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Insulate around Window dilemma

Each of my newly installed windows have a draft. Recently I removed the trim around my windows to investigate how much insulation was installed. I noticed on each window there is a plastic expansion piece which fills the space between the window and house framing. This piece of plastic is placed against the outside vinyl siding. There is no insulation in this area. I would like to know if I should insulate this area with some spray foam. Any recommendations would be appreciated. Thanks.

Re: Insulate around Window dilemma

If you elect to use spray foam use the stuff made for doors and winders, in the blue can. It expands with less pressure than the red or black cans, and thus will not deform the winders making them hard (or in some cases impossible) to operate.

from your description, foam sounds like the way to go.


  1. Prep all the windows at the same time.
  2. Once you start using a can, keep going until its empty.
  3. Keep newspaper handy for the un-expanded foam to drip on.
  4. Keep paint thinner handy to dissolve the un-expanded foam that gets onto things you don't want it on.
  5. Wear old clothes as you will find the foam got stuck on you in places you couldn't see.

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