DIY Home Improvement Forum banner

Insulating bay window.

8K views 6 replies 3 participants last post by  Clutchcargo 
#1 ·
I installed an Andersen bay window in the early fall and now that it's frigid in the northeast, I find the window drafty. I've great stuffed around all the windows and that has helped a lot but I've still got a draft from between the two windows at the 45 degree angle. How can I get insulation between these two windows? It's still untrimmed so should I just drill a few holes between the windows at the crack and start filling with great stuff?
Thanks
 
#2 ·
How did you finish the underside of the window?
Andersen should have cables that run through the casing at that point and help hold up the window.If the bottom of the window is left exposed the wind will blow up through this cable hole into the casing chamber.
 
#3 · (Edited)
The cable system is a story in itself. In short, it didn't work so I had a couple of brackets made to support the window. I insulated the bottom of the window with 2" foam and some more great stuff so that it would form around the brackets.
The draft is definitely coming from the vertical seam between the two windows. If I shine a flashlight to see into the crack, I see what looks like 1/4" of foam and a wide open cavity. It wasn't that noticeable but now that it's single digits outside, you can definitely feel the cold spot
 
#4 ·
Yep,those cable systems are a bit of a problem.
If your confident that the bottom holes for the cable are plugged and you have decent insulation in the roof area,(filled those cable holes also)spray a little non expandable foam in between the window casings and caulk the back of the trim pieces before they're nailed on.
 
#5 · (Edited)
I was hoping that you were going to say that there is a hidden plate that pops off so that the void can be insulated. This is reminiscent of replacement windows where the old weight bays were left uninsulated.
The roof is stuffed with pink and sealed extremely well so I know that's not the problem. I guess I'll drill 2 or 3 holes to get the straw into the void and start filling. Thanks.
 
#6 ·
Im not completely familiar with anderson, however most bays have removeable mullions at those angles. I would stuff it with some fiberglass if you can. I NEVER use "great stuff" style spray in any capacity on window installs not because it doesnt insulate well, but it makes hell out of any future service of the window.
 
#7 ·
I found the install guide and I see that if I remove the clips inside the joining posts can be removed outside. If I assembled this myself it seems like a no-brainer to fill it with insulation before assembly. There is 1/2" of foam though installed by Andesen.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top