Roof sealant and membranes
Most roof leaks are sealant failures around something that goes through the roof.
The short version
- Know the roof type before you seal: EPDM rubber, TPO, or fiberglass. Use sealant that's compatible with it.
- Self-leveling lap sealant goes on flat roof joints. Non-sag sealant goes on vertical edges.
- Clean off dirt and loose old sealant first. New sealant on a dirty surface won't stick.
- Inspect around vents, the AC, antennas, skylights, ladder mounts and the edge trim.
Shop tip
Most manufacturers want roof seams inspected regularly. Customers rarely do it, which is why you see so many leaks.
Try it on a service call
Put the lesson to work on a hands-on troubleshooting case.