Wildfire Building Guide · Marin County

Fire-Resistant Remodeling Guide for Marin County Wildfire Zones

By Solid Bay Construction SF | Updated 2026

Following the devastating North Bay fires, Marin County significantly tightened renovation requirements in its Wildland-Urban Interface (WUI) zones. If your property falls within one, several types of renovation now trigger fire-resistant construction requirements.

What Fire-Resistant Construction Requires

• Class A fire-rated roofing — the highest fire-resistance rating available for roof coverings
• Ember-resistant vents — attic and foundation vents designed to block wind-driven embers from entering the structure, the leading cause of home ignition in wildfires
• Non-combustible siding within 5 feet of the structure
• Multi-pane tempered glass windows — standard single-pane glass can fail under radiant heat well before flames reach the structure
• Non-combustible decking within 10 feet of the structure

Which Renovations Trigger These Requirements

Roof replacement, siding replacement, window replacement, and deck rebuilding in a WUI zone typically trigger the corresponding fire-resistant requirement even if the rest of the renovation is purely cosmetic — so a homeowner replacing an old wood deck, for example, needs to plan for non-combustible decking materials as part of that project, not as a separate future upgrade.

Recommended Materials

For fire zone decking projects, we specify composite decking systems such as Trex Transcend and TimberTech AZEK, which meet non-combustibility requirements while still giving homeowners a natural-wood appearance. For siding, fiber cement and stucco are common non-combustible choices that fit Marin's design aesthetic.

Beyond Code Minimums: Defensible Space

Building code covers the structure itself, but overall wildfire risk also depends on defensible space — vegetation management and clearance around the home. While that's typically a separate landscaping consideration from a construction project, it's worth planning alongside any renovation in a WUI zone rather than treating the two separately.