Which phrase best restates the rule for alternate courses?

Which phrase best restates the rule for alternate courses?

• A. There should be no direct alignment of joints
• B. Alternate courses must have a 1-1/2 inch sidelap
• C. Adjacent courses require no sidelap
• D. All joints align on alternate courses

Answer: (A)

In roofing, joints between shingles are staggered from one course to the next so a single seam doesn’t run straight up the roof. This offset helps prevent a continuous weak line that water or wind could exploit. Saying there should be no direct alignment of joints captures that idea precisely: the joints in alternate courses must not line up with those in the courses above or below. This practice distributes joints across the roof, improving weather resistance and durability. The other ideas either introduce a specific sidelap amount, imply no overlap between adjacent courses, or claim joints must align, all of which don’t reflect the purpose of staggering joints.

In roofing, joints between shingles are staggered from one course to the next so a single seam doesn’t run straight up the roof. This offset helps prevent a continuous weak line that water or wind could exploit. Saying there should be no direct alignment of joints captures that idea precisely: the joints in alternate courses must not line up with those in the courses above or below. This practice distributes joints across the roof, improving weather resistance and durability. The other ideas either introduce a specific sidelap amount, imply no overlap between adjacent courses, or claim joints must align, all of which don’t reflect the purpose of staggering joints.