Sometimes the leak is where two sheets of metal overlap. This is called a seam. Water can crawl between them. First, check if the seam is actually closed. You might just need to press the top sheet down with your foot (gently!) to flatten it.
If it’s still loose, you can install a new screw right along the overlap. Drill it through both layers. Then cover that screw (and the whole seam area) with more sealant. Spread it like you’re buttering a slice of bread, about an inch wide.
Pro tip: Don’t be shy with the sealant. You can always wipe off extra, but you can’t add water-tightness after the fact. Be generous. It’s cheaper than a new ceiling.
How to Fix a Leaking Metal Roof | Causes and Solutions
The Flashings: Where Magic Meets Trouble
Flashing is the metal piece that goes around your chimney, vent pipe, or where the wall meets the roof. These are leak magnets. Look for cracks in the caulk where the flashing hits the roof.
If you see a gap, clean the old crumbly caulk out with a putty knife. Yes, it’s boring work. But do it. Then apply a fresh, thick bead of sealant right where the flashing touches the corrugated metal. Smooth it into the creases of the corrugation so water has no path to sneak under.
For vent pipes, check the rubber boot around the pipe. If it’s cracked like an old shoe, you need to replace the whole boot. That’s a job for a pro if you’re not comfortable, but it is doable with a little sweat equity.
