[1QWK96GT]

Good morning everyone!

I recently decided to do replacement windows in my home. I did use Home Depot for measurements and I used those measurements to order replacement windows. On the width of the windows I am noticing they have no gap between them and the old windows frame for insulation. I don’t necessarily like the idea of relying on caulk on the blind stops to the window frame (even though I did use high grade OSI stuff). Anyone have any suggestions for insulation when these windows don’t even leave 1/8” for a spray foam straw or packed insulation? Or am I being to paranoid about caulk failure? I want these things air tight as possible. Any help or suggestions is appreciated!

Thanks,

 

[Nealtw]

You should have 1/4" but that is often used up just setting windows level in a slanted opening.The amount of insulation in there will have little to no effect. But blocking air movement from the house is what you are after.

 

[chandler48]

And using OSI Quad, you won't have to worry about sealant failure.

 

[Windows on Wash]

If the gap is tight, you can just caulk it. The most important thing, as mentioned by Neal, is making sure there is no air movement.

 

[1QWK96GT]

https://photos.app.goo.gl/K5U7Unn39jsU7an56

 

[1QWK96GT]

Thanks guys!! That makes me feel better!

Above is a link to a photo showing what I was talking about.

 

[chandler48]

Is that a double hung window? Slider? It is not installed right, IMO. Can we see the whole window?

 

[1QWK96GT]

Yes double hung window.

 

[Nealtw]

Yes double hung window.

If you want better insulation when you trim that window start with 1/2" or 3/4" foam board against the rough frame and the window.

 

[1QWK96GT]

https://photos.app.goo.gl/1DAj614ymo8RS9c4A

 

[chandler48]

OK, I'll backtrack. The window is fine. It is unusual to have lifts, but you obviously have quality windows. Seal it well.

 

[carpdad]

For very small gap, you can still stuff some insulation in with thin trowel or even metal ruler or apply some caulk to the stop before you put the window against it. DAP canned foam may be bit more costly but it will have zero effect on the window frame and good for air seal. DAP may cost too much if you fill the whole 2x4 gap but you can look for longer tube that will fit the nozzle and apply only the outer face. It expands so test and about 1" final bead should be enough to air seal.
It looks like windows are installed already? How are the sashes moving? Too loose or tight feel? If too loose feel, you may be able to fix it with some shims on the the side.