Shingles cut from durable cedar and similar woods, commonly called shake roof shingles, are attractive and relatively long lasting compared to other materials. However, applying the wrong coating or failing to coat the roof at all can result in a short lived roof that costs a lot to repair and replace. Take care of your roof by choosing the right roof coating and avoiding the wrong types.
Right: UV Blocking Stains
Want to change the color of your roof or protect it from the wear and tear effects of daily sun exposure? Choose a stain designed specifically for use on cedar shake roofing. Products for other types of wood or cedar siding installed vertically on walls may or may not work for your roof, so stick with stains that are tested and approved for this specific use. Stains are preferred to other types of coatings because they absorb into the surface of the wood instead of creating a barrier over the surface.
Wrong: Thick Sealants
When it comes to protecting wood from water, most of the time a thick sealant is better than a thin stain or other coating. However, cedar shingles are naturally rot and water resistant, as long as they can dry out normally after every afternoon rain shower. Coating the shingle with an overly thick sealant results in trapped moisture that eventually causes the cedar to rot despite its resistance. Don't use a sealant advertised as being waterproof on wood roof shingles since they need to breathe to evaporate out trapped moisture, but water resistant coatings may be fine if they're tested specifically with cedar products.
Right: Moss Control Chemicals
Aside from roof coatings designed to prevent weathering or change the color of shake shingles, you can also use herbicidal sprays and coatings that kill existing moss and algae growth while preventing future damage. Moss and algae grow tiny roots into the rough surface of the cedar shake shingles, slowly wedging the wood apart and trapping moisture where it creates rot. Keep in mind that you need to protect the space around your home when applying these kinds of chemicals to avoid damage to the soil and plants around the drip edges of the roof.
Finally, avoid the urge to paint your cedar shake roof, no matter what it looks like. Even the toughest exterior paints can't handle the direct sun and regular rain fall of a roof, and the paint will simply accelerate the decay of the wood instead of protecting it by trapping moisture.
For more information and details, talk with professional roofers, such as those at Surface Shield Protective Coatings.