Fire-Zone Decking

What changed in January 2026

California consolidated its wildfire-zone construction rules into the California Wildland-Urban Interface Code — Title 24, Part 7. It was published on 1 July 2025 and took effect 1 January 2026.

It did not amend the old rules. It replaced them. Chapter 7A was deleted from the California Building Code and Section R337 was repealed from the California Residential Code, and both were relocated into Chapter 5 of the new code, along with Chapter 49 of the Fire Code and the state's defensible-space provisions. Requirements were substantially carried over, but everything was renumbered and reorganised. Appendix H, Section H107 of the new code is a cross-reference tool that maps the old citations to the new ones.

Practically: any plan, proposal or website still citing "CBC Chapter 7A," "709A" or "CRC R337.9.3" as current law is quoting a code book that was superseded eight months ago.

What the code actually regulates on a deck

The walking surface — deck boards and stair treads. Not the framing underneath.

Deck walking surfaces are now governed by Section 504.7.3.2 of the Wildland-Urban Interface Code, which gives several compliance paths. The two that matter in practice for residential work are material meeting SFM Standard 12-7A-4, and material meeting SFM Standard 12-7A-4A where the adjacent exterior wall covering is noncombustible or ignition-resistant. There are also paths through ASTM E2632 and E2726 testing, through approved ignition-resistant material, and through noncombustible material.

Section 504.7.3.1 requires flashing at deck-to-wall intersections — a minimum of six inches of metal flashing.

Why "Class A" on a brochure is not the test

This is the trap, and it catches homeowners and contractors equally.

The relevant test is not a flame-spread number. SFM Standard 12-7A-4 puts burning embers on the deck surface and measures what happens. Embers are what actually take decks in a wildfire — not a flame front travelling across the boards. Several decking products validly listed by the State Fire Marshal were never given the Class A flame-spread test at all, because it is not the compliance path.

Two more distinctions worth holding onto. A Class A roof classification (ASTM E108 or UL 790) is not a one-hour fire-resistance rating (ASTM E119) — they are different tests measuring different things, and the two get blurred constantly in marketing. And the code section sets performance and test requirements; the practical requirement that a product be listed comes from the Health and Safety Code and the State Fire Marshal's Building Materials Listing programme that implements it. Plan check wants to see a listing number.

How to check a product yourself

The Office of the State Fire Marshal maintains a searchable Building Materials Listing database at calfire.govmotus.org. Search the specific product, not the brand. Listings are product-line specific and some carry conditions — most commonly a requirement that the adjacent wall covering be noncombustible or ignition-resistant.

Be aware that the State Fire Marshal's own handbook and several state agency pages still describe listings as complying with "Chapter 7A" and "R337." That is agency paperwork lagging the code change, not evidence that the old chapters survived.

Two things happening right now

Los Angeles has extended the Class A roof-assembly requirement to both High and Very High fire hazard severity zones, not Very High alone. If you have been working from the assumption that a High zone is less restrictive, check again.

Separately, the Board of Forestry approved the Zone 0 ember-resistant zone regulations in August 2026 — the rules about clearing combustible material within five feet of a structure, including within five feet of attached decks. As of this writing they are still going through the Office of Administrative Law and no effective date has been set. Nobody is required to comply yet. New construction will have to on approval, and existing structures phase in over several years after that. Treat anyone selling you Zone 0 compliance today as selling you something that is not yet law.

There is also a further reorganisation of Chapter 5 in the 2025 intervening code cycle, with supplements effective 1 July 2027. Nothing from it is in force now.

What we do about it

We check the specific product against the current State Fire Marshal listing before it goes on a material schedule, and we read the conditions attached to the listing rather than stopping at the word "listed." If you are managing a rebuild and need someone who can read a fire-zone material schedule, that is the work.

Call (818) 345-2866.