Insulating Floor; Old House

Old 07-17-03, 01:53 PM
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Insulating Floor; Old House

I need ideas on how to insulate the hardwood floor (approx. 30 inches above ground). Our home is in the very humid deep south and we have to find ways to barrier against moisture as much as possible.
Old 07-17-03, 05:48 PM
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Both schools agree that a moisture barrier should be put over the ground, usually sheet plastic at least 6 mil thick. The ground is a major source for humidity in homes, regardless of the climate.

One school advocates insulating the floor of the home. This prohibits both the heat and humidity from getting into the home. This application I would agree to if it was in a cold climate area and outside humidity did not play a major factor.

The other school, which I support in your situation, advocates insulating the inside of the walls of the crawl space and not ventilate the crawl space. I base my opinion on where the majority of the humidity is coming from and all heat has humidity in it. In your case it is apparent that it is from the outside and you want to keep it outside the structure.
Old 07-25-03, 01:04 PM
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I also live in a house on piers.
When I insulated my floors, I first applied a 6 mil plastic on the ground, I later came back and spread about 4" of sand on top of the plastic. Some people use pea gravel.
My crawlspace is open, and I didn't want the wind to disturb the
plastic as it was difficult enough to put down.
Between the floor joists I used an unfaced batt insulation.
However be sure to install the batts in contact with your flooring, because condensation can form ( yes, even with the plastic on the ground) between the insulation and the flooring if there are ANY gaps. This can cause your floor to develop 'soft spots', or more accurately stated will over time cause the flooring to deteriorate.
I found some batts had a stiffinig added (can't remember what it was called) that would hold it in place. I didn't want to EVER work under my house again, so I used chicken wire and cut it to fit between the joists and used heavy duty staples to attach it to
the insides of the joists.
Some people use strapping, but again I was worried about condensation, so the chicken wire will hold it in place all over and not just where the strapping material was used.
This was about 5 years ago and so far no problems, evey so often I check to make sure that nothing has disturbed the chicken wire, because we have a lot of armadillos and possums around here. But I guess the dogs run them off.

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