FireWise Home Design
Living in the Wildland/Urban Interface requires rethinking some aspects of your home. In tornado and hurricane areas, homes are designed and built so that they are securely fastened to their foundation. Homes in flood prone areas are typically elevated on stilts or higher foundations. Homes in the Wildland/Urban Interface should be designed with the fire seasons and patterns in mind. Keep an eye towards minimizing the ability of fire to travel between your home and the wildlands. Not surprisingly, a burning house has been the ignition source for more than one wildfire. Protecting your home can also protect the woods you love. If you are designing your home in the interface, you should try to incorporate some of these design principles into your site plan and construction design.
That million dollar view at the top of the hill is why you bought the lot, but as you now know, flames can climb quickly up a slope. Setting the house back from the edge of the slope and avoiding the temptation to install that huge overhanging deck can help prevent fire from racing up the slope to your home.
If you use the FireWise Landscaping techniques you will be employing one of the most effective construction techniques – that is, trying to isolate your home’s flammable structures from fire. But there are other techniques that are very useful. These techniques can be designed into a new construction, or in many cases can be retrofitted into existing homes.
- Using Non-Flammable Breaks in Your Landscape: Wooden fences reach out into your Defensible Space. If they catch fire they can carry the fire directly to your home. Plan wooden fences with fire breaks so that the wood doesn’t actually touch your home.
Likewise, decks and stairways often have lumber that touches the ground. You should consider cladding these structures with some type of metal or other non-flammable material. Better yet, employ the zone concept from the FireWise Landscaping approach and isolate the wooden structure from fire by the use of hardscape, pavers, gravel or stone mulch (Figure 7.10).
Many homes have wooden siding. It is important to keep that wooden siding material from coming in contact with fire as it burns along the ground. In addition to FireWise Landscaping, consider having the siding of your home begin several feet above grade and having a stone or block foundation be what is in direct contact with the ground.
Wooden structures should be separated from flammable plants by a non-flammable break.
Illustration by Rick Holbrook.
- Consider Using Metal Roofing: Metal roofing can be expensive, but it is the most resistant to flames from sparks and embers. Certain asphalt roofing materials are also very flame resistant. Cedar shakes or thatch roofing are very flammable, even when treated with flame retardant materials.
- Consider Using More Fire Resistant Sliding: Wooden clapboard siding is very flammable. Replacing it with aluminum, steel or concrete siding will improve the fire resistance of your home. Brick or stone is also very fire resistant.
- Protect Your Soffits: Remember that heat rises. Fire burning along the ground can cause open areas under roof overhangs or decks to collect heat and cause ignition of the building materials. Simply enclosing them with soffit covers or some type of covering can help to keep flames from gaining access to the underside of the building materials and may help minimize the ignition potential of your house.
Heat rising up against a house under the soffit.
Illustration by Sarah Lynch-Walker.
- Carefully Place Outside Fuel Storage: Above ground propane and oil tanks, as well as firewood piles, are nothing more than large sources of especially flammable fuel to an approaching wildfire. Keep them at least 30 feet from your home. Be sure to rake dried leaves and pine needles away from them, too. A friend who spent a few years as a wildland firefighter had a “D’oh” moment one dry fall day. Feeling smug about raking around her house, she looked over at her propane tank to find it surrounded by years of accumulated dead plant matter. She kept raking! Do not stack wood against the side of the house, unless the location where you stack it is completely isolated from flame using some of the techniques we discussed under FireWise Landscaping.
- Always Use a Spark Arrester in Your Chimney: Fires in fireplaces often shoot off sparks. In the confines of the chimney they can remain hot and burning as they are carried up and out of your chimney. If they land on flammable materials they can start a fire within your Defensible Space