Commercial Building Inspector B2Roof Ceiling ConstructionEasy
An inspector is reviewing the plans for a new commercial building with a membrane roof. The plans indicate the roof is designed with a slope of 1/4 inch per foot. What is the minimum required design slope for roof drains in a membrane roof system, according to the IBC?
- A1/2 inch per foot
- B1/4 inch per foot
- C1 inch per foot
- D1/8 inch per foot
Show answer & explanationAnswer & explanation
Correct answer: B. 1/4 inch per foot
The International Building Code (IBC) specifies minimum slopes for roof drainage to ensure proper water runoff and prevent ponding. For membrane roofs, a minimum slope of 1/4 inch per foot is required.
Why the other options are wrong
- A. While a greater slope is beneficial, it is not the minimum required by code.
- C. This is a very steep slope for a typical membrane roof and is not the minimum code requirement.
- D. This slope is generally considered insufficient for effective drainage on membrane roofs.
Membrane Roof Minimum Slope
The minimum design slope for a membrane roof system, typically 1/4 inch per foot, to ensure adequate drainage and prevent water ponding.
- Prevents water accumulation.
- Critical for roof longevity.
- Specified by building codes.
Memory trick: Sloping roofs keep water flowing, preventing puddles from growing.