Firewise Building Materials

As a homeowner, you are responsible for reducing your home’s vulnerability to wildfire. One of the most important steps to accomplishing this goal is to use building materials that are resistant to ignition from a wildfire.

Building Codes for New Construction

If you have not built your home yet, try to place structures on flat ground. Fires burn uphill more rapidly than down or across a flat. Avoid draws, as they can serve as a chimney, creating more intense fires that spread rapidly with uphill drafts.

Many communities in Idaho have adopted all or part of the 2006 International Wildland/Urban Interface Code and the 2006 International Fire Code. These codes set standards for new construction in the following areas:

• Ignition resistant building materials
• Ignition resistant building techniques
• Driveway access for fire apparatus
• Vegetation plans for new residences and subdivisions that provide defensible space
• Sprinkler systems on structures over 5000 sq. ft.
• Proper address labels for emergency response
• Other restrictions on outdoor burning, outside storage, etc.

Specific examples of countywide codes and building ordinances in the WUI are available from the Idaho State Fire Plan Working Group

Retrofitting Your Existing Home

These components are usually the most expensive to replace in a retrofit, but will be well worth the price if your home is threatened by a wildfire.

• The roof. The roof is often the most vulnerable part of your home and outbuildings to ignition during a wildfire. Always use a rated roofing material. Rated roofing materials range from Class C (able to withstand light exposure to fire, like asphalt shingles) to Class A (able to withstand severe exposure to fire, like metal roof seaming). Wood shake roofs are not rated and in many cases, offer almost certain ignition of your home.
• Siding. Use of fire-resistant materials on exterior walls will provide a greater level of protection to your home. Wall materials that resist heat and flames include cement, plaster, stucco, and masonry, such as stone brick or block. If you have vinyl siding, consider using metal screening over openings that will become exposed if the siding melts or falls away.
• Windows. Exposure to the heat of a wildfire can cause glass on exterior walls to fracture and collapse, allowing firebrands to enter the home. Use of double-paned or tempered glass can help reduce this risk by providing an added layer of protection. Screens should have metal frames as well as metal, not plastic, mesh.

There are many relatively inexpensive things you can do now to better protect your existing home from wildland fire.

• All fuels should be removed from overhangs and other attachments such as room additions and bay windows. Regularly remove debris from roof, gutters and other area s, such as corners and under stairs, where often accumulates. Special attention should also be paid to the areas under decks, porches, carports, and around fences.

• Eaves, fascias, soffits, and vents should be “boxed” or enclosed with metal screens to reduce the size of the openings. Vent openings should be screened to help prevent firebrands or other objects larger than 1/8” from entering your home and you should have spark arresters on your chimneys.
• Outdoor furniture and accessories are common sources of ignition. Consider replacing wooden or wicker tables and chairs with ones made from nonflammable material such as metal and glass. Cushions, umbrellas, furniture covers, door mats, planters and window boxes are all areas where embers can collect, smolder and start a fire well after the flaming front has passed.
• Pay attention to places where combustible materials meet each other, for example, where a wooden fence is attached to the wooden stairs that leads to a wooden deck. Separate these areas with a span of non-flammable material.
• Store boats, campers, and other recreational vehicles in an enclosed area or away from your home.