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Window weight insulation

Have seen that problem. Low expansion foam or carefully cut rigid insulation work well.


  • David Hohengasser
    David Hohengasser Member Posts: 52
    Window weight insulation

    This is not really a heating question, but your expertise has my steam system now running the way it should. I am having replacment vinyl windows installed. Normally they insert expanding foam into the old window weight cavities. My contractor said he stopped using the foam because it expands and the pressure forces the sides out against the replacement window. Any thoughts on this? I want to insulate the cavities.
  • Lurker_2
    Lurker_2 Member Posts: 123
    Don't they sell insulation specifically for this purpose?

    You can buy flexible, low-pressure expansion foam for that purpose under the ubiquitous "Great Stuff" label. I don't know if it is safe for installing windows or not (though it claims to be safe for such applications), but when it cures, it's nice and squishy.

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