What is the minimum number of layers required for asphalt shingles?

What is the minimum number of layers required for asphalt shingles?

• A. One layer
• B. Two layers
• C. Three layers
• D. Four layers

Answer: (B)

Two layers is the typical minimum you end up with when installing asphalt shingles in a reroofing situation. You lay a new layer over the existing roof to provide a solid, continuous base for nailing and to help meet wind-resistance expectations. Building practices and many codes limit the total number of asphalt-shingle layers to two, so if there’s already one layer under you, adding another brings you to the minimum two layers. Installing just one layer would usually be a brand-new installation on a bare deck; in a common reroof scenario, the finish is two layers. Adding three or more layers is generally not allowed due to extra weight and potential performance problems.

Two layers is the typical minimum you end up with when installing asphalt shingles in a reroofing situation. You lay a new layer over the existing roof to provide a solid, continuous base for nailing and to help meet wind-resistance expectations. Building practices and many codes limit the total number of asphalt-shingle layers to two, so if there’s already one layer under you, adding another brings you to the minimum two layers. Installing just one layer would usually be a brand-new installation on a bare deck; in a common reroof scenario, the finish is two layers. Adding three or more layers is generally not allowed due to extra weight and potential performance problems.