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Foam vs Sealant - which is better around windows?

Foam vs Sealant - which is better around windows?


Old 11-08-13, 10:12 PM
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Foam vs Sealant - which is better around windows?

Looking for some opinions on which is better around windows. Expanding foam (ex: product called "Great Stuff") or sealant?
Old 11-09-13, 05:27 AM
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Around doors and windows, you will want to use "minimally expanding" foam meant for that purpose. The regular great stuff will expand too much and will bow the framing of doors and windows.
Old 11-09-13, 06:25 AM
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around windows
If you are referring to insulating the space in the wall (between the window and the rough opening) that is a good place for the minimally expanding foam that Larry mentioned. If the gap is about 3/8" wide or larger, I would use Great Stuff windows and doors- the blue can... not the red can. If the gap is 3/8" or smaller, I like to use Dap latex window and door foam. Mainly because foam likes to come back out and get on you and the trim when the gap is small, and the Great Stuff makes more of a mess.

If you are referring to sealing the outside perimeter of a window, either inside or outside... and the area will be seen (not covered by any trim) and/or will need to be painted, then that is DEFINITELY not a place for foam, but is a place to use sealant. If the gap is large, stuff the appropriate size of foam backer rod (caulk saver) into the gap until it is maybe 1/8" below the surface, then caulk and tool as needed. The type of caulk that works best changes with what the two surfaces are that are being joined together, and sometimes with the size of the gaps being caulked.

Window installation will always perform better if the window jambs have been insulated with foam, and then the edges of the window are caulked. You should do both, not one over the other.

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