Where is a roof most likely to develop leaks?

Where is a roof most likely to develop leaks?

• A. eave
• B. field
• C. valley
• D. roof jack

Answer: (C)

Water flows with gravity and tends to find the path of least resistance. The valley, where two roof planes intersect, forms a trough that concentrates water as it runs down the roof. That concentration means any flaw in the valley flashing, or in the shingles around the intersection, can allow water to seep through more readily than on a flat field of the roof. Valleys are also prone to movement from temperature changes and are common spots for ice damming in cold climates, which can lift or tear flashing and widen gaps. To prevent leaks, valley flashing must be continuous and properly integrated with the shingles, and joints need to be sealed where different materials meet. While leaks can occur at eaves, the broad roof field, or around vent flashings, the valley is the most likely spot for water to penetrate because it actively channels water through a concentrated area and presents multiple potential failure points.

Water flows with gravity and tends to find the path of least resistance. The valley, where two roof planes intersect, forms a trough that concentrates water as it runs down the roof. That concentration means any flaw in the valley flashing, or in the shingles around the intersection, can allow water to seep through more readily than on a flat field of the roof. Valleys are also prone to movement from temperature changes and are common spots for ice damming in cold climates, which can lift or tear flashing and widen gaps. To prevent leaks, valley flashing must be continuous and properly integrated with the shingles, and joints need to be sealed where different materials meet. While leaks can occur at eaves, the broad roof field, or around vent flashings, the valley is the most likely spot for water to penetrate because it actively channels water through a concentrated area and presents multiple potential failure points.