Preserving your home through roof care

For many of us, the purchase of a home is the largest single investment we'll ever make. Thus, we should do everything we can to preserve it. One of the best ways is to be sure the roof is in good shape and properly maintained.

Roofs leak for a two primary reasons: poor maintenance and deterioration due to old age. How long should your roof last? The American Society of Home Inspectors provides the following estimates for the life expectancy of different roofing materials: Asphalt shingles 15-30 years; Wood shakes-shingles 10-40 years; Clay-cement tiles 20+ years; Slate 30-100 years; and metal roofs 15-40+ years.

The life of your roof depends upon a variety of factors including local conditions, the quality of materials and installation, and ongoing care and maintenance.

According to the National Roofing Contractors Association (NRCA), an industry trade association, heat and ultraviolet rays produced by the sun have the most devastating effect upon a roof, regardless of materials. The sun will cause the material to expand and contract, fade, cup, curl, crack and deteriorate.

Rain isn't an ally either. Water will naturally take the path of least resistance. For this reason, one minor roof leak can result in extensive damage in various locations throughout a home. Aside from the obvious water-stained sagging ceiling, prolonged leakage will likely result in rot to framing members in the roof, ceiling, walls and floor.

High winds can lift the edges of shingles and force wind-driven rain and debris beneath them. Extremely high winds can tear random shingles from the roof, leaving the roof spotty or even bare in some locations. Properly anchored shingles will minimize this damage.

Snow, ice and hail, also, do their share to shorten the roof's life. Melting snow often will freeze over the roof's overhang where the surface is cooler creating an "ice dam" which blocks drainage to the gutter, and results in water backing up under the roofing material. Gutters and downspouts can also freeze, preventing proper drainage. Eave heating devices can prevent ice buildup. Check with your local hardware store or home center for the one that will work best for you.

Mildew, moss and liken can accumulate on roofing materials if they remain damp as a result of poor drainage or little sunlight. Once it grows, moss holds moisture to the roof surface causing rot or poor watershed. One of the best ways to rid the roof of moss and fungus is with a good power washing. (This may be best left to a roofing contractor or roof care professional.) Another way is to apply a solution of one quart of liquid chlorine bleach in a gallon of hot water to the affected areas, using a stiff nylon brush.