What should be the minimum slope of a roof for effective drainage?

The minimum slope of a roof for effective drainage is typically between 2% and 4%. This slope range ensures that water can flow off the roof efficiently, preventing pooling and potential water damage or leaks. A slope of 2% allows for a gentle but effective incline, while a slope approaching 4% can facilitate rapid drainage, especially during heavy rain.

Roofs with insufficient slope, such as those with 0% to 1%, may not allow for adequate water runoff, leading to accumulation and increasing the risk of leaks or damage to roof materials over time. Higher slopes, such as those in the 5% to 10% range, are suitable for specific design purposes but are generally not required for standard residential or commercial roofing, and can sometimes pose challenges in construction and accessibility. Therefore, the range of 2% to 4% strikes a balance between effective drainage and practicality in roofing construction.