Ember Defenses

The Dangers of Burning Embers

In a wildfire your home is more likely to burn down as a result of smoldering embers than from any other source. While direct contact by flames provides dramatic newsreels, such contact is often a short, passing pulse of flame that is not likely to ignite your home. In contrast, small embers can remain in contact with a fuel long after the fire front has passed by, then combine to ignite a fire. There are important architectural and structural changes to consider, which are detailed in The Homeowner’s Guide to Wildfire Prevention.

In a major wind-blown fire you can expect dense showers of embers from distant sources, particularly Monterey pines and eucalyptus trees. You can predict where embers will accumulate by observing where wind blow leaves collect.

Ember Prevention for Your Home

The following are the simpler, cheaper things you can do by yourself to defend your home from burning embers.

  • Clean pine needles and leaves from valleys, crooks, and corners, such as dormers, where the roof intersects with the siding, particularly in the high fire hazard season.
  • Screen vents on or under the roof, and in the foundation with 1/8th ” wire mesh.
  • Seal the lower edges of any unsealed siding and keep combustibles away from it, including mulch.
  • Clear combustibles upon or underneath your decks and porches.
  • Pay particular attention to fences and gates, which are often attached directly to a house without a non-flammable barrier and can spread a fire into the house.
  • Decayed wood, encouraged by direct sprinkling, is particularly susceptible to ignition.
  • Thicker 1½” wood is preferable.
  • Consider a wire or metal fence with well-maintained vines.
  • Break up continuity with a gate of non-flammable materials.
  • Use metal, masonry or stucco as a barrier where a combustible fence attaches directly to your house.
  • Never store combustibles against a fence.

Print this list as a checklist: Ember Defenses checklist (PDF).