Are Wood Shake Shingle Roofs Fire Resistant?
Wood shake shingles and wood roofs are a major fire concern and pose a serious fire risk for homeowners, families, and communities throughout the United States. Regardless of the way the wood shake shingles are cut (hand split, tapersawn, heavy shakes), if it is a wood-based roofing material, it is a dangerous fire concern for a home.
So, are Wood Shake Shingle Roofs Fire Resistant?
The wood shake shingle industry developed wood roofing materials, which are labeled as ‘treated with fire retardant’, to meet increased building code requirements. As fire concern and flammable conditions of un-treated wood became an issue, fire retardant chemicals were applied to help reduce fire risk of wood roofs. As fire resistance of treated and non-treated roofs came into question, some governmental agencies have banned the use of wood shake shinlges and wood roofs entirely.
Building codes have been established to protect homes within wildland urban areas from firestorms. Establishments and building codes help keep citizens aware and informed of the protection that can be taken to ensure proper fire safety. The objective of these establishments is to protect citizens and properties from fire.
Fire resistance ratings have been established for building materials and roofing products, there are three resistance ratings that are Class A, Class B, and Class C rated.
Class A - can withstand severe fire test exposure
Class B - can withstand moderate fire test exposure
Class C - can withstand light fire test exposure
Clearly it would be most beneficial to communities and homeowners if all roofs in fire danger communities were Class A fire rated. However, for homeowners that have a wood shake shingle roof, a serious problem exists for firefighters to distinguish treated roofs from untreated roofs during a fire. In the event of a major fire, firefighters may need to perform a triage operation (which house to save first), and in some cases the distinction between treated and un-treated wood is extremely difficult. It is also important to know that burning embers from wild fires can travel and easily spark ignition on a wood roof as wood roofs are very susceptible to fire ignition from outside sources such as flying embers from a nearby fire.
Pressure treated wood shakes and shingles receive a Class A rating when installed with a fire resistant underlayment. Fire protection is provided by pressure impregnating fire retardant polymers into the innermost cells of wood. However, many times there are no required inspections or tests after installation of wood roofs to determine the status of the fire retardant. Often times it is also difficult to tell when, or if, a roof was fire treated or when it has lost its original treatment by inspection.
Fire Concern and Insurance Issues with Wood
Wood is naturally flammable and a wood roof adds significant fire concern to your home, especially if you live in a mountain community or an area that has a history of wild fires.
Wood shake shingle roofs are becoming banned and even illegal in many areas of the United States because of the danger they impose to your home and the surrounding homes around you. The older and more dry a wood roof gets, the easier it is to catch fire. In fire prone states like California for example, it is very difficult and almost impossible to get an insurance company to cover your wood roof.
So, what causes Wildfires?
While it is difficult to provide one simple answer, low annual rainfall, low humidity, dry conditions, and high winds all contribute to a disastrous situation for any fire. History has shown that high wind conditions can take a seemingly innocuous fire, even under control, and spread firebrands to structures with wood roofs causing great property loss. In the event of a fire, flames can rapidly spread to adjacent homes by means of flying embers landing on wood roofs.
The impact on an individual homeowner, when changing roof materials, may be negligible when all costs for the materials are amortized over the life of the roof covering. When you consider installation costs, life expectancy, and warranty, treated wood shakes can be four times the cost of concrete tiles, and twice the cost of coated metals and synthetic materials. The choice of a roofing product may also be influenced by insurance.
Insurance companies are now recognizing the inherent dangers of wood roofs and may impose a premium for such a roof, or simply refuse coverage. In California and many other states, many insurance companies provide a discount for roofing with impact resistant and fire resistant roofing products.
