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<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>Hi <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>I am trying to get more info on the use
of Perlite for underfloor insulation. (been to www.perlite.org)<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>I am involved as a consultant to a
project in <st1:City w:st="on"><st1:place w:st="on">Johannesburg</st1:place></st1:City>,
where we are using under floor hot water heating for winter (pipes are being
embedded inside a concrete slab) and so need to insulate under the slab. I have
suggested we look at using a layer of 100mm of Perlite. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>However, the Project manager has just
come back to say we must use the closed cell polystyrene as he is worried about
the Perlite absorbing water and is concerned that as a result it will loose its
insulating properties. We have quite a water logged site with lots of clay and
silt in the soil and the buildings in question are being dug into the back of
the slope.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>Various info says it is “water repellent”
but I notice the details – the 2 that I could find – included some
kind of a capillary break under and over the Perlite or a layer of plastic damp
proofing underneath (as would be under a concrete slab anyway) and a layer of “oil
paper” on top to separate it from the concrete. I also see it is used in
insulating lightweight screeds and concrete work…..where it clearly
retains its insulating properties despite being encapsulated in concrete with
its relatively high moisture content……or does one treat the Perlite
in some way to prevent it absorbing moisture???<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>Can anyone input here ….as while we
can get the Perlite here, the suppliers have no experience with using it in the
building industry……and I am loath to let the project use the closed
cell polystyrene as it is a particularly environmentally damaging material which,
uses benzene and ozone damaging HCFC’s in its manufacture.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'> <o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:green'>Any input would be really valued</span></font><font
size=2 color=green face=Arial><span lang=EN-US style='font-size:10.0pt;
font-family:Arial;color:green'>,<o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:green'>Thanks <o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span lang=EN-US
style='font-size:10.0pt;font-family:Arial;color:green'>Andy Horn<o:p></o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span lang=EN-US
style='font-size:11.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span lang=EN-US
style='font-size:11.0pt;font-family:Arial;color:green'><o:p> </o:p></span></font></p>
<p class=MsoAutoSig><font size=2 color=green face=Arial><span lang=EN-US
style='font-size:11.0pt;font-family:Arial;color:green'><img width=576
height=119 id="_x0000_i1025" src="cid:image001.gif@01CBF2BF.12EDF0D0"></span></font><font
color=green><span lang=EN-US style='color:green'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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