Ember-resistant vents: a 1/8-inch fix that saves homes

Standard attic, crawlspace, and dryer vents are designed for airflow, not ember resistance. Older vents typically use 1/4-inch mesh — large enough for embers and burning debris to pass through into your attic or crawlspace.

Once embers are inside, they land on insulation, stored boxes, or framing, and the home burns from the inside out. Firefighters often arrive to find an undamaged exterior and an attic already in flames.

California Building Code Chapter 7A requires vents in wildland-urban interface areas to either resist ember intrusion or use 1/8-inch noncombustible corrosion-resistant mesh. The mesh size matters: 1/8-inch is small enough to block most embers while still allowing required airflow.

Replace the mesh on existing vents with 1/8-inch stainless or galvanized steel mesh. Cheapest option — often under $5 per vent in materials.

Replace the entire vent with a WUI-listed ember-resistant vent (brands include Vulcan, Brandguard, and O'Hagin). More expensive but tested to resist both embers and flame.

For dryer vents, install a metal flapper-style vent and keep the lint trap clean. Plastic dryer vents melt and fail open in fire.

Soffit vents, foundation/crawlspace vents, gable-end vents, and roof vents all need treatment. A single un-upgraded vent on the leeward side of the house can be the one that loses you the home.