The most difficult part of repairing a roof leak is finding the source of the leak; where and how is the water making its way inside! There are a couple of techniques to help you find the source of the leak: one is nature - find the location on a rainy day or use a hose to simulate the rain! But know where the weak spots are will save you time in locating the leak.
The most common cause of roof leaks are transitional roof areas: chimney, skylights, vents, valleys and dormer areas. Quite often the flashing is not installed correctly. Flashing is sheet metal installed at any transition point on an asphalt shingled roof to prevent leaks. If the flashing is not installed correctly the asphalt shingle roof is vulnerable to leaking.
Another factor in roof leaks with asphalt shingles is the pitch of the roof. Gravity is what keeps the water rolling off the roof. If a roof has a low slope there is more potential for the slow moving water to be blown under the asphalt shingles. And there is always the potential of melting snow on a roof to pool at an ice dam area and be pushed under the asphalt shingles.
Repairing Asphalt Shingle Roof Leaks
Once you identify the source of the leak, repairing a roof leak can really be quite simple. If your roof leak is due to a low slope, you may want to consider applying a clear asphalt shingle roof coating. If you find a hole in the flashing then, you can take a piece of metal flashing and, slide it over a hole and up and under the shingle above. It should fit OK without using an adhesive. But you may want to consider a clear elastomeric roof coating to be sure the surrounding area is sealed.
However, it may be easier and more effective to apply an elastomeric asphalt shingle roof coating over the area that has a problem with the flashing. If you apply a roof coating you can extend the coverage area and seal a larger area at one time. As a preventative measure, you can apply the roof coating to all the transition areas on the asphalt shingle roof and lower the risk of future leaks.
There are several roof coatings that can be applied to stop a roof leak. Roof coatings come in black, clear or basic colors. I prefer using a clear asphalt shingle roof coating, thus eliminating unsightly black patches or mis-matched colors.
When selecting a roof coating, be sure to know how it is applied. Some roof coatings are applied with a trowel and others with a brush, applying with a brush will make the job easier. Another factor with applying a roof coating is the temperature, some roof coatings can not be applied in cold weather! So check temperature restrictions also.
If you have problems with ice dams you may want to use a clear asphalt shingle roof coating around the roof edges where ice dams occur. This will prevent melting snow & ice from being pushed or pooling on the roof shingles.