If you’re buying a new house or looking to replace your roof, you may be curious about how many roof shingles your home can have. What’s the acceptable practice, and what’s a warning sign for disaster? Check out this guide from McLean Roofing and Siding to learn about roof shingle layers.

Local Building Code Requirements for Shingle Roofs (2 Layers Max)

Local building codes vary from one location to the next, but most will permit a max of two layers of roof shingles. These rules may also vary based on the types of shingles you have on your roof. Slate shingles are much heavier than asphalt, so one layer is the max your roof can safely support.

Speaking of safety, you also need to take fire safety into consideration. As your roof ages, the shingles become less fire-resistant. Adding a new layer of shingles on top of old, worn shingles could put your home at greater risk for a roof fire. This problem increases considerably with each added layer.

Why Most Roofers Recommend Only One Layer of Shingles

There are many reasons why roofers recommend replacing your existing shingles instead of adding a new layer. For starters, your old roof probably doesn’t provide a great foundation for new roof shingles. The shingles have to be flat with no peeling or cracking, which isn’t common for roofs reaching the end of their lifespan. Read Re-Roofing vs. Roof Replacement for more info.

If you install a second layer over the first, your roofers won’t be able to fully assess the decking and trusses below. They may miss a key issue that could lead to costly repairs in the future. The new roof layer would double the weight of your roof, making any structural compromises that much more dangerous.

Many insurance policies will not cover roof damage for a roof with multiple layers of shingles. Furthermore, many home loan types will not support a house with multiple roof layers. If you’re trying to buy a new house that has two or more layers, the lender may not fund the loan unless the roof is replaced.

What If My Roof Has More Than Two Layers of Shingles?

If your roof has three or more layers of shingles, it’s definitely time to get that evaluated. The roof may be hurting your home more than it’s protecting it. If you need to file an insurance claim in the future, the insurance company will likely deny your claim due to faulty installation. Get a quote for a roof replacement to protect your property well into the future.

McLean Roofing and Siding offers comprehensive roofing services, including new roof installation and roof replacement with cleanup. Contact us at (248) 524-1111 to schedule your free roof evaluation.