What does a wildfire-resistant house look like?
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Instead the practical aim is to make a house less susceptible to the three main fire threats, which buys time both for people to evacuate and for firefighters to arrive. The longer it takes for a house to start burning, the better the odds that firefighters can get there and stop the flames, Fippinger says. Stopping them before they find purchase in the built environment is critical: Once a single house catches fire, “it is then propagating the spread of the fire into the neighborhood,” Barrett says, “and that’s very distinctive with wildfires, in contrast to other hazards. You do not see that with floods; you do not see that with hurricanes.”
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One of the first, and often easiest, places to start when hardening a home to wildfire is what experts call “defensible space.” This is a bit like a home’s personal space. Essentially, you want to reduce or eliminate any combustible material within five feet of the house to reduce the risk from embers and within 100 feet to protect against active flames and radiant heat. An individual home’s defensible space can overlap with neighboring homes or other structures, especially in densely populated areas, so one homeowner’s choices in this regard can affect the risk for neighbors as well.
Within the defensible space, it’s important to consider the flammability of plants, landscaping materials (such as mulch or pine straw), fencing, vehicles, trash cans, sheds or other outbuildings, decks and outdoor furniture.
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A range of factors affect the relative risk of a roof catching fire. The safest roofs have simple shapes—few or no dormers (protruding structures, usually with windows) or other architectural features where debris or embers can collect—and are made from noncombustible materials, such as asphalt or metal. Tile roofs are popular in some areas, and though they are noncombustible, they can crack naturally or from various stresses, creating crannies that can trap flammable debris or flying embers. Debris such as leaves should be regularly cleared from roofs and gutters, and the latter can be covered for further protection.
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Ideally, exterior walls should use noncombustible fiber cement or stucco materials instead of vinyl siding or wood. “They’ve now made very decorative cement and stucco options that are easy to install, that aren’t super expensive,” Kerber says.
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