Roofers Washington DC
Takoma Park, MD
Specialty Contractor, Commercial Contractor
Angie's List, CertainTeed Select Shingle Roofer, Certified Contractors Network (CCN), EnergyStar, GAF ELK Master Elite, HeatSpring Learning Institute, Home & Garden Television, Inc. 5000, National Roofing Contractors Association, Qualified Remodeler Top 500
Silver Spring, MD
QUESTION: During a recent trip to my attic, I found evidence that I have a leak in my roof. Can I fix a leaking asphalt roof myself?
ANSWER:With a little time and patience, most roof leaks can be tracked down and patched. The first step is assessing the entire roof before you begin patching. A roof truly in need of re-shingling will thwart most attempts at patch jobs. Typically, asphalt roof shingles at the end of their lives will curl up and/or bubble. Also, the granules on a defunct shingle's surface will be nearly gone, and pieces of shingle or entire shingles will be missing. In a case like that, it's best to re-shingle the entire roof. However, if your roof shingles are in decent shape, remember that roof leaks don't always end in the attic at the spot where they begin on the exterior roof's surface. Sometimes a leak begins 10 or 12 feet from where it ends.
Still, the most notorious locations for roof leaks are around a chimney, in dormer and gable valleys, and in corners where a sloping roof abuts a vertical wall. At the chimney, leaks often originate where the sheets of lead flashing that come out of the chimney meet the roof. These sheets fold down the side of the chimney and are woven under the nearby shingles. In between the individual layers of lead flashing, water often penetrates and works its way under the roof material.
The best solution here is pumping plastic roof cement (a tar-like substance) in between the layers of flashing. Plastic roof cement can be purchased in tubes sized for an ordinary caulking gun, which is the most convenient tool for applying the goop without a lot of mess. In roof valleys, the search for a leak source and the proper fix is a bit trickier. Most valley leaks don't show up until the roof carries a snow load or debris in the valley stacks up deep enough to hold water.
If the leak appears when these conditions are in place, then it's time to tear up at least one set of valley shingles and see what's underneath. At the very least, there should be extra layers of roofing felt under the valley shingles. Better yet, metal flashing or bituminous roofing underlayment should be under the shingles. But most often, there's no extra waterproofing in the valley, and that's why you have the leak in the first place. When replacing small areas of asphalt shingles, try to work during warm (70° F or so) and overcast days. This makes removing the bad shingles easier and results in less damage to the good shingles nearby. Gently roll back the good shingles and remove both the underlying nails and bad shingles as you go, working from the top of the valley down. Remove shingles at least three feet away from the valley. Before installing new shingles, be sure you have proper flashing or the bituminous ice and water shield firmly in the valley.
This same approach is used when leaks are located near the point at which a vertical wall meets a sloping roof. The only difference is some wall siding must be removed to install new flashing or a water shield both on the roof surface and at least 18 inches up the abutting wall.