Roofing Shingles, Cedar Shakes, Roof Maintenance
How long a cedar shake or shingle roof lasts depends on a variety of factors, including the quality of the wood used, the quality of the installation, environmental conditions and whether or not the roof is maintained.
By Susan M. Brimo-Cox
have been used for hundreds of years. And as a roofing material, they offer more than aesthetic appeal: Wood is a renewable resource, has insulating qualities, and is wind and impact resistant. “Cedar is also lightweight and naturally decay-resistant,” reports David Linton, manager of the Cedar Shake & Shingle Bureau, a non-profit industry association. You’ll find cedar used around the world, but about 95 percent of production is applied on buildings in the United States, says Linton. “Canada, Europe, the Caribbean and other areas make up the balance of product consumption.”
What’s the difference between shakes and shingles? How they are cut. Linton explains, “Shakes are either hand-split and resawn (split on one side) or tapersawn (sawn on both sides). Shingles are sawn on both sides. There are a variety of product lengths and grades within each of these three broad categories. Shakes are typically used on roofs. Shingles are the most popular sidewall product, however, they are also widely used on roofs.”
How long a cedar shake or shingle roof lasts depends on a variety of factors, including the quality of the wood used, the quality of the installation, environmental conditions and whether or not the roof is maintained. Cedar shakes and shingles may also be pressure-impregnated with preservatives for use in areas with high humidity. Pressure-impregnated fire-retardant treated products are often installed in California.
“During the boom years of the ‘60s, ‘70s and ‘80s, cedar shakes were very popular,” observes Kevin Curry, owner of California Roof Savers Inc. in Orange, Calif. Put that together with knowing that typical warranties for cedar shake and shingle products last 20 years to 25 years and it becomes obvious that a lot of opportunity exists up on the roof. Like other exterior wood surfaces — such as wood siding or decks — maintaining and treating a cedar shake or shingle roof can add years to the life of the roof. “There are lots of studies that show wood shake roofing benefits from treatment,” observes Curry. “Painters treat wood. If you have a choice between using a protectorant or not using anything at all, which is better? Preserving it, of course.”
Given the choice between restoration and replacement, homeowners will likely opt for restoration as a matter of dollars and cents. Five years ago, Walt Kingen purchased a 43-unit apartment complex in central California. This year he had the 22-year-old cedar shake roof restored. “I realized the roof needed renovation or replacement. [After having the roof inspected,] I was assured the shakes were in good condition and that they could be restored. It was a far more economical option,” Kingen says. He estimates it would have cost $80,000 to $90,000 to replace the 30,000-square-feet of roofing. The restoration, at about $17,000, cost about 20 percent of a new roof. “Small patching and repairs were made where needed, and the ridge cap was replaced, but the restoration made a considerable positive difference. The roof is more resilient and we gained another 10 to 15 years out of the roof,” he adds.
It’s not unheard of for wood roofs to last a hundred years or more if properly maintained and treated. Curry suggests the best situation is to “start within five years of when the roof is installed, and retreat it every five years for an indefinite lifespan.”
“The goal of restoring a wood roof is to have a roof that looks like it’s just been installed,” explains John Sindelar, president of Shake Savers Inc. in Cleveland. Sindelar recommends a four-step process.
The first step is to investigate the roof. “You have to assess the roof and make sure the wood is in good condition,” Sindelar says.
Cleaning the roof is the second step. Sindelar uses a powerwasher, as do other contractors. “I use a powerwasher to remove dead wood cells, debris, moss and mildew,” Sindelar explains. “There really isn’t a standard, but typically the range is 1,500 psi up to 3,500 psi, depending on the training and skill level of the person doing the powerwashing.” He points out that a wood roof is an irregular surface, not like concrete, siding or a car, and you can easily blow it off with too much pressure.
The third step is spot repair. Sindelar advises, “Replace all pieces that have no protective value (if they’re rotten, broken or exposing nails underneath). Check the flashing and gutters. Make sure the roof is weather-tight and functioning.” Contractors that don’t have a roofing background or the experience needed should consider subcontracting the repair work to a roofing professional.
Treating the roof is the fourth step.
All kinds of materials have been used to treat cedar roofs. Curry says, in the past, Indians in the Pacific Northwest used fish oil. Reports of diesel fuel, motor oil and linseed oil also are heard. But modern products are easier and safer to use.
When selecting a coating for a wood roof, make sure the product is appropriate for cedar roofs. Never use a waterproofing, sealant or other coating that creates a film or otherwise encapsulates the wood. Wood roofing needs to breathe, therefore, penetrating oil finishes are best for cedar shake and shingle roofs. An airless sprayer is the preferred method of application.
“The reason shake roofs deteriorate is because natural oils are washed and baked out of the wood by rain and the sun’s UV rays,” explains Jake Clark, president/owner of Armstrong-Clark Co. in Long Barn, Calif. “When the wood turns gray, it means the natural oil has left the surface of the shake and it’s time to treat it.”
Using penetrating oil puts oil back into the wood. “It penetrates and protects from the inside,” says Beth Rechin, associate brand manager of the Flood Co. in Hudson, Ohio.
Clark agrees. However, “penetrating non-drying oils best duplicate the oils given to wood by nature. They also wick up under the next row of shake to protect areas you can’t spray.”
Rechin recommends angling the sprayer to saturate the butt end of the shakes or shingles and all the surfaces you can reach. She says products containing fungicide help ward off the mold, mildew and moss that can be a problem for wood roofs. UV protection is also a plus.
In between treatments, Rechin says, it’s important that roofs be kept clear of debris. “Debris, such as leaves, pine needles, etc., holds moisture, providing ideal conditions for moss, mold and mildew. Seasonal removal of debris will help keep the shakes in sound condition.”
Mike Stephens, owner of Mike’s Painting and Maintenance in Merced, Calif., has been restoring and treating cedar roofs for about 10 years. He says there were many times when he’d do an estimate for an exterior painting project and noticed the cedar shake roof. So he would present an estimate for a complete exterior refurbishing. “It’s good to have a package deal to offer. A lot of homeowners appreciated it and it never hurts to mention it — a lot of homeowners weren’t aware that their roof needed help or that I could do the work.”
Cross selling can certainly increase a contractor’s business. Stephens points out, “Painters have pressure-cleaning and spraying equipment, the two go hand-in-hand.” Restoring and treating cedar roofs is now about 30 percent of his business. For contractors thinking about expanding into roof cleaning and treating, Stephens suggests talking to experienced roof coaters and manufacturers of roof coating products. “Be sure you follow the proper procedures. Use a quality product and apply it according to the manufacturer’s instructions. And make sure the homeowner understands your warranty is for the cleaning and coating — not the structural integrity of the roof or shakes.”
Depending on the area of the country, cedar roofing has to withstand exceptional weather conditions, as do other roofing materials. In the south, it’s intense sun damage. In the southeast, it’s hurricanes. In the Pacific Northwest, it’s extremely wet conditions. In the north, there’s the snow. Fortunately, cedar roofing is well suited for many of these conditions. For example, wood roofs are resilient in earthquakes and can withstand the pounding of hailstorms. However, the formula of the protective coating used to preserve the roof and the interval of treatment may vary.
In California, cedar roof advocates have been battling a special challenge — an anti-wood roof groundswell in the wake of all the fires in Southern California. Curry observes, “All of a sudden wood shake roofs were blamed [for the fires]. Actually, in a fire storm, it doesn’t matter what kind of roof you have.”
“Pressure-impregnated fire-retardant treated cedar shakes and shingles are available and do meet a number of stringent testing standards,” reports Lynne Christensen, Marketing Manager for the Cedar Shake & Shingle Bureau.
Nonetheless, some cities in California prohibit wood roofs, while others require fire-retardant treated wood. The apparent goal is to eliminate all non-fire-retardant wood rooftops in the state. Topical fire-retardant treatments will not pass muster. Tests are underway to learn if application of certain wood preservatives will affect the fire-retardant qualities of treated wood.
Special challenges aside, regular treatment and restoration can improve and beautify a cedar shake or shingle roof. According to Clark, treating or restoring cedar roofing is “a real service and benefit to a homeowner. The curb appeal is huge!” As a viable alternative to replacement, it’s an ideal new market for painting contractors.