Siding (cladding) is an important esthetic attribute for houses, but it also has a key role as part of a protective enclosure to help shed rain, while permitting excessive vapor to move through and out of the house.
See a video demonstration showing some things to keep in mind about siding and wildfire.
|S1||Is the siding combustible (wood, vinyl, or wood plastic composite material)?||Combustible siding and interlocking lap:|
|Combustible siding provides a rapid vertical path for flames to reach vulnerable portions of a house such as the eaves or windows. If the siding is combustible, it should have interlocking lap construction and should be carefully maintained.||
|S2||Are there any other gaps (openings) located in the building envelope?||Building gaps:|
|Other gaps may include, for example, reentrant corners (an interior corner).|
|S3||Is the trim combustible?||Combustible trim:|
|Combustible trim materials can compromise noncombustible siding.||
|S4||Is there a combustible fence or gate attached to the structure?||Combustible fence:|
|There are several reasons for fences to be of concern. For one, a combustible fence or gate attached to a structure is a threat if it catches on fire, and can act as a wick, bringing fire the house. The fire can arise in a number of ways. One is that debris (leaves, trash, etc) often collect at the bottom.||
|S5||Are there any man-made fuels within 6' of the siding?||Man-made fuels:|
|Man-made fuels include construction materials, newspaper or trash, coir or wood doormats, arbor or trellis, propane tanks, combustible lawn furniture, firewood pile, gas-powered vehicle, carport or detached garage, gas-powered lawn tools, flammable bins or cans, outbuildings, and other structures.|
|S6||Is there any vegetation within 6' of the siding?||Vegetation:|
|Not all plants are ‘good’ or ‘bad’. The size, location, structure, and condition of vegetation determine its risk to a home. Plants closer to a home are a greater risk to a structure. Any plants near a house should be pruned, regularly watered (preferably using drip irrigation system) and any dead material removed, including at the soil level. Along with these precautions, we don't recommend using bark or other combustible natural materials as plant bedding. Embers can land in this, smolder, and later go into flaming combustion. In addition, the smaller the better, especially close to combustible siding, under a window, or inside a corner. Better yet, consider using ground cover wherever possible next to combustible siding or near windows for any type of siding.|
|S7||Are there unscreened vents or screened vents with a mesh size >1/4" (e.g., crawl space, room containing gas water heater)?||Vents:|
|Evidence from recent wildfires has shown that vents are an easy entry point for burning embers and (not surprising) flames. Most vents incorporate a screen at the inlet. Most building codes stipulate a minimum mesh size of 1/4-inch to minimize plugging of vent holes with accompanying reduction in air movement. Smaller mesh screen is easier to plug up, whether by air borne debris, or as shown in the photograph below, being painted over during routine painting.|