The restriction on joint alignment primarily applies to which group size of adjacent courses?

The restriction on joint alignment primarily applies to which group size of adjacent courses?

• A. Two
• B. Three
• C. Four
• D. Five

Answer: (B)

The idea being tested is how shingles are staggered to avoid a continuous vertical seam. Joints that line up in consecutive rows can create a weak run that water can track along. The restriction focuses on a block of three adjacent courses: you want to make sure the joints do not align across three successive rows. By offsetting each new course from the one two rows below (typically by at least six inches), you break that three-course alignment and reduce the chance of a long, leak-prone seam. So the group size involved is three adjacent courses.

The idea being tested is how shingles are staggered to avoid a continuous vertical seam. Joints that line up in consecutive rows can create a weak run that water can track along. The restriction focuses on a block of three adjacent courses: you want to make sure the joints do not align across three successive rows. By offsetting each new course from the one two rows below (typically by at least six inches), you break that three-course alignment and reduce the chance of a long, leak-prone seam. So the group size involved is three adjacent courses.