Fire-resistant home materials that actually work

Building materials are tested to standards like ASTM E108 (roofs), ASTM E84 (flame spread), and the suite of California State Fire Marshal WUI tests. The labels you'll see on packaging — Class A, ignition-resistant, WUI-listed — all trace back to these tests.

Class A is the highest rating for roof coverings. WUI-listed means a vent or siding product passed the wildland-urban interface ember and flame tests required by California Building Code Chapter 7A.

Best: standing-seam metal, concrete or clay tile, slate. All Class A and very long-lived.

Good: Class A composition (asphalt) shingles. Affordable and widely available.

Avoid: wood shake and untreated wood shingle. Banned in many California WUI areas for good reason.

Best: fiber cement (Hardie and similar), stucco, brick, stone, metal panel.

Acceptable: heavy-timber 1-inch-plus solid wood with no gaps, ignition-resistant treated wood.

Avoid: vinyl (melts and exposes sheathing), untreated thin wood, T1-11 plywood siding.

Best: dual-pane with at least one tempered pane. Tempered glass resists radiant heat far longer than annealed.

Avoid: single-pane glass anywhere on the home, large unprotected picture windows facing vegetation.

Best: noncombustible (concrete, steel framing with composite top), or WUI-listed composite boards.

Acceptable: nominal 1-inch solid wood with tight gaps and clean undersides.

Avoid: thin plastic-only composites that melt, and any deck with leaves packed underneath.

Best: WUI-listed ember-resistant vents (Vulcan, Brandguard, O'Hagin and equivalents).

Acceptable: standard vents retrofit with 1/8-inch noncombustible corrosion-resistant mesh.

Avoid: any vent with 1/4-inch mesh, plastic dryer vent hoods, and gable vents with louvered slats only.