Q-I just purchased a home that has a cedar shake roof. My concern is maintenance. The previous owner of the house says I don’t have to do anything. My intuition tells me he is wrong. Is there anything I should be doing to maximize the life of the roof?
Also, I am very concerned about the possible fire hazard of a cedar roof. Is there a danger? Are cedar shakes really that great when compared to other roofing products?
A-Cedar shake roofs have many positive qualities. When installed properly, they are extremely wind resistant. Believe it or not, they actually have twice the insulating value of standard asphalt shingles. Hail does not easily damage cedar shakes. When treated with certain chemicals, cedar shakes can be made permanently fire-resistant.
Cedar shake roofs, no doubt, have a certain amount of prestige as a roofing material. That explains why many of the other roofing product companies manufacture materials that simulate real cedar shakes. The texture, color and appearance of a cedar shake roof is undeniably appealing.
However, this beauty comes with a price tag. Cedar shake roofs do require a certain amount of maintenance to maximize their useful life. The enemies of cedar shakes, as you might expect, are water and sunlight.
Many people know that cedar contains high amounts of naturally occurring chemicals that help preserve the wood. These chemicals are called extractives. They dissolve easily in water. Need I say more? In certain conditions, rainfall can leach these chemicals from the cedar shakes in less than 10 years.
Ultraviolet light (UV) from the sun actually causes the surface cells of the cedar to break down. This microscopic refuse is washed away with each rainfall. UV rays also cause very tiny cracks to develop and allow water to drive deeper into the shakes. This simply accelerates the process of dissolving the extractive chemicals.
The key to maintaining a cedar shake roof is to keep it dry. Yes, I realize that sounds funny. What I mean is that after a rainfall, a cedar roof needs to dry out as rapidly as possible. The shakes must be free of moss, fungus, debris (twigs, pine needles, leaves, etc.), or anything else that can trap and hold moisture. Overhanging tree branches must be sufficiently high so as to provide good air circulation above the roof.
Chemical preservatives are available that can be applied to cedar shakes. These preservatives, when applied to clean, dry cedar shakes, can add years of life to a cedar roof. Most of these chemicals can be applied with a hand-held sprayer. Professionals who treat cedar roofs for a living have pressurized machines that allow them to do large roof areas in a short amount of time.
If you decide to clean and treat your roof yourself, you need to exercise extreme caution. You need to protect yourself from the dangers of falling. You need to protect your roof from the dangers of cleaning. Cedar shake roofs that are damp, covered with moss, or any object can be extremely slippery. I once stepped on some moss on a low pitched cedar roof and ended up at the gutter before I realized what had happened.
Because cedar is a soft wood, mechanical power washing equipment in untrained hands can seriously damage your shakes. Cedar that is covered with damp moss is even softer. A power washer that has too much pressure or is too close to the shakes can erode the wood. Simply use some common sense when cleaning.
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Have questions about the remodeling process? Write to Tim Carter, c/o The Chicago Tribune, P.O. Box 36352, Cincinnati, Ohio 45236-0352. Questions will be answered only in the column.
For a listing of excellent preservatives for use on cedar shake roofs, cleaning suggestions and other tips on maintaining cedar shake roofs, send $2 and your name and address to Tim Carter at the above address. Ask for Builder Bulletin No. 72.
You can obtain a free order form for a wide variety of individual job bid sheets by sending a business-size, self-addressed stamped envelope to the same address.
