[Greenbuilding] passive solar in southern NH

[Lance Collins]

Alan Abrams wrote:


>A variation of George's suggestion cuts the gordonian knot--install the slab
>at grade, or on top of minimal fill, don't worry about the quality of the
>finish, and lay a simple framing system on top.  The frame's then a conduit
>for ductwork--which then can be sheet metal instead of PVC--and provides a
>cavity for insulation--7 or 9 or more inches (working modularly down from
>finish floor to approximate grade)--instead of 2 or 3 inches, as is common
>under slabs.  Still has to be vented for radon of course--which more or less
>precludes the suggestion to place insulation directly over drainage
>rock--but it eliminates the mold prone crawl cavity.  Only other downside is
>that the slab is not available for thermal mass, but life is not perfect,
>no?

I'm a bit puzzled about slab on grade and radon.   Wouldn't the first 
thing placed under the slab be a sheet of plastic as a water barrier 
which would also be a radon barrier?

(It's a purely theoretical question for me as my ground is 400 
million year old mudstone)

Lance
(in Aus)


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