Protecting Residences From Wildfires


Although many of the most important actions in providing fire safety for a structure located in a wildfire hazardous area take place during the planning, designing, constructing, and landscaping phases they do not end there. Maintenance must begin the day the occupant moves in and continue so long as the building stands, or all the original built-in protection may be in vain. Many cases have been documented wherein a structure, once reasonably fire-safe, burned down after it or the area around it had been allowed to deteriorate (e.g., birds' nests under the eaves, accumulations of leaves and dry grass in yard and gardens or on roofs, regrown brush). Roofs also deteriorate in varying lengths of time and require repair or replacement (Alger 1971, Los Angeles County Fire Dep. 1970, Los Angeles County 1973, Wilson 1962).

Roofs and Rain Gutters

The roof is the most critical point in maintenance as well as in construction for the protection of a structure from a conflagration in chaparral or other wildland. The most common problem arises from the accumulation of dead leaves or needles which can build up to considerable depth in the troughs of peaked roofs, in rain gutters and behind the wall extension above the roof line that is commonly used with flat roofs. Any place where windblown leaves will accumulate is an ideal place for windborne firebrands to drop. Under these conditions even so-called "fire-retardant" roofs will ignite. Another attractive place for firebrands to ignite is in birds' nests under eaves and the ends of unplugged tiles. The obvious preventive solution is to remove all such accumulations before each fire season and at least once during the season (Alger 1971, Los Angeles County Fire Dep. 1970, County Sup. Assoc. of Calif. 1966).

An older home is no more immune to destruction by wildfire than is a new one. Its roof is certain to require repair or replacement eventually. When this time comes it is only good business as well as insurance for future fire safety to upgrade the fire protection rating of the materials used. The UBC and many local ordinances state that whenever 25 percent or more of a roof is replaced it must meet the standards for the fire zone in which it is located, and this is a good rule of thumb for use in wildfire hazardous areas (Building News, Inc. 1977; Intl. Conf. of Build. Off. 1976).

Proposed Standards:

  1. Remove all loose flammables (e.g., dry leaves or needles, paper, birds' nests) from roofs, eaves, and rain gutters at the beginning of each fire season and any time they accumulate to a depth of 1 inch or more.
  2. Not more than 25 percent of the area of a roof should be replaced within any 3-year period with materials that are not approved for new roofs in the same wildfire hazard severity classification area.


Yards, gardens, landscaped areas, and fire protection clearings require a great deal of maintenance. No vegetation is immortal, and flammable dead vegetative material is going to accumulate. Often such accumulation is not readily apparent to the unpracticed eye. Individual dead twigs and branches may be hidden by live exterior foliage. Dead leaves may be under or behind live plants. Annual grasses and weeds can grow almost anywhere. All such dead vegetative material should be removed and disposed of before it becomes tinder for carrying a wildfire to the house (Los Angeles County Fire Dep. 1970, Orange County Bd. Sup. 1976, Los Angeles County 1973, Smaus 1978 b).

Even if vegetation is kept pruned and weeded, yards will collect a certain amount of flammable litter. Leaves and needles fall. Scrap paper blows in on the wind. All such material should be regularly collected and disposed of. In many areas they must be hauled away to an approved landfill either by a refuse disposal service or by the occupant because local air pollution regulations prohibit burning. In those areas where burning is permitted it should be done only in an approved incinerator under permit from the local fire protection agency. Open debris burning has caused a good many conflagrations in the past, although it has been somewhat rare in the past 10 or 12 years due to recent restrictions and controls (Alger 1971).

Because of natural plant succession, clearances around structures for fire protection will most invariably revert to native vegetation unless positive steps are taken to maintain the clearance. Maintenance can be accomplished in several ways: by skillful use of herbicides, by browsing and grazing livestock, by disking, by hand chopping or grubbing, or by prescribed burning (table 4).

Many people living in wildfire hazardous areas keep horses and some keep cattle or sheep. Research by the United States Forest Service and California Department of Forestry has shown that goats enjoy a diet of chaparral and are very effective at maintaining fuelbreaks. Horses, cattle, and sheep are primarily grazers and will only browse on very young succulent chaparral but are good at reducing the fuel loading of dry grass. The method or combination of methods used is not important as long as thought and effort are put into maintaining the fire protective qualities of the clearing (Orange County Bd. Sup. 1976, Los Angeles County 1973, Green 1977).

Proposed Standards: Remove and dispose of all dead vegetative and other flammable material, in amounts which will carry ground fire or convey fire from one bush or tree to another, by means permitted by State law and local ordinance.


It is common in suburban, and in rural areas especially, to store certain flammable materials outdoors, often stacking them against the side of the house, garage, or barn. The most common such materials are firewood, lumber, and hay, but there are many others. This practice is very dangerous as far as the fire safety of the structures is concerned. Stored flammable materials should be under cover to prevent windborne firebrands from landing on them. If covering them is not feasible or it is not possible to store them inside the building then they should be separated from the building by enough distance to save the building from ignition should the materials catch fire. It is still the best practice to cover them with sheet metal or some other fire-retardant material (Alger 1971, Los Angeles County Fire Dep. 1970, Wilson 1962).

Proposed Standards: Store flammable materials either:

  1. Inside of properly designed and constructed fire-safe buildings, or
  2. Separated from any buildings by the same minimum distance required for building spacing in the wildfire hazard severity class in which the structures are situated.

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