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Insulate between floors/stories from attic

Hello everyone and thank you very, very much for your assistance.

I am the owner of a circa 1993 2 story cape cod style home in northern Alabama. Even with all the knee walls and gables, the wall insulation is pretty good. Attic floor insulation over temperature controlled space is also pretty good. I do have one major problem, the space between the stories of the house from the attic. I can sit in the attic and look at the knee wall insulation. Then I lean down to look under the floor of the second story/above the attic of the first story and I can see all the way through the house, nary a scrap of insulation there! That means even with the insulation in the walls, I only have the small R value of the drywall & flooring for those spaces. How to do I go about remedying this problem? I was thinking about calling in the spray foam guys and have them spray a "plug" at each end. This would effectively turn the space into temperature controlled spaces. Are there any issues with this approach?

I also thought about buying some nice fiberglass batts and folding them over and pushing them in the spaces to make my own plugs, but the spray foam air barrier characteristics seem important (especially as I cannot insulate across the whole span of the house, just at the ends).

Many Thanks,
Drafty & Uninsulated in Alabama

Re: Insulate between floors/stories from attic

Yes --- having spray foam applied to the area under the knee wall will work ---- forget the rolled up batt insulation since it won't stop air movement.

Or --- purchase some sheets or rigid foam insulation and cut sections to fit into the cavities. Use canned spray foam and apply a bead around the perimeter of those panels to adhere and seal them.

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