Sooner or later, every roof needs to be replaced, usually due to the long-term effects of weathering. If a residential roof is more than 20 years old, it is a prime candidate for replacement. Here are some signs that you need a new roof:
– On the ground, walk around your home with binoculars and inspect your roof for cracked, curled or missing shingles, as well as any excessive loss of the protective mineral granules. DO NOT CLIMB ON THE ROOF; walking on the roof is dangerous and can damage your roof.
– In your attic, take a flashlight and look at the underside of the roof deck and rafters for any stains or wet spots indicating water leaks.
Asphalt shingles can often be applied directly over existing roofs without tearing off the old roof. However, new shingles cannot be properly applied over hard or brittle materials, uneven surfaces for nailing or roof decks with warped, rotted or unsound support that should first be replaced or repaired.
Some local ordinances forbid re-roofing over two or more layers of shingles. If a home already has been shingled several times, it is important to first determine if the roof deck can support another layer of shingles before undertaking any re-roofing project.