California Fire Codes Put Focus on Plastic Decking Concerns

The new codes affect “Fire Hazard Severity Zones,” identified by topography (fire spreads faster on slopes), vegetation that fuels fires, weather patterns, history of past wildfires, and likelihood of fire spreading from neighboring areas. Those zones affect a significant portion of the state, mostly in rural areas, but they also frequently intersect with populated areas. According to Kevin Reinertson at SFM, the standards have been projected to affect 8%–11% of new construction in California.

Landscaping provisions require homeowners to clear flammable materials for 30 feet (9 m) around a building and manage fuel loads for 100 feet (30 m) around a building to create a “defensible space” for firefighters. The standards cover vents, walls, windows, and decking—roofs should be ignition-resistant, and cornice vents that could admit flames are prohibited, for example. Decking has also been a key focus of the regulations. Many homes feature wide expanses of decking, which is usually flammable; laid horizontally with air gaps between boards, the decking can easily catch burning embers and ignite.