Insulation around windows ?

[Cycledude]

Installed all 12 new windows in my 86 years old house. The outside work is mostly done but now I need to finish the inside work, need to insulate the small space around the windows and am wondering about using that spray foam type insulation that comes in aerosol cans , have you ever used the stuff and if you did how do you like it ? Maybe I’d be better off just using regular fiberglass insulation ? Thanks for your help.

 

[duffer]

IMO, fiberglass won't work near as well as the spray foam. The foam expands into minute areas that you can't get fiberglass into without crushing it, which defeats the purpose of the insulation in the first place.

If you use the spray foam, BE SURE to get the low expansion formula made specifically for doors and windows. The regular foam can expand too much and put pressure on your jams and glass potentially.

 

[Doofy]

Use the spray foam that is made for doors and windows. It fills the gaps extremely well and stays pliable and does not expand enough to swell or warp anything. Great stuff!

 

[EddieWalker]

First, make sure it's the foam designed for windows. The other stuff will expand so forcefully that it will bow your windows.

In my opinion, using window foam should be required. Taping the exterior is probably more important, but foam is also very important.

Your biggest enemy is allowing air to get around the windows. If air can get through there, then the heat or cold from outside will get through there too!!!!

 

[Have tractor did travel]

Some of that foam is labeled "sealant" which is what I think of it as being. Other of that foam is labeled "insulating sealant". No R value is given. To me - no specific claim, probably means not much R value. I've been insulating the outside walls of my 102 year old house. Around the windows, where I could push in insulation, I pushed in insulation. Where it seemed nonsensical, I sprayed foam. Spray lightly - it expands, as you don't want the foam pushing the window frames out of plumb. You can always come back later and give it another shot.
After researching the R value of new windows, and storm windows, I decided to keep the original windows (and the money) and just re-glaze, insulate, and caulk. It's worked out well. No drafts. We added interior shutters for its additional insulating value (stagnant air between shutters and windows).
Incidentally, if you are using, say R15 fiberglass, and pack it into the opening, you do not increase R value. You don't lose R value, but there is nothing gained by compressing the insulation.

 

[Diggin It]

If you go with foam, use the stuff marked windows and doors or small gaps and cracks. The regular stuff can expand too much and warp the sides which can cause problems for the windows.

 

[ROUSTABOUT]

I install replacement windows. I still pack insulation around them. After one dose of a bunch of cans that wouldn't spray, I learned a roll of insulation works every time.

 

[AndyMA]

I install replacement windows. I still pack insulation around them. After one dose of a bunch of cans that wouldn't spray, I learned a roll of insulation works every time.

The problem is that doesn't meet the IECC Energy Code which requires foam. Keep n mind that fiberglass insulation has no air sealing properties As others have stated use low expansion window foam, I do energy audits and see windows you can't open with normal foam

 

[ROUSTABOUT]

The problem is that doesn't meet the IECC Energy Code which requires foam. Keep n mind that fiberglass insulation has no air sealing properties As others have stated use low expansion window foam, I do energy audits and see windows you can't open with normal foam

National Fenestration Ratings Council. Does his 86 year old house even have wall insulation? As far as air infiltration, I caulk each side and all the wood completely. I've also built several ICF homes. But, people just can't see it, and want those 2x4's. ICF is phenomenally better.

 

[Cycledude]

National Fenestration Ratings Council. Does his 86 year old house even have wall insulation? As far as air infiltration, I caulk each side and all the wood completely. I've also built several ICF homes. But, people just can't see it, and want those 2x4's. ICF is phenomenally better.

No this house did not originally have insulation inside the walls but about 30 years ago I blew insulation into the walls and ceiling, obviously that doesn’t work very well but it’s better than nothing.