What does the term butt edge refer to in roofing?

The term "butt edge" in roofing specifically refers to the lower edge of the shingle tabs. This is the part of the shingle that is exposed and visible once the shingles are installed on the roof. In roofing applications, the butt edge is critical because it plays a significant role in the overall appearance and performance of the roofing system. It is where the shingles overlap, providing a point of material thickness that helps manage water drainage and protect against leaks. Understanding the function of the butt edge is essential for proper installation, as it ensures that shingles are aligned correctly and that they effectively shed water.