Question 17

The minimum slope for modified bitumen built-up roofs for new construction is 1/4 inch per foot.

A slope of 1/4 inch per foot is the standard minimum required for modified bitumen built-up roofs in new construction. This slope is essential to ensure proper drainage and prevent water accumulation on the roof surface.

A) 1/8 inch per foot.

A slope of 1/8 inch per foot is insufficient for modified bitumen built-up roofs. This minimal slope could lead to water pooling, which can compromise the integrity of the roofing materials and lead to leaks or structural damage over time.

B) 1/4 inch per foot.

This option is correct as it represents the minimum slope required for modified bitumen built-up roofs. A slope of 1/4 inch per foot facilitates effective drainage, reducing the risk of water-related issues and extending the lifespan of the roofing system.

C) 3/8 inch per foot.

While a slope of 3/8 inch per foot is adequate and exceeds the minimum requirement, it is not the minimum slope specified for modified bitumen built-up roofs. Therefore, while it offers better drainage, it does not address the question of the minimum slope necessary.

D) 1/2 inch per foot.

A slope of 1/2 inch per foot is higher than the required minimum and would effectively promote drainage. However, it is not the minimum slope mandated for modified bitumen built-up roofs, making it an incorrect choice in this context.

Conclusion

The minimum slope of 1/4 inch per foot is crucial for modified bitumen built-up roofs as it ensures adequate drainage and prevents water accumulation. Other options either fall below this requirement or exceed it without addressing the question of the minimum needed. Thus, option B is definitively correct, aligning with industry standards for roofing practices.