[GSBN] Perlite u/floor insulation

[Andy Horn]

Hi 

I am trying to get more info on the use of Perlite for underfloor
insulation. (been to www.perlite.org)

 

I am involved as a consultant to a project in Johannesburg, 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. 

 

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.

 

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???

 

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.

 

 

Any input would be really valued,

Thanks 

Andy Horn

 

 



 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sustainablesources.com/pipermail/gsbn/attachments/20110404/e8c11936/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image001.gif
Type: image/gif
Size: 15324 bytes
Desc: not available
URL: <http://lists.sustainablesources.com/pipermail/gsbn/attachments/20110404/e8c11936/attachment.gif>