Which term describes the horizontal overlap between shingles?

Which term describes the horizontal overlap between shingles?

• A. Shingle butt
• B. Sidelap
• C. Exposure
• D. Toplap

Answer: (B)

Sidelap describes the horizontal overlap between shingles. It’s how much the edge of the upper shingle covers the edge of the shingle below in the same course. This horizontal overlap is key for keeping seams water-tight and helping the roof resist wind uplift. If the sideload is too small, water can penetrate the joints and wind can lift edges; if it’s too large, you waste material and may affect alignment and appearance. Understanding sidelap helps ensure a durable, properly performing roof.

Sidelap describes the horizontal overlap between shingles. It’s how much the edge of the upper shingle covers the edge of the shingle below in the same course. This horizontal overlap is key for keeping seams water-tight and helping the roof resist wind uplift. If the sideload is too small, water can penetrate the joints and wind can lift edges; if it’s too large, you waste material and may affect alignment and appearance. Understanding sidelap helps ensure a durable, properly performing roof.