I’d like to build a 4′ tall conditioned crawlspace for a new home here in the Southeast, but I’m not sure what the best material to use is. Obviously cost is important as well as energy effeciency since the rest of the house will be built using SIPS (Structural Insulated Panels. Are ICF’s the way to go? I was really interested in Superior Wall but their 4′ wall is only R-5. How about good old fashioned concrete blocks? Any thoughts?
Edited 4/1/2005 11:58 am ET by mlawrence
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I've never buit a new one, but have retro-ed a few. The houses I've done have had block foundations, over which we've applied a 6-mil poly vapor barrier which is then covered by foil/bubble insulation (Reflectix or Astro-E). My understanding is some inspectors make you use foil-faced foam over block if it's new construction.
R-5 might be fine. R-value is only one consideration. What's the greatest difference in temperature you expect between inside and out? Thirty degrees? Maybe forty? Up here in the north, insulation is designed for differences of seventy and eighty degrees, and I think the national codes are designed with the north in mind. Since the insulation in Surperior Walls isn't subject to convective loss the way that fiberglass is, you can expect it to perform better than, well, better than you might expect.
How do you detail ICFs in the south so that they can be inspected for termite tubes?
Andy
Andy Engel
Senior editor, Fine Woodworking magazine
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