Fix Flashing Around the Chimney to Stop Leaks
LESLIE: Shirley in Nebraska finds The Money Pit on KFOR. And you’ve got a leaky roof. Tell us what you see.
SHIRLEY: We’ve got a house that has a fireplace and it leaks right where the fireplace … right where the chimney is. I don’t know if it’s flashing we need to put around it or …
TOM: Yeah, generally it is. When you get a leak right above a fireplace, it’s usually the intersection between the roof and the chimney itself. Now, if it’s done properly, you’re going to have two pieces of flashing there. You’re going to have a base flashing and then a counter flashing. The base flashing goes under the roof shingles and up along the side of the chimney. The counter flashing goes in the mortar joint of the chimney and then folds over the base flashing.
And the reason it’s done that way is because the chimney and the roof are going to expand and contract at different rates. And this, actually, is sort of like a joint that allows the flashing to move and, this way, you’re not going to have it loosen up over the years. And what happens is, typically, sometimes that does loosen up and then the piece falls out. And if that’s the case, you’re going to get a leak in there.
You also want to take a look and see if anyone’s tried to repair it before. Sometimes people will try to repair flashing with a roofing cement. But it’s generally a really bad idea – especially around a chimney – because all that movement will cause it to open up and leak again. But it’s definitely going to be the flashing and, fortunately, that’s pretty easy to fix. It should just be a service call from a roofer.
Shirley, thanks so much for calling us at 1-888-MONEY-PIT.