Multiple Layer Roofs

We recommend a polypropylene scrim reinforced underlayment made up of multiple layers.

Multiple layer roofs.

This underlayment layer should be of the highest quality. If the roof is designed to last a lifetime why would anyone want anything but the best. Decking most often made out of plywood this roof layer is installed over the framing in a typical roof install. As a listing specialist i am encouraging a roof replacement on our listings that have multiple layers.

Most building codes allow up to two layers of organic or fiberglass asphalt shingles. Now that roofs are in the spotlight more and more buyer s representatives are asking for a full roof replacement up front in a contract written on a home with multiple layers of roofing. For example towns in climates with heavy hailstorm activity or significant ice dam problems may not allow multiple roofing layers. But contractors who spoke with angie s list say best practices call for stripping the roof down to the wood deck to inspect it before installing a new roof.

This is especially true if you ve overlayed your new shingles on top of warped shingles. Most cities and towns allow a maximum of two layers of shingles says chad muth president of muth company roofing in westerville ohio. Adding a second layer could compromise the structure of your roof. Your three layer roof is definitely a potential structural concern and homeowners insurance companies might consider three layers of roof shingles.

When it s time to replace your roof there are several factors that might lead your roofing professional to recommend adding shingles on top of your existing. It provides structure by tying the trusses and joists together. Benefits of adding multiple shingle layers. Often there is a problem with the first layer of shingles that was not apparent.

One reason some homes have multiple layers of shingles is a homeowner either could not or would not pay to have the original layer of shingles removed after a hail claim. This type of underlayment is critical to a quality roof installation. While simply adding a second or third layer of shingles cost less than replacing the roof my advice to clients is to always have the roof replaced regardless of how long. A re roof might not look good on an inspection report.

Having multiple layers of shingles is going to make your roof hotter because the heat gets trapped between the layers which could mean premature aging of the shingles. According to the international existing building code homes can be re roofed one time by applying a second layer of roof shingles over the existing one but after that application begins to wear. That limit pertains to roofs with up to a 4 12 pitch. Many roof decks were designed to handle only one layer of shingles.

You can usually see the underside of plywood decking from the attic. Now you just have to decide whether to remove the existing roof shingles or recover the roof. Local codes might not allow re roofing.