Help needed with leaking replacement windows.

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kelchm
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Joined: Fri Nov 08, 2019 1:50 pm

Help needed with leaking replacement windows.

#1 Post by kelchm » Fri Nov 08, 2019 2:12 pm

I purchased a house last year which had replacement vinyl windows (mostly Appleby System) installed ~5 years. They were installed directly into the existing Andersen frames and then capped on the exterior with bent aluminum flashing (example).

This hasn't been a problem on the windows with deep overhangs, but I've had consistent problems with leaks from the top of windows where there is no roof overhang. It seems like the root of the problem is that the flashing that was installed is simply 'C' shaped, does not extend behind the vertical wood siding at all and relies entirely on caulk caulk between the bottom of the siding and the flashing to prevent leaks. I've re-caulked a few of the windows that have leaked consistently, but I know this is a band-aid fix at best and the leaks will eventually return.

The house does not have any house wrap, but the majority of the exterior is wrapped with 1" EPS foam with 3/4" furring strips creating an air gap behind the siding. I've had a difficult time finding information on best practices with flashing replacement windows with this type of construction. I want to make sure I have a very solid understanding of how this needs to be fixed before I start talking to any contractors.

Can anyone provide any advice or guidance on how to approach fixing this?

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toddinmn
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Re: Help needed with leaking replacement windows.

#2 Post by toddinmn » Fri Nov 08, 2019 3:48 pm

I’d try to get a drip cap behind the insulation , the furring strips if possible. Sealing it the sheathing would be best. Was the insulation taped? Do you know if they spray foamed the Windows in? Does it have casing on the exterior, what type of siding , maybe some pics.

kelchm
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Re: Help needed with leaking replacement windows.

#3 Post by kelchm » Thu Nov 14, 2019 2:56 pm

Todd,

Here are some more photos. This first two photos are of a window which does leak in torrential rain (I haven't re-caulked this one yet) while the second two photos give you an idea of how the capping was actually installed. It's hard to tell from the photos, but the cap does not extend behind the siding at at -- it simply sits below the siding and the gap was caulked.

The house is entirely cedar siding. The majority of the house has no sheathing, just 1" EPS foam on the outside of the framing, 1x3 furring strips and then the cedar siding. The windows were not spray foamed -- just strips of fiberglass stuffed between the new window and the existing frame.

I hadn't considered adding a drip cap over the existing flashing. That seems like a pretty economical approach but I'm not sure how to go about actually attaching the drip cap to the foam. I suppose even just getting it behind the siding is better than what's there now.

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HomeSealed
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Re: Help needed with leaking replacement windows.

#4 Post by HomeSealed » Thu Nov 14, 2019 3:33 pm

Todd's comments sound on point.

I would not say that the root of the problem is the capping, UNLESS the window installers capped over the drip cap/head flashing. This does happen on occasion and shame on them if that was the case. If not, they simply did their best without digging into this hornet's nest. The problem in that case would be the lack of head flashing, and Todd's solution of adding it would be correct. Most guys would add that flashing and tape it to the face of the foam, assuming that there is no housewrap. If it were my home and I were going through the trouble, I'd actually get that flashing up behind the foam to make it bullet proof. I've had to do that in cases before where the tape let loose or tore... You really want to create a system of positive lapping where should any caulk or adhesive would fail, the seams all face down. Face taping the flashing to the sheathing goes against that.

The other option of course is to simply use high grade caulk and keep up on it, which is assuming that no water is infiltrating the opening in that gap behind the siding.
www.homesealed.com

tru_blue
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Re: Help needed with leaking replacement windows.

#5 Post by tru_blue » Fri Nov 15, 2019 12:48 pm

Water will always get behind whatever siding you use, be it wood, vinyl, stucco, even brick. The intent is for the water to run down the sheathing's exterior (or the air gap between the sheathing and siding material) and weep out harmlessly at the bottom. If you don't have functioning flashing against that sheathing on your home you can expect problems.

I tell my guys that pocket replacement windows into existing window frames are pretty much always fine except when there is a water leak involved at the top of the window. That's because if that problem is occurring, there is usually a leak between the existing window frame and the sheathing. Putting in a replacement window in a leaky frame doesn't solve the problem, so in those cases we suggest a full frame replacement. Either that or the source of the leak has to be addressed before doing a pocket replacement. In your case the windows have already been in place for a number of years so it's a moot point. I'm curious - how do you know that the old frames are from Andersen? Did they have a wood exterior or a clad exterior? If they're the REALLY old Andersen sliders from the 1940s through 1960-ish the frames were made really different from anything anybody makes nowadays. They actually had a ~4 inch section of "sheathing" preattached between the wood window frame and the wood brickmould. If they were "newer" clad units they would have had a nailing flange.

Todd and Homesealed are spot on. Caulk won't solve the issue. At a minimum you'll need to seal flashing up against the EPS foam. Better yet if you get the flashing behind the foam. I'm attaching a diagram that isn't quite like your situation, but it is somewhat applicable as it shows flashing against foam.
Image

jorgeday
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Re: Help needed with leaking replacement windows.

#6 Post by jorgeday » Tue Nov 19, 2019 9:33 pm

toddinmn wrote:
Fri Nov 08, 2019 3:48 pm
I’d try to get a drip cap behind the insulation , the furring strips if possible. Sealing it the sheathing would be best. Was the insulation taped? Do you know if they spray foamed the Windows in? Does it have casing on the exterior, what type of siding , maybe some pics. google street view
How are they held in place?Is it bonded by the caulking or just a tight it in the opening?I don't want to damage the frame...I notices the the water is coming in between the window and the rubber seal so I may have to remove the window and re-seat it too.Any tips ...

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TheWindowNerd
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Re: Help needed with leaking replacement windows.

#7 Post by TheWindowNerd » Thu Nov 21, 2019 11:20 am

Nailed, adhesive, pressure fit, and or gravity.

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toddinmn
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Re: Help needed with leaking replacement windows.

#8 Post by toddinmn » Thu Nov 21, 2019 7:04 pm

Preferably nailed and flashing tape.always easier said then done. Nails to sheathing and flashed to sheathing.

kelchm
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Re: Help needed with leaking replacement windows.

#9 Post by kelchm » Mon Jun 01, 2020 11:24 am

tru_blue wrote:
Fri Nov 15, 2019 12:48 pm
I'm curious - how do you know that the old frames are from Andersen? Did they have a wood exterior or a clad exterior? If they're the REALLY old Andersen sliders from the 1940s through 1960-ish the frames were made really different from anything anybody makes nowadays. They actually had a ~4 inch section of "sheathing" preattached between the wood window frame and the wood brickmould. If they were "newer" clad units they would have had a nailing flange.
The house was built in the late 70s. I guess I can't know with 100% certainty, but I'm confident that the original windows were Andersen because there is one original casement window (all wood, no cladding) still installed in an unfinished attic space which is Andersen branded (photos). On windows where there is no interior trim (unfinished basement) or areas where I've pulled the interior trim the original outer jambs all match the jamb of that remaining Andersen window.
tru_blue wrote:
Fri Nov 15, 2019 12:48 pm
Todd and Homesealed are spot on. Caulk won't solve the issue. At a minimum you'll need to seal flashing up against the EPS foam. Better yet if you get the flashing behind the foam. I'm attaching a diagram that isn't quite like your situation, but it is somewhat applicable as it shows flashing against foam.
Completely agreed with caulk not being a correct or permanent fix, but it has helped in the mean time while I work on coming up with a permanent solution.

What I'm trying to work out is an economically viable way to get flashing behind the siding and positively affixed to the EPS foam (or behind the foam). Ideally I'd pull all the siding, install house wrap, correctly detail all of the windows and reinstall / replace the siding as needed. Unfortunately this gets astronomically expensive very quickly on a house this size.

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