How many layers of shingles does your roof have?
The number of shingles required for your roof often depends on your location. (Photo courtesy of Russell Hiner)
Whether you want to enhance your existing roof or start fresh with a new one, it's important to consider how many shingle layers you should apply to the roof for the appropriate coverage. Some homeowners might assume that the more layers of shingles you add to the roof, the more protection the roof will provide. Although this is true to an extent, adding more than two layers requires a permit in some states and for some types of projects because it could pose a few threats to your safety.
If you live in an area where heavy weather conditions are prevalent, such as rain storms, hurricanes and snow storms, adding more shingle layers to your roof is especially important to prevent your roof from wearing down too quickly. Since replacing an old or damaged roof can be a costly endeavor, it's also in your favor to try the more economically-friendly alternative of adding more shingle layers instead of installing a whole new roof.
Determining which roofs call for layered shingles is a variable based on many different factors and circumstances. However, as a general rule, you should not add extra shingle layers to your roof if it already has two shingle layers. If you have two layers of shingles that are worn out, a good alternative would be to remove those layers and replace them with two new ones, as opposed to adding on a third layer. Fortunately, shingles have a fairly long lifespan, which means they won't require complete replacement very often.
Although layering shingles has mostly positive results, you should make sure to thoroughly examine your old shingles for any damage before you begin the process. If your old shingles are curling, this is a sign that they should be replaced instead of just layered over. New shingles will not lay flat over curling shingles. If your old shingles show no signs of damage or wear, you are usually safe to continue the project.
Too many layers of shingles can be dangerous for the roof since it may not be able to sustain the added weight. Additionally, multiple shingle layers can trap moisture within that area, which can cause premature wood rot. Since the project involves several important considerations, it's crucial that you consult a professional contractor about your concerns before beginning to add layers of shingles to your roof.