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<DIV>Thank you for the comments.</DIV>
<DIV> </DIV>
<DIV>However, I’m not completely sure what you’re saying about insulation.
Removing the insulation provides the opportunity to install what? There is a
very good layer of expensive blow-in insulation under the slab, between the two
floors, and the ceiling downstairs is finished. No way is that insulation coming
out without destroying much of my house. </DIV>
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<DIV>The point on more mass furthering the cycle is good. The slab is already
thicker than my designer planned for the house so already probably is somewhat
retarded.</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=alan@abramsdesignbuild.com
href="mailto:alan@abramsdesignbuild.com">Alan Abrams</A> </DIV>
<DIV><B>Sent:</B> Tuesday, May 14, 2013 5:18 AM</DIV>
<DIV><B>To:</B> <A title=greenbuilding@lists.bioenergylists.org
href="mailto:greenbuilding@lists.bioenergylists.org">Green Building</A> </DIV>
<DIV><B>Subject:</B> Re: [Greenbuilding] Passive solar home--concrete overlay re
thermalmass</DIV></DIV></DIV>
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<DIV>one consideration here is that capping an existing slab in a passive solar
system that presently works "extremely well"-- that is, adding more mass--is not
necessarily more better. more mass will retard the cycle of heating and
cooling, changing the character of thermal comfort. if the cap is thin
enough, maybe it won't be noticed--but this is all quantifiable.</DIV>
<DIV> </DIV>
<DIV>it all raises many questions--about the climate, about the substrate under
the slab, about the details of the envelope of the house--all factors that come
into play in this decision. maybe there is not much insulation under the
slab, so that removing it provides the opportunity to install it. if there
is adequate insulation under the slab, then maybe a thin cap is in order.
</DIV>
<DIV> </DIV>
<DIV>on the subject of thermal mass and heat transfer, I think RT's earlier
reply was definitive. thermal mass is simply a function of density or
specific gravity, and an acrylic admixture and/or thin film of bonding compound
between original and new slabs would neither change the density of the slab or
retard conductive heat exchange between the two in any significant way.</DIV>
<DIV> </DIV>
<DIV>some time ago on this list serve, back in the pleistocene era, IIRC, there
was a discussion on high strength, super thin slabs, akin to ferro-cement boat
hulls--which might have application here. someone with even more time than
I have to waste could look it up. </DIV>
<DIV> </DIV>
<DIV>AA</DIV>
<DIV> </DIV>
<DIV><SPAN style="COLOR: rgb(102,0,0)">Alan Abrams</SPAN><B
style="COLOR: rgb(102,0,0)"><BR></B><I><SPAN
style="COLOR: rgb(102,102,102)">certified professional building designer,
AIBD<BR>certified passive house consultant, PHIUS</SPAN></I>
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