The good news is that leaks on a metal roof can typically be repaired without the need to put in a whole new roof. The key is discovering the culprit causing the leak so that you can schedule the right repair.
1. Fastener Issues
The screws that hold down metal roof panels are the most likely cause of a leak. If driven in too deeply, they warp the panel and allow water in. Leaks also occur if the screws aren't driven in deeply enough. Failure of the sealing gaskets around the screws, or even the aging and corrosion of the fasteners, can also lead to leaks. Replacing the fasteners and seals is the best repair protocol.
2. Failed Flashing
Flashing is used around vents, protruding pipes, chimneys, and other rooftop items. It's typically made of aluminum or another thin metal, although rubberized flashing "boots" are sometimes placed around vent stacks. If the flashing fails or isn't sealed in place properly, then a leak will occur. This leak persists until the issues with the flashing are repaired.
3. Panel Problems
A panel metal roof consists of multiple panels side by side. They are most often installed vertically to allow for water to drain off well. Horizontal panels don't allow for the best drainage so they are more prone to leaks. Panels may also leak if they are not overlapped properly or if any of the panels are warped so that they don't sit flush against the roof decking.
4. Eave Leaks
The eaves are sometimes overlooked, but they are an important part of the roof. If the roof drip edge isn't properly fastened to the eaves, then leaks can occur at this point. Poor guttering as well as gaps or holes in the eaves can also result in leaks along the roof edge. In some cases, water can backflow under the metal panels due to issues at the eaves, so keeping the eaves in good repair is a must if you want to prevent roof leaks.
5. Overlap Seals
The overlap seals are applied where panels overlap. Many metal roofs are standing seam in style, which means these seams are raised so that a good fit can be achieved. Additional silicone seals may also be applied around the standing seams, and silicone seals are a must on other types of panel seams. If the overlap seam sealing fails, then leaks will occur at the overlap. These leaks will persist until the seams are repaired.
Contact a roofing company in your area if your metal roof needs a leak repair.