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Help deciding on proper insulation for 2x4 Remodel in NC -Elevation 4k

Help deciding on proper insulation for 2x4 Remodel in NC -Elevation 4k

Old 05-25-21, 02:45 PM
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Help deciding on proper insulation for 2x4 Remodel in NC -Elevation 4k

My wife and I bought our dream vacation home: It is a wood frame ranch style home built in 1985 that is undergoing a complete renovation down to the 2x4 studs. The home is located in Highlands, NC (technically a rain forest with 90" of rain last year) with an elevation of 4,000 at the top of a mountain. In a normal situation, we would use spray foam (I forget if it would be open or closed cell) and be done.

However, there is a caveat. I have a lung disease (Cystic Fibrosis) and have respiratory sensitivity to some items. There are repeated stories about people having reactions to spray foam and having to vacate the house permanently. Given my health, we are terrified that our dream home could become uninhabitable for us and we would have to sell after a 1 year renovation.

The builder has proposed a solution of Flash & Batt but has never done that on 2x4 and is concerned about the effectiveness. The alternative is spray foam.

What can/should we do? How do we determine a path forward?

We have to make the decision soon.

Thanks in advance
Old 05-25-21, 03:47 PM
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When I converted a third floor unfinished attic to a bedroom suite in 1986 I was concerned that fiberglass batts in the 2x4 framing would not be sufficient. The solution was to install the fiberglass and then 1.5 or 2 inch (I forget which thickness was used) rigid foam board insulation on the inside before the wall board (3 inch drywall screws). Outlet boxes had mud ring extensions installed. Rigid foam board does not outgas the way some spray foam does. Also spray foam has been improved since then so the problem may not be as serious as it was. In any case the foam board insulation is an alternative.

One problem that I did encounter was that a wall mounted light fixture (not mounted on or hard wired in a box) that uses touch technology for switching did not work correctly. I think the mounting screw penetrating the foil facing interfered with the electronics of the touch switching. I mounted the fixture on a wooden plate isolating the mounting screws from the foil and it works fine.
Old 05-25-21, 04:34 PM
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Are you going for LEED certification or super efficiency? Is there a reason you're gravitating towards foam? Why not go with traditional fiberglass?

You must be on the top or close to the top at that altitude down there. We have relatives that live on a ski mountain near Boone. It's amazing in winter how the elevation and side of the mountain affect the weather and road conditions.
Old 05-25-21, 05:13 PM
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Have you looked into cellulose, have had that in the last two homes, it was no where near as expensive as foam but much better than fiberglass which I will never use again!
2john02458 voted this post useful.
Old 05-25-21, 06:21 PM
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I had neither considered traditional fiberglass or cellulose. The builder had narrowed it to the Flash & Batt concept or Spray Foam (which is what he normally does). To be honest, I am a little clueless which is why I am seeking input so I don't make a bad decision.

Sounds lame but true.

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