Left untreated, they will weather to a natural gray, or they can be painted or stained. Cedar shakes and shingles are highly wind and hail resistant roofing choices, and when properly treated have excellent fire resistance. Shingles cut from the heartwood of trees that are naturally decay resistant to decay, such as western red cedar, will last longer and age better than many man-made materials.
Proper fasteners and installation are a must. Because shingles are wood, they will occasionally become wet. Consult a local professional for the appropriate backing materials in your area. Nails or staples must be rust resistant. Use stainless steel of hot-dipped galvanized nails of the appropriate length. Avoid using electroplated galvanized or unfinished nails. They will rust, and at least stain the siding. At worst, they can weaken and lead to expensive repairs. Always remove debris, such as branches, pine needles, and leaves. If they are left to accumulate, they will impede or trap run-off rainwater that then can result in leaks. Clean them by using a stiff broom or brush. Also, remove debris from the gaps between the individual shingles.
Mold and mildew can be removed with a solution of 3 ounces trisodium phosphate (TSP), 1 ounce of liquid laundry detergent, 1 quart of 5 percent sodium hychlorite (household bleach), and 3 quarts of warm water. Apply the solution undiluted and scrub the surface with a soft brush. When clean, rinse thoroughly with fresh water. Avoid getting the mix on surrounding plants; rinse the plants thoroughly with fresh water if you do. Use a 10 percent solution of zinc sulfate to control moss growth. The moss absorbs the zinc oxide and eventually can be swept away. Another remedy is to use a mixture of one part household bleach to four parts water to kill the moss.