Multiple Layer Roofs

Here are the layers of a roof in order of application bottom to top.

Multiple layer roofs.

Your three layer roof is definitely a potential structural concern and homeowners insurance companies might consider three layers of roof shingles. Adding a second layer could compromise the structure of your roof. 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. As a listing specialist i am encouraging a roof replacement on our listings that have multiple layers.

This type of underlayment is critical to a quality roof installation. This is especially true if you ve overlayed your new shingles on top of warped shingles. Two layers is the maximum in most areas but some building codes allow only one. For example towns in climates with heavy hailstorm activity or significant ice dam problems may not allow multiple roofing layers.

We recommend a polypropylene scrim reinforced underlayment made up of multiple layers. Many roof decks were designed to handle only one layer of shingles. A re roof might not look good on an inspection report. 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.

You can usually see the underside of plywood decking from the attic. Benefits of adding multiple shingle 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 underlayment layer should be of the highest quality.

Decking most often made out of plywood this roof layer is installed over the framing in a typical roof install. A second layer of shingles only complicates the job when a roofer is trying to fix a leak. Most building codes allow up to two layers of organic or fiberglass asphalt shingles. Now you just have to decide whether to remove the existing roof shingles or recover the roof.

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. That limit pertains to roofs with up to a 4 12 pitch. Local codes might not allow re roofing. 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.

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. If the roof is designed to last a lifetime why would anyone want anything but the best. Often there is a problem with the first layer of shingles that was not apparent.