Roofing shingles first line of defense against water

About 80 percent of the roofing shingles in the Atlanta area are some form of asphalt composition shingles. Since water is the No. 1 enemy of our houses and roofing is our first line of defense, it is a good idea to have some understanding of these shingles, how they work and how to maintain them.

The anatomy of a shingle: There are essentially two types of asphalt composition shingles: organic and glass fiber. Organic shingles use paper or felt saturated with asphalt to make them waterproof. A layer of asphalt containing embedded ceramic granules is added as a top coating. Glass fiber shingles have a reinforcing fiberglass mesh base layer. This mesh is coated with asphalt containing mineral fillers to make the shingle waterproof.

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If you’re having a roof replaced, make sure weather conditions are conducive. Some simple repairs can be made by a competent do-it-yourselfer.

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Choosing the right shingle: The advantage to organic shingles is durability. They tend to be heavier, allowing them to resist tearing and uplift in heavy wind better than glass fiber shingles. Glass fiber shingles, however, are lighter and tend to be less expensive. Glass fiber shingles have captured the majority of the markets in the South. Since they perform better in colder weather, organic shingles are often used in Northern climates.

Installation conditions: Asphalt shingles should not be installed in cold weather. Shingles need to seal to the layer below them. If temperatures are too cold, the asphalt seal strip will not melt and the seal will not occur. Asphalt shingles should also not be installed with staples. Use of conventional roofing nails is preferable. Especially in hot climates, proper attic ventilation is important to help extend the life of asphalt shingles and to avoid drastic changes in temperature known as thermal shock.

Do-it-yourself repair: Some simple shingle repairs can be made by a handy homeowner. Please be careful, walking on even a low-sloped roof can be dangerous. Before you begin a repair you should determine whether or not you need to replace the entire roof. To help with this decision, access the shingles on the sunny side of the roof. Grab a corner of a shingle between your thumb and forefinger and bend it slightly. If the shingle tears or breaks instead of flexing, it is likely time for a new roof. Also look for erosion of the colored granules on top of the roofing. If the granules have eroded exposing more of the black asphalt under them or the granules have collected in your gutters, you are likely ready for a new roof.

If you have an isolated, torn or damaged shingle that requires replacement and the rest of your roof is in good shape, you will first need to get a replacement shingle. If you do not have extra shingles, take a piece of the damaged shingle to a reputable building supply store and find the closest match. Using a flat pry bar, carefully separate the damaged shingle from the layer below. Pull out the nails holding the old shingle. Again using the pry bar, loosen the seal of the shingles in the row above. This will allow you to slide the new shingle into place. Once the shingle is in the correct position, nail it near the top so that the shingle row above will cover the nailheads.

Cleaning those stains: Unless you have black shingles on your roof, you will often develop some unsightly stains on the shingles. These stains are most often the result of an algae growth that occurs on the more shaded parts of the roof. There are several ways to remove the algae, ranging from pressure washing to cleaning with bleach solutions, to installation of zinc strips near the top of the roof. During rain, a small amount of zinc oxide will flow down the roof, killing the algae.

If cleaning solutions are used, proper use of the solution is essential. Some bleach solutions will kill plants around the house or even damage the shingles. Pressure washing also requires care since it runs the risk of damaging the shingles. Since all of these remedies require climbing on the roof, it may be best to hire a professional with experience in cleaning shingles.

If your black stains are more universal on the roof, they may be the result of “bleed through.” This is an indication of a defective shingle allowing the black pigment from the asphalt to leach to the surface. If your shingles are less than 5 years old, it may be worth your time to pursue some remedy through the shingle warranty.