What roof treatments should not be used?

A roof offers strength, durability, insulation, and beauty to a home. With everything your roof does for you, shouldn’t you treat it right? Years of exposure to the weather can drastically change its quality. A good roof treatment can help. But which ones can help, or hurt?


Besides enhancing the look of your home, treatments help to extend the life of your roof. In fact, you lose three years off of the expected life of your roof for each year that it goes untreated. Through the interaction of sunlight and rainfall, cedar shakes and shingles can lose virtually all their natural protectants in a short time.

After about five years, most cedar roofs begin to show signs of cupping, curling, splitting, and decay. Unlike most roofing materials, however, cedar shingles and shakes can be restored and maintained through proper care and treatment. They are a unique and beautiful house top covering, and should be treated with utmost care and regular maintenance.

One of the common mistakes of many roof cleaning companies is that they treat all roofs the same. Whether is it is a composition, tile, composite, metal or cedar shake roof, they want to apply their “one solution fits all” practices to all roof types.

Many roof cleaning companies will show up and remove live moss from your roof shingles. But are they doing more harm than necessary to the integrity of your roofing material? Some professionals employ moss treatment, to actually kill the moss first. In most cases, the moss disappears after a period of time with treatment alone. Treatment is in fact better for the environment than prematurely re-roofing your home because of accelerated wear.

The type of treatment you use could mean the difference between life and death for your roof. A good preservative treatment should be 100% oil-based and contain a moss, algae, and fungus retardant, as well as a water repellent and insecticide. Many companies use outdated, toxic treatments that require a commercial license to apply. Others use cheap and ineffective emulsifiable water-based treatments. These are not wood preservatives. They are low-cost fungicides.

Pressure-washing is considered to be a violent way to clean wood shingles and shakes. It removes granules and doesn’t remove all the live moss. Pressure washing cannot remove moss roots from your roof, and moss may start growing again in about six months.

Pressure-washing also forces water into and between the shingles. Shingles are not waterproof, but water resistant. They’re designed to shed rain water, and depend on tar and gravity to carry water off the roof quickly. Without this protection, water and debris from the roof plugs gutters and downspouts, and overflows onto the house and around the foundation.

Zinc strips won’t kill existing moss and are not even a viable treatment solution. You would have to install them in a special way and put so many on the roof that it makes your roof look unattractive. Zinc shingles work better than zinc strips but still cannot inhibit moss growth. They would have to be installed every 2 to 4 feet to be effective. Most people would not even consider it because it would make their roof look unattractive.

The US Department of Agriculture has strict regulations about the amount of zinc sulfate and the benefits to its use with regards to moss. If you have your moss treated, you must make sure the company has the proper license to perform the work.


Call Cedar Roofs NW for total roof service in:
Oregon:
Portland, Lake Oswego, West Linn, Beaverton, Tigard, Tualatin, Sherwood, Wilsonville, Gresham, Oregon City, and Clackamas Washington:
Vancouver.