[Cob] RE: Stone in cob

[phil]

We are currently working on a cob-cordwood home here in NC. We have added about 5% lime to the cob for extra strength and short of taking a sledge hammer to the wall (I dare anyone to do that to their home) it has bonded well witht he wood. VERY hard and quick setting as a mortar. We also haven't had a lot of shrinkage. Time will tell as to durabilty.

Phil Hawn, President
The North Carolina Natural Building Coalition
http://naturalbuilder.org
cob, strawbale, cordwood and other sustainable earthbuilding techniques

 --- On Mon 08/16, otherfish < otherfish at comcast.net > wrote:
From: otherfish [mailto: otherfish at comcast.net]
To: bonnie.morse at content-mgmt.com, coblist at deatech.com
Date: Mon, 16 Aug 2004 17:20:41 -0700
Subject: Re: [Cob] RE: Stone in cob

Cob gets it's strength from being built massivly as COB, not something else.<br>Cob bonds well with cob, but poorly with other materials.  Cob as mortar<br>will do little more than simply fill the spaces between whatever you are<br>mortating.  The compressice strength of cob is low comparred to cordwood or<br>stone.  Using cob as a mortar in a stone or cordwood construction will make<br>the mortar the weakest link in the wall system.<br>Not something I'd do.<br>If you want a mortar that doesn't use portland cement, go for lime sand<br>mortar.  It haS a long history of successful use as mortar.<br><br>john fordice<br><br><br>on 8/16/04 3:51 PM, Bonnie Morse at bonnie.morse at content-mgmt.com wrote:<br><br>> My old Materials Science book from college said that gravel with sharp edges<br>> makes stronger concrete than gravel with smooth edges.  I guess the same<br>> would apply to sand particles in mortar or cob.<br>> <br>> Bonnie in OR<br>> <br>> -----Original Message-----<br>> From: coblist-bounces at deatech.com [mailto:coblist-bounces at deatech.com]On<br>> Behalf Of Amanda Peck<br>> <br>> <snipped><br>> <br>> A propos of not a whole lot, I've been reading a mystery story involving an<br>> earthquake.  Author gives lots of information about earthquakes.  Her point<br>> is that the sizes and shapes of particles in mortar are what is important,<br>> not all the same, and for sure not all rounded.  (Sarah Andrews, Fault Line)<br>> <br>> <br>> _______________________________________________<br>> Coblist mailing list<br>> Coblist at deatech.com<br>> http://www.deatech.com/mailman/listinfo/coblist<br><br><br>_______________________________________________<br>Coblist mailing list<br>Coblist at deatech.com<br>http://www.deatech.com/mailman/listinfo/coblist<br>

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