Install Flashing Around a Bay Window
LESLIE: Leaky windows are on John’s mind out of Virginia who listens to The Money Pit on JFK. Tell us about the window.
JOHN: The window is a bay window on the side of the house. There’s aluminum siding on that side. So, from the two corners of the bay window, you’ve actually got – if you want to call them – two – a hip on each side. And I looked at it – I’m a carpenter, if you want to call me that. I’m embarrassed to admit that I’m needing help on this, but (laughter) …
LESLIE: That’s OK.
TOM: That’s OK, John. (laughing)
JOHN: Thank you. Where the center part of the roof of the bay is hitting the siding, there’s flashing going up under the siding and there’s flashing coming down on top of the shingles. There’s no cocking (ph) along the bottom of the flashing. On the side – on either side of the hips, the flashing actually goes under the shingles and behind the siding. So – and there’s water damage on the inside on the top of the bay window. And I cannot for the life of me figure out, unless it’s getting up under that – it’s copper flashing – unless it’s getting up under there somehow. At the house from the outside, you can see the flashing coming down on top of the shingle on the center part. But on either side, that flashing is under the shingles.
TOM: Sounds to me like the flashing isn’t done correctly. Is it possible to remove the siding?
JOHN: Yeah. I was hoping I wouldn’t have to do that (inaudible).
TOM: Well, you and I both know that if you want to get to the bottom of this, you’re going to have to start from scratch.
LESLIE: See what’s in it.
JOHN: Yeah, I guess. See, I was trying to save this guy some money. He’s a nice guy and …
TOM: Well, I mean anything you do on top of this, if there’s a mechanically wrong method to the way that flashing is installed, first of all you’re not going to know it until you get the siding off and it’s going to probably become painfully obvious to all of you. But once you pull that, the one thing that I like to recommend is when you’re going to flash a roof like that, that you put mastic behind the flashing and sort of on top of the flashing and then give it some of that reinforced fiberglass mesh over that seal and then you side on top of that. So now you have a mastic that’s sealing the flashing to the wall originally and then you’re going to side and tarpaper over that so it really gives you a tight seal where the water can’t push up and over and back in. You follow me?
JOHN: Yes sir, I do.
TOM: And I think that once you pull the siding off – and if you want to not do the whole thing, then maybe you just start on the sides because it sounds like where that’s leaking – you’re going to find out that that assembly, that the steps are not done correctly.
You know, if you don’t start at the bottom with flashing and go step by step by step and you put the flashing in, then you put the shingle in, then you put the flashing in, and then you put the shingle in, and if that pattern is broken on the way up to the top of that hip section of the bay window …
LESLIE: You’re just creating a space for the water to get into.
TOM: Exactly. It’s going to find it every single time.
LESLIE: And it’s better to go deep into the repair than just patch it with, say, tar or something like that.
TOM: Yep, exactly. So I think that’s probably the best approach, John. That’s what’s going to give you the best long term solution. And you know, I appreciate the fact that you’re trying to save your customer money on this. And I’m sure that the customer appreciates that as well. But if it turns out that you do, you know, a patch job repair, the thing leaks again in six months, he’s not going to be happy with you; he’s going to have more damage to the house.
JOHN: He’s a Prince William County cop, too, (laughing) so I don’t want any tickets that I don’t deserve.
TOM: Exactly, you know? Do it once, do it right and get one of those PBA cards, OK? Because it could get you out of a ticket if you do a good job. (laughter)
John, thanks so much for calling us at 1-888-MONEY-PIT.