Window Gaps

[wordly]

How much of a gap, between the window and wall is acceptable during an install? Also how should the gap be sealed and finished?

Thanks

[InfoSponge]

Are you talking about the gap to the wall studs inside the wall, to the interior trim/sheetrock, or something else?

[wordly]

The gap between the window and where it screws into. Is it suppose to be very tight (no light visible) or is it ok to have a small gap, insulate it, and caulk it? I understand that openings are never going to be perfect.

[XSleeper]

It depends what type of install is being done. On retrofits, where a replacement window is going inside an existing window jamb, you will usually see a 1/8" gap on the sides of the window, and perhaps 1/4" on the top. If the window does not have foam tape wrap, some installers will insulate that gap with either fiberglass or a low-expanding window and door foam. Depending on how the windows were measured, there could be a 1/4-3/8" gap per side. Personally, I prefer smaller gaps so that the existing trim can be reused without any problems.

If your windows have a nailing flange and are going into a rough opening, it's likely that the gaps will be significantly larger- perhaps 1/2" on all sides of the window. In that sort of an install, I prefer a gap of that size so that the perimeter of the window can be shimmed and insulated (low-expansion latex foam). If there is a tiny gap, you can't insulate it very well, which isn't good. All you can do is caulk it, which provides an interior air seal. The outside is also obviously caulked, but air can pass through the jamb, framing, etc so insulating around the frame of the window is usually preferred wherever possible.

[bungalo]

It depends what type of install is being done. On retrofits, where a replacement window is going inside an existing window jamb, you will usually see a 1/8" gap on the sides of the window, and perhaps 1/4" on the top. If the window does not have foam tape wrap, some installers will insulate that gap with either fiberglass or a low-expanding window and door foam. Depending on how the windows were measured, there could be a 1/4-3/8" gap per side. Personally, I prefer smaller gaps so that the existing trim can be reused without any problems.

dang, my replacement units are sized with a 3/4" top gap, which the company said is standard. they come with a "head expander" to fill that gap, but in hindsight I guess i would've ordered it tighter up top. dunno why they size them tight (1/8") on the sides, but loose on top.