For alternate courses, which of the following describes how joints should relate to each other?

For alternate courses, which of the following describes how joints should relate to each other?

• A. There should be no direct alignment
• B. Sidelap must be 1-1/2 inches
• C. Joints may align on the same course
• D. Joints must align on every other course

Answer: (A)

Alternate courses are laid with their joints offset so they don’t line up from one row to the next. This keeps a continuous vertical seam from forming, which helps prevent leaks and improves wind resistance by distributing loads more evenly. The description that there should be no direct alignment captures this practice. The other options either suggest joints lining up between courses or focus on different measurements, which don’t describe how joints should relate across courses.

Alternate courses are laid with their joints offset so they don’t line up from one row to the next. This keeps a continuous vertical seam from forming, which helps prevent leaks and improves wind resistance by distributing loads more evenly. The description that there should be no direct alignment captures this practice. The other options either suggest joints lining up between courses or focus on different measurements, which don’t describe how joints should relate across courses.