Roofing over an existing roof: money saver or bad idea?

by robbinsroofinginc on March 8, 2012

Installing a new roof is an expensive proposition, and it’s normal to want to save money on the project. However, adding another layer of shingles over an existing one is never a good idea. It won’t save much in the short run, and it may cost you dearly in just a few years.

The first thing you should understand is that the biggest expense of a roof replacement comes from the materials that will be used. Labor is the next biggest expense. The cost of the tear-off isn’t as high as you might think.

Another problem with leaving the existing roof in place is the weight. Asphalt shingles are heavy, and your walls and roof structure may not be able to handle the additional weight of a second layer. Asphalt shingles need to lay flat, especially the updated architectural choices. When the shingles are installed over a bumpy surface, like existing shingles, they won’t adhere to each other properly. They will be prone to wind damage, leaving you with higher maintenance and repair bills.

The shingles assume the shape of the surface beneath them. Installing them on a smooth, clean roof results in smooth, clean, even lines. Adding a new layer of shingles over an existing one results in a roof that looks lumpy and uneven.

Rotted sections of a roof deck cannot be properly assessed and repaired without removing the old shingles. If you have experienced a leak in the roof, or are concerned about the areas where flashing may be damaged, the best choice is to do a full tear-off and install new shingles on a smooth roof. This will help ensure that you do not experience a leaky roof in the near future.

Another issue is that water has a habit of traveling. The entry point in a damaged roof rarely lines up with the resulting water stain inside. Experienced roofers know that the best way to be sure that all problems are corrected is to remove the old roofing surface, make the necessary repairs, and start with a clean slate. Whether you have chosen asphalt, clay, or metal for your roof, investing in this step will help ensure that your home stays dry.

Robbins Roofing, Inc., is a highly experienced roofing contractor in the Oklahoma City and Dallas area. Visit us on Facebook or Twitter today to discover the different roofing materials we work with, and how we can help you transform your home.

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