Safe construction or repair in wildfire hazard areas includes the use of flame resistant or fire resistant external materials that can slow down or prevent fire from entering a structure. Below is a list of areas that are vulnerable to wildfires. Click on each to find out how to protect it from wildfire damage.
- Roof material
- Eaves, soffits, fascias, and attic vents
- Chimney
- Exterior walls
- Exterior glass
- Basement and crawlspace
The surface, crevices, and corners of a roof are places where firebrands often settle and ignite. Several options exist to prevent fire damages to roofs:
- Using roofing materials labeled Class A, which are the most fire resistant
- Avoiding wood roofing shingles, no matter what their rating or their type of fire resistant treatment
- Avoiding chemically treated materials or coatings, which often lose their effectiveness over time and leave the roof vulnerable to fire
(Photo shows home without roof shingles. Instead, it has a more fire resistant roofing material.)
Eaves, soffits, fascias, and attic vents are at risk from both firebrands and convection. Mitigation techniques to protect these vulnerable sites include:
- Enclosing or “boxing” them with noncombustible materials protect these areas of a structure
- Using non-combustible screening over attic vents
- Avoiding the use of vinyl materials Although vinyl will not burn, the high temperature of a fire can cause it to melt or fall away, providing the fire with a direct path inside the structure
(Photo shows home damaged by fire with eave, soffit, fascias, and attic vent all pointed out.)
An uncapped chimney may allow firebrands to enter a structure and ignite flammable materials.
This risk can be mitigated by:
- Installing a spark arrestor made from welded wire or woven wire mesh with openings less than ¼-inch wide at the top of the chimney
- Keeping the flue closed when a fireplace is not in use to further reduce the chance of firebrands entering the structure
(Photo shows spart arrestors)
Exterior walls are susceptible to both radiant and convective heat and can quickly transfer a ground fire to the structure’s roof.
Exterior walls can be protected by fire-resistant materials such as:
- cement, plaster, and stucco
- concrete masonry such as stone, brick, or concrete block
PVC and vinyl siding will melt or fall away in relatively low temperatures, and do not provide effective protection from fire damage.
(Photo shows home with brick and vinyl pointed out.)
Glass in windows, doors, and skylights can fracture and fall out when exposed to the heat of a wildfire. This leaves an opening for flames and firebrands to enter the structure.
Using double-paned or tempered glass windows reduces this risk.
- Double-paned windows offer a second layer of protection
- Tempered glass typically resists fracture even at temperatures well above the radiant heat needed to ignite a structure's wood framing
(Photo shows home with windows that are equipped with double-paned glass.)
Wind can push firebrands through the vents in a structure’s basement or crawl space.
The fireproof screening used on roof vents can also be used to protect the vents in the basement or crawlspace.
(Photo shows a home foundation with the fireproof crawl space screening pointed out.)
