The minimum overlap of vertical joints of felt or paper, which is applied to exterior walls, as a weather resistant barrier, is _________ inches.

The minimum overlap of vertical joints of felt or paper, which is applied to exterior walls, as a weather resistant barrier, is _________ inches.

• A. Not more than 8
• B. Not less than 2
• C. Not less than 6
• D. Not more than 4

Answer: (C)

Water resistant barriers must have their seams overlapped so moisture can’t wick through the joints. For vertical joints on exterior walls, the overlap must be at least six inches. This amount ensures the upper sheet covers the lower one adequately, keeping the barrier continuous as water runs down the wall. Less than six inches (like 2 or 4 inches) wouldn’t provide enough protection, and although some products allow different overlaps, the minimum required by the standard is six inches. Follow the manufacturer’s instructions and any local code, since specific products may have variations.

Water resistant barriers must have their seams overlapped so moisture can’t wick through the joints. For vertical joints on exterior walls, the overlap must be at least six inches. This amount ensures the upper sheet covers the lower one adequately, keeping the barrier continuous as water runs down the wall. Less than six inches (like 2 or 4 inches) wouldn’t provide enough protection, and although some products allow different overlaps, the minimum required by the standard is six inches. Follow the manufacturer’s instructions and any local code, since specific products may have variations.