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GSBN:slab edge insulation

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Here is a followup on insulating concrete for slab edge, I
haven't talked to Ken and Polly yet about the foamed concrete
insulation they used.
<font color="#000000"> </font>
<font color="#000000">Physical properties of perlite concrete
vary according to mix designs. Perlite concrete can be made with a
dry density of 20 lb/ft3(320 kg/m3) or with the addition of sand or
other aggregates up to 90 lb/ft3 (1440 kg/m3). The lower the density,
the higher the insulating value.</font>
<font color="#000000"> </font>
<font color="#000000">For most uses to maintain a proper balance
between insulation value and compressive strength, a 1:6 (one part
portland cement by volume to 6 parts perlite by volume) mix is chosen
with a density between 24-30 lb/cf3 (384 and 480 kg/m3).</font>
<font color="#000000"> </font>
<font color="#000000">This provides a k factor range of 0.58 to
0.66 Btu-inch/h-ft2-F (0.085 to 0.095 W/m-k) (<b>R-value = 1.7
inch,  3 inches = 5.1</b>) and a compressive strength of 125 to
200 psi (986 to 1378 Pa).</font>
<font color="#000000"> </font>
<font color="#000000">At the garden center yesterday perlite was
$16 for 4 cu ft.</font>
<font color="#000000"> </font>
<font color="#000000">I used some perlite mix stucco at CMM
sbale building and it was a dream. Lightweight and easy to lift even
at the end of the day.</font>
<font color="#000000"> </font>
<font color="#000000">Probably not good on the net energy front
compared to pumice crete - but more readily available.</font>
<font color="#000000"> </font>

<font color="#000000">--  
David Bainbridge 
Environmental Studies Coordinator 
Alliant International University 
10455 Pomerado Road 
San Diego, CA 92131 
Fax (858) 635-4730 
Ph (858) 635-4616 
<font color="#000000"> </font>
<font color="#000000">The future isn't something hidden in a
corner. The future is something we build in the present. Paulo
Freire</font><font face="Times New Roman" size="+3"