where compensating measures are provided.

Egress alternatives are in Sections 8-501 to 8-504, covering general provisions, escape or rescue windows and doors, and railings and guardrails — the last being where original balustrades that do not meet current height or opening limits are addressed.

Accessibility is in Sections 8-601 to 8-604, and the key concept is equivalent facilitation (8-604): providing access in a way that achieves substantially equivalent or greater usability where strict compliance would threaten or destroy the historic character. This is the mechanism behind ramp placement, lift installation and entrance alternatives in historic buildings — it is not a blanket exemption, and it requires documentation.

Structure is Sections 8-701 to 8-706, covering the structural survey, non-historical additions and alterations, structural regulations and lateral-load provisions. Archaic materials — Sections 8-801 to 8-812 — give allowable values for adobe, unreinforced masonry, hollow clay tile, veneers, wood, iron and early concrete that modern material standards simply do not contain.

California's adopted codes — including the California Historical Building Code (CHBC) — are published under Title 24 and hosted on code libraries such as UpCodes (up.codes) and ICC Digital Codes from the International Code Council (ICC). Those let you read the text section by section.

GoCodebook goes further: instead of searching a code library, you ask a question and get the controlling provision for the edition and local amendments your jurisdiction adopted, with a citation to verify. See how GoCodebook compares to UpCodes and ICC.