Roofing
Hiring a Contractor - Pros & Cons
How to Repair Shingle Roofs
Repairing your shingle roof is not complicated. Look for damaged, curled, or missing shingles. At every place where two surfaces meet and around every chimney or vent, look for breaks in the flashing or caulking or for gaps in the lines of roof cement.
Some of the tools you'll need for replacing shingles are a pry bar, scraper, replacement shingles, a utility knife, roofing nails, hammer and asphalt roof cement.
If you find evidence of shingle problems, repairs are fairly simple. Curled-back shingles can be reattached with asphalt roof cement or compound in tubes for use with a caulking gun. In warm weather, you can easily straighten out the curled shingle. In cold weather, shingles become very brittle and must be softened before they can be flattened out.
To reattach the shingle, apply roof cement generously to the bottom; a good dollop of cement at each corner is usually enough. Press the shingle firmly into place.
If shingles are torn, rotten, or missing, they should be replaced with new ones. Any shingle that lifts right off the roof with no effort is rotten and should be replaced.
If you find a large area of rotten shingles, you may need a whole new roof. If so, consider calling a professional roofer.
To replace damaged shingles:
Step 1: To remove damaged shingle, lift edges of surrounding shingles, and carefully remove nails with pry bar. Slide out old shingle. If there's loose or brittle roof cement left under it, scrape opening clean. When shingles are blown off by a storm, remove any protruding nails left in roof. Nails that don't stick up can be left in place.
Step 2: To make it easier to slide new shingle into place, slightly round its back corners with sharp utility knife.
Step 3: Slide new shingle into gap, with its front edge aligned with shingles on each side and its back edge under shingles in row above it.
Step 4: Lift corners of overlapping shingles and fasten top of new shingle with galvanized roofing nails driven through each corner. Cover nail heads with roof cement, then smooth down overlapping shingle edges.
(source: www.howstuffworks.com)