Metal Roof
Metal Roof

Put a New Cool Metal Roof over Your Old Asphalt Roof

Have you ever wondered if new metal roofing can be put on over your existing asphalt shingle roof? The answer is YES! With the light weight of metal roofing, it's actually a well practiced installation technique with a proven track record for success. Even our experts recommend going this route to save money and time, assist with home insulation issues, and reduce yard mess during the installation process.

There are many important factors to consider when assessing if you can put your new metal roofing over your existing asphalt roof. First, most areas have building codes in effect that restrict residential roofing to two layers maximum. Some areas may have no building code regarding this, but having a structural engineer do some load studies on your home is key.

Second, you want to assess the condition of your old asphalt shingles by looking for roof leaks, rotted lumber and ensuring that the underlying roof sheathing is sound, especially around the roof penetrations, valleys and eaves. Your new metal roof will fasten to the decking, not the old asphalt shingles, and while deterioration of the old shingles will not have a major impact, it is the possible presence of rotted decking that could cause a problem.

Third, there are many attic ventilation options. Choosing the right option will help proper ventilation to avoid the build-up of heat or moisture in the attic. Fourth, be certain that the new metal roofing product you've chosen is approved for the pitch of your existing roof. Lastly, be certain to ask your metal roofing contractor about creating a flat surface. If you don't, you risk the underneath shingles "reading through" the metal as time passes.

Don't let this decision weigh down your concerns – placing a new cool metal roof over your existing asphalt roof can be done and is a preferred method of many contractors. Explore the full world of metal roofing products before making a final decision and keep in mind the many differences in product appearance, metal, finish, warranty, and installation details. Visit the MRA Website to contact a metal roofing contractor near you for more information.


Tom Black
Executive Director
Metal Roofing Alliance

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