Foam spray insulation

For those self-installers
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eddieE
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Foam spray insulation

#1 Post by eddieE » Thu Aug 18, 2016 6:38 pm

Quick question...do you use low expansion spray foam between the NEW vinyl window and the old frame? How big does the gap have to be before you use the foam?

I keep reading about installers that don't use foam between the new window and the old frame. They instead stuff fiberglass in the gap, which I would think is useless.

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Windows on Washington
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Re: Foam spray insulation

#2 Post by Windows on Washington » Fri Aug 19, 2016 5:25 am

Gap can be pretty darn small if you have the right tip on the spray foam gun.

Definitely need to use a gun and not a stray if you are working with a tight gap.

Guy
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Re: Foam spray insulation

#3 Post by Guy » Thu Sep 01, 2016 12:33 pm

WOW nailed it! If you've never used canned foam before....don't start on your house. The store bought can does not offer much control. You have to learn how to spray and let it expand. The theory is to not have the foam expand out from the gap and onto the window, casing, floor, and window coverings. It's a nightmare believe me!! We use commercial guns with micro tips. You can foam down to 1/16" to two inch gaps easily. But you need a gun that can be turned down enough to control a slower flow. Otherwise bring a lot of drop cloths and paper towels. If it's not expanding much just mist it with a spray bottle of water. This will expedite the expansion process. If you get it all over you'll need Acetone Thinner to clean it up. Scary stuff!
There shouldn't be any installer out there who believes in the stuff in method. It's been proven over and over again that it's a waste of money and it leaks like mad. Plus most installation guidelines require expansion foam. Do it once and do it right! Good Luck!!!

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