Best Way to Stop Windows that Leak

LESLIE: Georgia in Georgia is on the line with a question about windows that leak. What can we do for you?

GEORGIA: Well, I have a problem with windows that are leaking every time it rains.

TOM: OK.

GEORGIA: I have water intrusion and bug intrusion coming in in the corners, at the window sill. And I was wondering what you might be able to suggest.

TOM: So you have water and bugs coming into the corner of the window sills?

GEORGIA: Yes.

TOM: Talk to me about – what kind of siding do you have on your house? Is it vinyl or aluminum or is it wood? What have you got?

GEORGIA: I have vinyl siding and I was originally told that I’d have to buy new siding after it was taken down and the windows could be repaired. But then, I found somebody who could remove the vinyl siding but – and put it back. But he didn’t know how to fix the windows that leak.

TOM: Well, if you have windows that leak, they have to be sealed from the outside. And that would probably best be done underneath the siding. There’s a couple of different types of flashing that they use that would make this transition. One is the head flashing, which basically goes under the siding and over the top of the window. And the second is the flashing that basically seals the sides of the window. And it’s particularly important, in your case, because it sounds like you may be getting driving rain in.

Now, this presumes that the water is coming in around the window. You can prove that by taking a garden hose and just strategically sort of holding it alongside the window and see if you can make it leak.

The other place it could be coming in is between the window panes themselves – or not the window panes but the window sashes themselves. And if that’s the case, then the windows that leak are defective and probably needs to be replaced. And again, you could do it the same way but now you want to move the house to the inside portions of the window as opposed to the outside, around the trim of the window.

But if you do both of those tests, you ought to be able to narrow this down. But it’s clearly an issue – most likely an issue – with the flashing not being right under that siding and around that window.