Leaky window needs sealing

3 years ago

Two summers ago, I had rain water seeping into my basement through one of my windows. The wood frame was rotted. So, I replaced all of the pieces and reinstalled the window. All has been well ever since until a few days ago. We had a wicked downpour. The next day, I went into the basement to do laundry and once again discovered rain water seeping in through the bottom of the window. So, it seems it was never sealed properly (the flashing) and in the 2 years since we just hadn't had a rainfall big enough to cause water to seep in. It's hard to tell from the pic but if you look closely you can see the gap between the window opening and the bottom piece of flashing. I've already been in touch with a guy who says he can re-flash it for $150. I'm pretty good with my hands and mechanically inclined. So, I'd like to try and fix the issue myself if it's possible. Does anyone have any suggestions on how I can fix this problem? The gap is not huge. I could probably secure the bottom piece of flashing to the window opening using Tapcon screws and then use silicone sealant on the lip of the bottom piece of flashing. Or, perhaps install something that's weather/rot-resistant between the lip of the bottom piece of flashing and the window opening for it to brace up against and then seal it with silicone. TIA for your advice/ideas.

Featured Answer

PRO

Joseph Corlett, LLC

3 years ago

Forget the TapCons and silicone please. You may be able to flash the sill and jambs withuncured rubber roofing that you'd bond to the window and concrete with splice adhesive. Not pretty, but waterproof.

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Comments (8)

PRO
toddinmn
3 years ago
The water has no where to go . by the loOks of your pics . The grade should start about 6” bel below your window then slope outwards. You may need covers or something more engineered depending how much water you get . Ideally it is engineered where is not reliant upon caulk.
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ci_lantro
3 years ago
From the photo, it looks like a portion of the sidewalk is above the bottom of the window. And an area of damp looks like water was diverted towards the window. If so, that is the problem. I hope that concrete is just a sidewalk and not an entire driveway.
millworkman
3 years ago
Tapcons means holes in the "flashing" which defeats the purpose of flashing (not that flashing is any help in this instance). Caulk is a sealant and a bandaid at best and is not a waterproofing method. Anything other than properly fixing it so the window is not below that concrete is unfortunately basically peeing into the wind.
3onthetree
3 years ago
The concept of sill flashing is working with gravity-falling water. It doesn't do much with water coming from below or to the side of it. Tapcons and caulk on the window sill flashing is just moving the water entrance (for as long as the caulk lasts) to where it can find another way in a little higher or to each side.

A sticky membrane that you would have to create a full pan on the concrete sill, a portion of the concrete jambs, up the window frame jambs, and over the window sill but still wouldn't accomodate a heavy rain that enters the window on top of this membrane. And if you can't get it to slip down vertically in a gap between the slab and wall then I wouldn't consider it a long term success. And and manufacturer's logos all over the black membrane or bright blue color to boot.

I don't see a proper long term solution unless the slab is moved lower, or the window is completely filled in with concrete, or a shorter height window (unit or glass block) is installed and filled in with concrete to raise the sill.
PRO
Windows on Washington Ltd
3 years ago
Exactly what Todd said. No amount of caulk will keep that window dry long term.
Mike Terryberry
Original Author
3 years ago
The concrete slab that everyone is seeing is the old step. I had a deck built over top of it; never bothered to have it removed. I didn't think it would ever be an issue and it wasn't until we had that wicked rain storm.

So, it sounds like I'm going to need a jack hammer to break up the step and remove the pieces; eliminate the source of water that's coming from above the window.
ci_lantro
3 years ago
Great. An easy fix!