The Kindling Roof Debate Continues

June 5th, 2014

Wildfires have ravaged several communities. Between 1970 and 2003, warmer and drier conditions increased the burned area in the western U.S. mid-elevation conifer forests by 650%. The National Climate Assessment Report issued May 6, 2014 by the U.S. Global Change Research Program stated: Wildfires are a natural part of the forest ecosystem in the Northwest, but warmer and drier conditions have increased the number and extent of such fires.

Cedar shakes and wooden shingles may have been the favorite choice 100 years ago, but their time has passed. Many homeowners love the look of a wooden roof, but it is costly to buy, install, and maintain. However, the most serious reason cedar wood shakes and wood shingles should be avoided is that they are a dangerous fire hazard. Although some are treated with a fire retardant, that retardant deteriorates over time.

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When choosing material for a roof, homeowners must first consider the possibility of fire devastation. A wood roof that would serve as kindling to a fire should not be the primary protection for a home. This is especially a concern if that home is in a region prone to lightning strikes and wildfires. Wood shake roofs were blamed for helping spread the devastating Waldo Canyon Fire in Colorado. The city of Ketchum, Idaho is considering a ban on wood shakes and shingles for new construction after the massive 174-square-mile Beaver Creek Fire, which heavily damaged homes in that central Idaho area. There have been many cases in which even though a fire line was cut around a house to stop an approaching fire, hot embers landed on the roof and ignited the structure. The latest version of the International Fire Code doesn't ban wood shingles, so local governments must enact such a ban.

One option that may be considered by homeowners is to cover an old roof with new roofing materials. There are several drawbacks to doing this with both wood shake and wood shingle roofs. In the International Residential Code (IRC) is a ruling, RC R907.3, which describes the ordinance for re-covering versus replacement: New roof coverings shall not be installed without first removing existing roof coverings where any of the following conditions occur:

  • Existing roof or roof covering is water-soaked or deteriorated to the point that the existing roof or roof covering is not adequate as a base for additional roofing.
  • Existing roof covering is wood shake, slate, clay, or asbestos-cement tile.
  • Existing roof has two or more applications of any type of roof covering.

Covering an old roof with multiple layers makes it hard for firefighters to quickly vent the roof. New wood-shake roofs will continue to be an option for homeowners, at least for a while, in two neighboring California towns, Portola Valley and Woodside. Given the current severe drought and a shake roof's potential to spread a fire, the Woodside Fire Protection District proposed a ban on new shake roofs. But this past January, after hearing arguments for and against the ban, the Portola Valley and Woodside council members, meeting jointly, decided to wait for more data, including data on weathering effects beyond 10 years. Council members considered incentives to encourage residents to replace aging ignitable roofs, of which they believe are too many to count within the district.

Wood shakes traditionally have posed significant problems in fire spread and ember propagation. Shake roofs can be a source of firebrands, burning embers that become airborne and spread a fire far beyond its origin. Increasingly, many insurance companies won't insure houses with shake roofs, even those treated for fire resistance. Over time, treated shakes lose their resistance, which puts a home and neighborhood at risk.

The recent action by the Woodside Fire Protection District was given after hearing from treated shake producers. They told the council members of tests that show shakes charring rather than burning, and that the charring would stop without an external flame to encourage it. However, insurers in that area have a different view. Representatives told the councils that there are many different views among the 135 insurance companies in California. Homes in the hills above Woodside, are particularly hard to insure, especially those with shake roofs. A non-standard insurer may take it on, but at two to three times the usual premium.

Homeowners in Burbank, California, who have yet to comply with a decades-old ordinance requiring them to remove and replace their wood roofs have just a few months left to do so. The law was passed to make homes more fire resistant. Residents with exposed wood shakes or shingles on the roofs of their homes have an August 14 deadline to have them removed. Those with “roof-overs,” (wood shingle or shake roofs covered by another type of roofing material), have until 2020. The extension was granted by the city two years ago at the request of local real-estate agents and homeowners who argued that the expense would be unaffordable during the recession. “Wood shakes are basically like having a pile of firewood on top of your house,” said Burbank Fire Capt. Peter Hendrickson. “Most of the wood shakes are years old and very dry. During hot, dry conditions, they dry out just like brush does.”

The best advice for those with wood shake roofs is to be proactive. Don’t wait for a wildfire or hurricane to strike. Have your wood shake or wood shingle roof inspected now. If replacement is recommended, look into the many possibilities of architectural asphalt shingles, including shake-style, at