making decisions about roof replacements

making decisions about roof replacements

Causes Of Granule Loss From Asphalt Shingles

by Lorraine Fisher

The function of mineral granules on asphalt shingles is more than cosmetic. Apart from giving the shingles (and hence your roof) their color, the granules protect the roof from ultraviolet radiation damage and also increases its fire protection ability. This is why it's important to know why and how your asphalt shingles may lose its granules. Here are four causes of granule loss:

Roof Traffic

Mechanical abrasions can dislodge asphalt granules. In fact, many granules are lost during installation or roof repair work as roofers and their tools cause scratches on the roof. Fortunately, this isn't something to worry about because the granule loss is minimal and stops when the roof traffic stops. However, it shows that you should minimize roof traffic to protect your shingles.


There are two main causes of asphalt blistering. One of them is trapped moisture, which occurs during the manufacturing process. After the shingles are installed on the roof, the moisture expands due to heating and blistering occurs. Shingle manufacturers refer to this form of blistering as a cosmetic defect.

Your roof may also experience blistering if it is poorly ventilated. If the heated air cannot escape, then the attic heats up, the heat spreads to the overlying shingles, and blistering occurs.


Weather elements such as moisture and sunlight may not damage your roof overnight, but the cumulative effect will be noticeable after some time. For example, ultraviolet radiation from the sun degrades the chemicals holding the asphalt together. The degradation makes it easy for other forces to remove granules from the shingles. For example, such loosened granules may be swept off the roof by overhanging tree limbs or get carried away by rainwater. Granule loss due to aging tends to occur uniformly across the roof.


Storms, especially hailstorms, can cause significant granule loss. Serious storms, characterized by big hailstones and lasting for a long time, can cause noticeable granule loss. You can actually see bald spots on the roof or granules on the ground after some storms. The loss of granules may be even more severe if the shingles are aged, and the chemicals in the asphalt have started deteriorating.

Shingles that have lost granules are fragile. They crack easily, which increases the risk of water seeping into the underlayment. This is why significant granule loss means that you should start planning how to re-roof your house. A serious delay may result in water damage that may require more expensive repairs, in addition to the new roof.

For more information on roofing, contact a company like GBS Enterprises Roofing.


About Me

making decisions about roof replacements

Is the roof on your home ready for replacement? If so, do you know what type of roofing you are going to have installed to replace it? Will you have the existing roof removed, or just have the home re-roofed? You will face several decisions while you work to replace the roof on your home. Scroll through my site to find a great list that can help you decide what product and method of installation will be best for your home. Hopefully, the information provided will take some of the confusion and stress out of this big, important home improvement project.