43. Which of the following roof types is generally NOT used on slopes of less than 2 inches per foot?
Answer: A
Asphalt shingle roofs are generally NOT used on slopes of less than 2 inches per foot.
Asphalt shingle roofs typically require a minimum slope of 2 inches per foot to ensure proper water drainage and to prevent water from pooling, which can lead to leaks and damage.
A) Asphalt shingle.
This option is correct because asphalt shingle roofs are not recommended for slopes less than 2 inches per foot. Their design relies on gravity for water runoff, and insufficient slope can compromise their effectiveness and durability.
B) Asphalt roll roofing material.
Asphalt roll roofing is suitable for low-slope applications and can be used on slopes less than 2 inches per foot. It is specifically designed for such conditions, making this option incorrect in the context of the question.
C) PVC-type membrane.
PVC-type membranes are also appropriate for low slopes, including those less than 2 inches per foot. They are often used in commercial roofing and are designed to provide effective waterproofing in various slope conditions, rendering this option incorrect.
D) Asphalt or coal tar.
Both asphalt and coal tar can be used on low-slope roofs, including those with slopes of less than 2 inches per foot. They are designed to adhere well and provide a waterproof barrier, so this option does not fit the criteria set by the question.
Conclusion
Asphalt shingles are not suitable for slopes of less than 2 inches per foot due to their reliance on adequate drainage to function effectively. In contrast, the other options—asphalt roll roofing, PVC membranes, and asphalt or coal tar—are designed for low-slope applications, making them inappropriate choices for this specific question.