Cover vents with fine metal mesh to keep embers out
Embers do not need to land on a roof to start a house fire — they can be sucked through soffit, eave, gable and crawlspace vents and ignite...
Embers do not need to land on a roof to start a house fire — they can be sucked through soffit, eave, gable and crawlspace vents and ignite insulation, dust or stored material inside the attic. FireSmart and Firewise USA / NFPA guidance for the home ignition zone includes screening all vents with non-combustible metal mesh fine enough to block ember entry while still allowing airflow. Three-millimetre or smaller stainless steel or galvanized mesh is widely accepted; plastic insect screen is not — it melts in heat. Inspect every vent on the building, including dryer vents, attic gable vents, ridge vents and crawlspace openings. Replace any screen that is torn, missing or made of a material that will not survive direct flame contact. While you are checking, also confirm that nothing combustible is stored directly inside an attic or crawlspace near a vent opening — bags of paper, old curtains, or holiday decorations can ignite from a single ember that finds its way in. Vent screens are an inexpensive upgrade and one of the most effective ember-defence measures available to a homeowner.
Embers can be sucked through soffit and gable vents and ignite an attic from inside the house — and standard plastic insect screen melts in the heat, defeating the whole point.
Source: FireSmart BC — Home Ignition Zone
Last reviewed 2026-05-02.
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