What is the function of side lap in roofing?

The function of side lap in roofing is to create a seal against water. Side laps refer to the overlapping areas of adjacent roofing materials, such as shingles or metal panels. This overlap is critical in ensuring that water does not penetrate through the seams between the roofing pieces. By having the side lap designed properly, it allows for rainwater to flow off the roof rather than pooling at seams, thereby significantly reducing the risk of leaks.

The efficacy of this sealing mechanism is particularly important in regions that experience heavy rainfall or snowfall, as it enhances the overall waterproofing of the roof system. In addition to water protection, effective side laps also play a role in managing wind uplift pressures, as they help to keep the roofing materials securely in place. Understanding this function is essential for achieving a long-lasting and watertight roofing assembly.