One of the most common deficiencies I find when inspecting roofs is shingles that are loose or lifting. If wind catches these loose shingles they can peel off the roof or break, leaving the underlayment exposed. This often leads to leaks which can damage the structure. Inspecting the roof often for signs of loose shingles can save a homeowner from costly future repairs.
Anatomy Of A Shingle
Asphalt shingles are compromised of a base mat layer of a woven fiberglass. This base mat gives the shingle is rigidity and structural base. The base mat is then coated in asphalt on both sides. A fine mineral material called back surfacing is applied to the back of the shingle to protect it from damage and keep it from sticking together during transportation. A heavy
layer of colored ceramic coated mineral granules is then applied to the top of the shingle. This layer protects the shingles from UV Rays, hail, and other damage. The last step is to apply a self sealing strip of asphalt on the top of the shingle to bond layers of shingles together and resist uplift from wind. This is covered by a thin layer of plastic which should NOT be removed during installation. Some companies put identifying markers on this tape which is used during the warranty process so removing it can void the warranty.
Dimensional shingles have another partial layer of shingle bonded to the base layer making them have a three dimensional appearance. This makes them thicker, last longer, and hold up to damage better.
Loose/ Lifting Shingles
When I perform a home inspection I always check for loose shingles in multiple areas of the roof. Often loose shingles are not visible just by looking at them. An improperly sealed shingle will allow me to slide my hand underneath without prying upwards. Sometimes I will use a small flat bar but you should not have to force the bar under the shingles.
Many times there will be multiple shingles that are loose in one area. At this time I would recommend a professional be called into repair the roof. It is important to understand how to properly repair the roof so you can check the professionals work, however working on a roof can be dangerous. If you decide to attempt this repair by yourself I would recommend following the information found in OSHA's "Protecting Roof Workers" pamphlet.
The most common reason shingles did not seal is a failure of the tar strip that is designed to resist wind uplift. This could be a manufacturers defect or a defect of the installation, either way the repair is the same and fairly simple if not tedious.
How To Repair Loose/ Lifting Shingles
The repair of undamaged shingles is pretty straight forward. Carefully lift the loose tabs of the shingle and put a bead of roof sealant underneath. The sealant should be placed about 1" to 1-1/2" up from the bottom of the shingle. Be careful not to crack, rip, or damage the shingle when you lift it. Mild weather is the best for working on shingles, not too hot and not too cold. During hot weather walking on the roof can damage the top mineral layer of the shingle. During cold weather the shingles are brittle. A nice overcast 50 to 70 degree day is about perfect for working on shingles. The hardest part of this repair is finding all the loose shingles. This can be a time consuming process. Once you find one shingle you will inevitably find more.
If you find you shingle has been damaged it will have to be removed and replaced with a new shingle. It is important this process is done by a professional as it can be difficult to properly nail and seal the new shingle.
It is important to maintain the various areas of your home and your roof is one of the most important. I believe it is in the best interest of every homeowner to have their home inspected annually to catch problems before they become expensive repairs. A home inspector can help you maintain your home and keep things in tip top shape. For more information about your roof you can read our article "Roofing System- An Overview"
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