On Thursday, April 23, 2026, California's updated Wildland-Urban Interface (WUI) Building Code — Title 24, Part 7 — took effect statewide. It's the most significant restructuring of California's wildfire-construction standards in years. Every home in Lamorinda sits in a Fire Hazard Severity Zone, so for our area, "statewide WUI code" means "the code that applies to your house."
If you're planning a roof, vent, deck, or remodel project this summer, you're now building under the 2026 code. Here's what that actually means.
What Changed at the State Level
The 2026 code consolidates and tightens what the 2019 and earlier code cycles had built up across California Building Code Chapter 7A (single-family structures in WUI), California Residential Code R337 (the residential equivalent), and the standalone California WUI Code. The major moves:
- Tighter ignition-resistance standards for exterior wall coverings, soffits, and under-floor enclosures in the WUI.
- Stricter vent specifications — the OSFM Building Materials Listing Category 8165 is now the default reference for compliant ember-resistant vents.
- Updated roof, deck, and exterior-glazing requirements to reflect what the 2017–2025 California fire seasons taught the code-writers about ember intrusion.
- Stronger alignment with defensible-space requirements in PRC 4291 — the construction-side and the vegetation-side of fire-hardening are now expected to work together, not in separate silos.
This isn't a list of new ideas. The materials, methods, and clearances in the code are the same things home-hardening practitioners (and IBHS, and CAL FIRE, and your insurance carrier) have been recommending for years. What changed is which of those recommendations are now requirements.
How This Stacks with MOFD's Local Ordinances
Lamorinda has two layers of code on top of the state code:
- MOFD Ordinance 26-01 (Fire Code) and MOFD Ordinance 26-02 (WUI Code) — ratified by Moraga (Feb 11) and Orinda (March 3) earlier this year. These add local amendments that are more restrictive than state minimums where MOFD's board determined the topography, climate, and fuel load warranted it.
- The 2026 California WUI Code — now the state baseline both ordinances build on top of.
If you're in Moraga or Orinda, your project has to clear the stricter of the two. Lafayette is served by ConFire, not MOFD — so 26-01 and 26-02 don't apply to Lafayette homeowners, but the 2026 statewide WUI code does.
For more on what MOFD's local ordinances actually require, see our breakdown of Ordinances 26-01 and 26-02.
What Triggers Code Compliance
Not every weekend project pulls a permit, but a lot of fire-relevant work does. As a rule of thumb, code applies when you:
- Build, add to, or substantially remodel a structure
- Replace a roof (most jurisdictions trigger compliance once you hit a percentage of the roof area)
- Replace siding, eaves, or soffits in a way that exposes the underlying assembly
- Replace or significantly modify decks and exterior stairways
- Replace exterior windows or glazing in a way that requires re-flashing
- Replace vents in walls, eaves, or under-floor crawl spaces
Maintenance and like-for-like repairs generally don't trigger compliance, but the line between "repair" and "replace" matters — and it's where most homeowner confusion lives. When in doubt, call MOFD or your city's building department before you start.
A Word on Selling Your Home
You'll see headlines this summer about defensible-space inspections at the time of sale. To be clear about what that is:
AB 38 has been California law since 2021. It requires sellers of homes in High and Very High Fire Hazard Severity Zones — which includes most of Lamorinda — to provide compliant defensible-space documentation as part of the transaction. This isn't a brand-new July 2026 requirement; it's been in effect for years.
What is true: as the 2026 code rolls out and the state ramps up enforcement, inspectors are getting busier. If you're listing your home this summer or fall, schedule the inspection now — not in August when every seller in Contra Costa County is calling the same handful of certified inspectors.
Don't Wait for the Code to Make You Do It
Here's the thing about codes: they're a floor, not a ceiling. They tell you what you have to do if you pull a permit. They don't help you between permits — and most fire-hardening work that protects your house doesn't require a permit at all.
A clean five-foot zone, screened vents, gutter guards, a chipped brush pile, and a separation between your fence and your house don't need a building inspector to bless them. They just work. The 2026 code is good news because it raises the floor for the work that does require permits — but the most important work in front of you this fire season is the work you can start tomorrow morning without filing a single piece of paper.
If you live in MOFD territory, the district is currently giving away gutter guards, vent mesh, and chipping services through June 30, 2026 — see our free MOFD programs guide.
If you want a step-by-step on the highest-leverage projects, our home hardening checklist walks through the room-by-room sequence.
The code validates common sense. It doesn't create it. Don't wait.
Continue Learning
- The Big Three: Roof, Vents & Defensible Space — the highest-leverage projects, code or no code
- Defensible Space Zones: 0-1-2 — the vegetation half of the code's expectations
- Class A Roof Replacement — what the code now requires for re-roofs
- Noncombustible Siding, Enclosed Eaves & Soffits, Multi-Pane Windows Upgrade — the project-specific deep dives for the assemblies the code most often touches
- What MOFD's Local Ordinances 26-01 and 26-02 Require — the local layer that stacks on the state code
Sources: 2025 California WUI Code (effective April 23, 2026) | California Public Resources Code 4291 (defensible space) | MOFD Ordinances 26-01 and 26-02 — our breakdown