Cob: Fw: rvalue,stabilization

Mon Mar 19 01:33:58 CST 2001

From: john freeman 
To: coblist 
Sent: Wednesday, March 14, 2001 9:05 PM
Subject: rvalue,stabilization

hey there. Bill was wondering about using gypsum board to stabilize his cob wall mixes. 
(snip) "Has anyone added recycled gypsum board (Pulverized) to
their cob mix to stabilize it?   My biggest concern is the low r-value of cob.  Our (loadbearing) walls will be starting at 36 inches thick at
the base, tapering to about 26 inches at the rafters."(snip)

WHY Bill?  Is if for the building department?   You don't need it man.  It may just make matters more complex. It won't add significanly to your R value.

Speaking of which, check out discussions in the archives about cob R values versus thermal storage capacity.  Performance depends greatly on builing shape, size, location, wall thickness and orientation/exposure.  There is no tight formula.
The archives will prove fruitful I'm sure.  Think about adding lots of good short straw too.  Try a sample with as much staw as the cob can hold.  Evidence I've seen would indicate that it is not only more insulative but also reaches a maximun strength.  Worth a test block no doubt.  Cobb in you cold climate may take a few test blocks to get the right mix.  Good Luck
ERTH 
design consultants
250. 882. 4404

Natural builder's Colloquium Spring 2001
check http://www. island.net/~elkec/calendar.htm#colloquium 
-------------- next part --------------
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=iso-8859-1" http-equiv=Content-Type>
<META content="MSHTML 5.00.2614.3500" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV style="FONT: 10pt arial">
<DIV style="BACKGROUND: #e4e4e4; font-color: black"><B>From:</B> <A 
href="mailto:erthdesign at hotmail.com" title=erthdesign at hotmail.com>john 
freeman</A> </DIV>
<DIV><B>To:</B> <A href="mailto:majordomo at deatech.com" 
title=majordomo at deatech.com>coblist</A> </DIV>
<DIV><B>Sent:</B> Wednesday, March 14, 2001 9:05 PM</DIV>
<DIV><B>Subject:</B> rvalue,stabilization</DIV></DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>hey there. Bill was wondering about using gypsum 
board to stabilize his cob wall mixes. </FONT></DIV>
<DIV><FONT face=Arial size=2>(snip) "Has anyone added recycled gypsum board 
(Pulverized) to<BR>their cob mix to stabilize it?   My biggest concern 
is the low r-value of cob.  Our (loadbearing) walls will be starting at 36 
inches thick at<BR>the base, tapering to about 26 inches at the 
rafters."(snip)<BR><BR>WHY Bill?  Is if for the building 
department?   You don't need it man.  It may just make 
matters more complex. It won't add significanly to your R value.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Speaking of which, check out discussions in the 
archives about cob R values versus thermal storage capacity.  Performance 
depends greatly on builing shape, size, location, wall thickness and 
orientation/exposure.  There is no tight formula.</FONT></DIV>
<DIV><FONT face=Arial size=2>The archives will prove fruitful I'm sure.  
Think about adding lots of good short straw too.  Try a sample with as much 
staw as the cob can hold.  Evidence I've seen would indicate that it is not 
only more insulative but also reaches a maximun strength.  Worth a test 
block no doubt.  Cobb in you cold climate may take a few test blocks to get 
the right mix.  Good Luck</FONT></DIV>
<DIV><FONT face=Arial size=2>ERTH <BR>design consultants<BR>250. 882. 
4404</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Natural builder's Colloquium Spring 2001<BR>check 
<A href="http://www">http://www</A>. island.net/~elkec/calendar.htm#colloquium 
</FONT></DIV></BODY></HTML>