Metal roofs are best known for their longevity and low maintenance. However, just like any other roof system, a metal roof can deteriorate and develop leaks over time. One of the most common sources of metal roof leaks is in the vertical and horizontal seams. This is where the metal panels meet and are held together by clips or fasteners. As normal wear and tear occurs on the roof, along with expansion and contraction, these clips and fasteners can loosen, back out, or fall off, and rust.
Protecting the seams of a metal roof is critical to success, especially for standing seam roof systems. It is recommended to reinforce these seams as the roof ages. Although you can visually see a lifted horizontal seam, it is difficult to tell whether a vertical seam was properly caulked underneath or crimpled during the original installation. Vertical seams can also lack the proper weather seal as the roof ages and moves over time. The practice of simply doing the horizontal seams and ignoring the vertical seams leaves the roof exposed to possible wind-blown rain, creating leaks through the vertical seams.
