At Issue : Should Wood Roofs Be Banned? : YES : Most Homes Lost to Fire Since 1961 Had Them

The City of Los Angeles has taken progressive steps to protect its citizens and their property from brush and structure fires, especially in areas of high winds, dense brush and native vegetation.

Of continuing concern in these areas are wood roofs, which have been identified as being a major contributing factor in fires. Most of the 931 homes damaged or destroyed in the City of Los Angeles during major brush fires since 1961 had wood roofs.

Examples of fires involving wood roofs include Santa Barbara, 1977--234 homes destroyed; Anaheim, 1982--362 apartment units; San Diego, 1985--87 homes; Pebble Beach, 1987--31 homes, and Houston, 1979--26 apartment buildings.

Further, during last December’s Porter Ranch-Granada Hills brush fire, 16 of 17 wood roof homes on one street alone were damaged or destroyed. In every instance, the wood roof surface was the first to ignite and in many cases contributed to the fire exposure of other homes through radiated heat or flying brands.

Although these roofs were not pressure-impregnated as required by the present building code, adopted in 1982, they were treated by the hand-dip process, which at one time was accepted by the city of Los Angeles in conformance with the 1970 building code.

The failure of these roofs, which were less than 20 years old, raised a serious question:

Will the pressure-impregnated wood roof provide an adequate level of fire protection throughout the life of the roof?

The wood shake and shingle industry has developed several methods that have improved the fire retardancy of wood roofs. However, the dry Santa Ana winds subject even the new pressure-treated shakes and shingles to adverse conditions not experienced during tests.

In addition, the test requires only a 10-year natural weathering test for wood shakes or shingles. This is not an adequate testing period, because most wood roofs in Southern California will last between 20 to 30 years.

So far, approved pressure-impregnated wood roofs have passed only the five-year natural weathering test; the 10-year test is scheduled for 1992.

There is existing residential development in the mountains and high-wind-velocity areas in the city that interface with brush, and there will be development there in the future.

The effectiveness of the Fire Department is extremely compromised in these areas, which typically have a limited water supply and limited access.

Fires that ignite roof brands and winds that propel these burning roof fragments ignite spot fires several blocks away from the original source.

Because of these conditions, wood shake or shingle roofs should be banned in the mountain fire districts, fire buffer zones and restricted roof zones of Los Angeles, which cover those parts of the city that experience increased fire danger due to climate, geography and topography.

Furthermore, when more than 10% of a roof in these restricted areas is replaced, the entire roof would be required to be brought up to code.

Finally, wood shake or shingle roof covering systems in use in all other areas of the city must undergo and satisfactorily pass fire-retardancy tests for a period of 20 years to retain approved status as a roof covering.

This potential of igniting roof surfaces and producing flying brands will continue to be a major contributing factor in the spread of fires unless a ban on new wood roofs is passed. The citizens can no longer afford the risk that wood roofs in mountainous, windy areas impose.

READER IDEAS FOR AT ISSUE

Readers who have ideas on topics they would like to see explored in At Issue should send them to Real Estate Editor, Los Angeles Times, Times Mirror Square, Los Angeles 90053.