Which measurement represents the minimum sidelap between adjacent wood shingle courses?

Which measurement represents the minimum sidelap between adjacent wood shingle courses?

• A. 1-1/2 inches
• B. 1 inch
• C. 3/4 inch
• D. 2 inches

Answer: (A)

The key idea is how much the upper course must cover the seam of the lower course to keep water out and accommodate wood’s movement. For wood shingles, a generous side lap is needed so wind-driven rain can’t sneak under the seams as shingles shrink and expand with moisture and temperature. The standard minimum sidelap that most codes and manufacturers specify is 1-1/2 inches. This amount provides reliable weatherproofing and helps ensure the joints stay covered over time. Smaller laps (like 3/4 inch or 1 inch) can leave vulnerable gaps, while a lap of 2 inches is larger than typically required and wastes material.

The key idea is how much the upper course must cover the seam of the lower course to keep water out and accommodate wood’s movement. For wood shingles, a generous side lap is needed so wind-driven rain can’t sneak under the seams as shingles shrink and expand with moisture and temperature. The standard minimum sidelap that most codes and manufacturers specify is 1-1/2 inches. This amount provides reliable weatherproofing and helps ensure the joints stay covered over time. Smaller laps (like 3/4 inch or 1 inch) can leave vulnerable gaps, while a lap of 2 inches is larger than typically required and wastes material.