How to Repair a Cracked Chimney Area
LESLIE: Now we’ve got Dwayne in Arkansas on the line who’s got a chimney issue. How can we help you?
DWAYNE: I have a rock chimney, probably about 30 years old. It’s about 6 foot by 4 foot on the outside. The inside flue is about 16 inches by 18 inches and the top part is capped off with mortar.
And over the years, that mortar has cracked and somebody has come in and put a – that sealer on top of it, like comes in a gallon or 5-gallon bucket: the black roof sealer? The sealer that often – it’s done a good job but I’m afraid if I have a chimney fire, that stuff might melt and catch on fire and run down and catch the house on fire.
TOM: Well, if you have a chimney fire, Dwayne, you’re going to have a bigger problem than this. Because a chimney fire is super-hot and can burn your whole house down.
TOM: So I wouldn’t worry about it melting. But it wasn’t the best thing to do to the mortar. The right thing to do when you have cracking and chipping of that chimney area is you want to replace the mortar between the liner and the outside of the chimney.
TOM: So that crown has to be broken off and then replaced. And it’s not that big of a deal. You can go up there with a mason’s hammer and break it off in chunks; it’ll come off pretty easily. And then lay in a new crown around it and just make that slope go from the liner out.
If it’s got a couple of cracks in it, you can always caulk it to kind of buy you some time. But replacing that chimney crown is really the easiest thing to do. That plus adding a cap to it – a chimney cap – can help try to keep that water out, as well.
DWAYNE: Yeah. I didn’t know. I have about a ½-inch of the flue still sticking up. I didn’t know if they made some kind of a mortar-type substance that I could put over the top of what’s there.
TOM: I would not put it on top of that asphalt. I would – at this point, I would take all the asphalt out.
See, here’s what’s wrong with the asphalt patch is that the water is going to get under that. And it can still deteriorate the mortar and it can freeze and break and really wreak havoc on that chimney. So I would pull that old stuff out and just replace that chimney crown. It’s not a difficult job to do.
DWAYNE: Alright. I thank you so much.
TOM: You’re welcome, Dwayne. Thanks so much for calling us at 888-MONEY-PIT.