So, how's your roof? You don't know? Most of us don't know what's happening with our roofs because we never actually climb up and look at them. Of course, "out-of-sight, out-of-mind" is not a good roof maintenance strategy. Your roof should be examined for defects annually or at least every other year. A properly maintained roof will last longer and be less susceptible to leaks. Roofs exposed to the damaging effects of sun, wind, and rain undergo periodic minor damage that, when left unrepaired, can result in leaks and substantial damage to the building. Slow hidden leaks can create ideal conditions for rot, mold, and fungus to grow in attics and wall framing.

The best prevention is to hire a specialty inspector or reputable roofer to examine your roof every year or two. Relatively simple repairs can prevent leaks and significantly extend roof life. We don't recommend that any person go up on a roof unless he or she knows and follows proper safety procedures. Even if you don't do the work yourself, it's important to know how proper repairs are done, and a basic knowledge of roof repair techniques will help you better negotiate with your roofer.

Who made your roof? The brand name and style of roofing material used is especially important with composition or asphalt shingles, concrete tile, fiber cement shingles, and metal roofs. These roofs consist primarily of a manufactured product that is assembled and installed on site. You can often search for the manufacturer online and find specific repair procedures. Other roofing materials, such as wood shakes, wood shingles, and built-up, or tar and gravel, depend less on the specific manufacturer and more on associations.

Repair methods are different for each roofing material. Fibered roofing cement, or mastic, is the most common patching compound used on asphalt composition shingles and built-up roofing. Mastic is an inexpensive asphalt-based patching material, which adheres easily to metal, stucco and asphalt roofing. Mastic can be used to patch damaged shingles or to seal roof-to-wall connections and plumbing vent penetrations. Mastic deteriorates from sun exposure, and new applications are necessary every few years. New mastic should be allowed to dry for a few weeks and then painted for protection from the sun and for better appearance. Mastic will not stick to wood and should not be used to patch wood roofs or connections to wood siding. Modified bitumen roofing can be damaged by the solvent in some mastics, and only special patching materials specified by the roofing manufacturer should be used with these and other polymer or synthetic rubber roofing materials.

Shake roofs have a layer of felt or tar paper under each row to serve as a waterproofing barrier. Every year a small amount of the shake surface is worn away by the sun and weather. Holes eventually develop in the shakes, exposing the felt to damage from the sun. Damaged shakes can be repaired by inserting a thin wood shingle, composition shingle, or piece of sheet metal beneath them to protect the exposed felt from the sun. In general, it is best to avoid using nails when repairing a wood roof, as this can cause leakage. Power washing a wood roof using water under high pressure can cause significant damage and is not advisable unless done with extreme care by a skilled operator.

With slate or tile roofing, the general rule has traditionally been to replace any broken slates or tiles. Special adhesives are now available that can effectively repair broken tiles. Any loose tiles should be secured with wire, nails, or special adhesives available for this purpose. The tile manufacturer should be consulted for repair recommendations.

Tar and gravel, or built-up roofs, also need regular maintenance. The perimeters of these low slope roofs are usually left uncovered with gravel and are exposed to damage from the sun. All areas where the asphalt is exposed should be coated with an aluminized asphalt emulsion or one of the new rubberized white roof coatings. We often find the central portions of gravel-covered built-up roofs to be in good condition, while the raised edges with no gravel protection show substantial sun damage.

What if your roof can't be repaired? Most roofing materials will last 15 to 30 years before needing replacement depending on the type and weather exposure. Roof surfaces facing the south or west often wear out sooner because they have longer exposure to the primary cause of roof wear-the sun. When your roof needs replacement will depend on several factors, including your tolerance for occasional leaks and periodic roof repairs. Most roofs, with careful maintenance, can be kept functional for many years beyond their rated life spans.