4:12 is _______ than one ply of 15 pound felt?

The answer is indeed that 4:12, which represents a slope ratio in roofing (specifically a rise of 4 units for every 12 units of run), indicates a greater amount of drainage capacity compared to one ply of 15-pound felt. In roofing terminology, the slope of 4:12 is considered a moderately sloped roof, which allows for better water runoff compared to a flat surface or lesser slopes.

One ply of 15-pound felt is a specific type of underlayment material that is often used in roofing, but it does not directly compare in terms of slope or drainage capability. The key point is that the underlayment material serves as a protective measure beneath roofing materials, but does not contribute to the slope or drainage performance. Therefore, saying that 4:12 is greater in terms of performance and capacity for drainage makes sense in this context.

It’s important to understand that relative comparisons of roofing metrics often focus on drainage and performance capabilities, and in this case, the slope of 4:12 enhances those characteristics more than merely having one ply of 15-pound felt.