Cob: plastering adobes, clarification
ben graham
benfrankg at hotmail.com
Sat Mar 3 14:37:49 CST 2001
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<P>Thanks for clarifying John. I was refering to "earthen" plasters in my response to the original message. I also believe, like Annike(sp?) that portland stucco did not work with adobe or any earthen structure.</P>
<P>Thanks</P>
<P>BenGraham<BR><BR></P></DIV>
<DIV></DIV>
<DIV></DIV>>From: John Fordice <OTHERFISH at HOME.COM>
<DIV></DIV>>Reply-To: otherfish at home.com
<DIV></DIV>>To: ben graham <BENFRANKG at HOTMAIL.COM>
<DIV></DIV>>CC: adobe50 at hotmail.com, coblist at deatech.com
<DIV></DIV>>Subject: Re: Cob: plastering adobes
<DIV></DIV>>Date: Fri, 02 Mar 2001 17:48:54 -0800
<DIV></DIV>>
<DIV></DIV>>Experience has shown the use of portland cement plaster (commonly known
<DIV></DIV>>as stucco) to be detrimental to earth walls.
<DIV></DIV>>As I understand it, what happens is: The stucco will develop cracks (
<DIV></DIV>>as stucco does ) & this will let water into the wall. Since the stucco
<DIV></DIV>>passes water vapor more slowly that the earth wall, the moisture will
<DIV></DIV>>tend to collect in the outer portion of the earth wall. When the wall
<DIV></DIV>>cools at night or in cold weather, the moisture that has thus been thus
<DIV></DIV>>essentially trapped in the wall will then condense on the backside
<DIV></DIV>>(earth wall contact side) of the stucco and cause a softening of the
<DIV></DIV>>earth wall it that point. This ultimately results in a spalling off of
<DIV></DIV>>the outer layer of the earth wall and a loss of bond between the wall at
<DIV></DIV>>the stucco covering. The stucco then is free to crack even more,
<DIV></DIV>>aggravating the condition & it eventually comes loose and takes a
<DIV></DIV>>portion of the outer surface of the wall with it.
<DIV></DIV>>So the stucco which was put on the wall to protect it, actually damages
<DIV></DIV>>the wall & makes for greater erosion of the wall than if it had been
<DIV></DIV>>left un plastered.
<DIV></DIV>>
<DIV></DIV>>If you wish to plaster cob, use an earth or lime sand plaster.
<DIV></DIV>>
<DIV></DIV>>ben graham wrote:
<DIV></DIV>> >
<DIV></DIV>> > Laura,
<DIV></DIV>> >
<DIV></DIV>> > I think you have the right idea. Plastering adobe is just like
<DIV></DIV>> > plastering cob. All the in between brick spaces actually support the
<DIV></DIV>> > plaster better, so no lath is necessary.
<DIV></DIV>> >
<DIV></DIV>> > Best
<DIV></DIV>> >
<DIV></DIV>> > Ben Graham
<DIV></DIV>> >
<DIV></DIV>> > >From: "Laura Guldin"
<DIV></DIV>> > >Reply-To: "Laura Guldin"
<DIV></DIV>> > >To: coblist at deatech.com
<DIV></DIV>> > >Subject: Cob: plastering adobes
<DIV></DIV>> > >Date: Thu, 01 Mar 2001 22:31:54
<DIV></DIV>> > >
<DIV></DIV>> > >Hello yaall,
<DIV></DIV>> > >I am in Texas visiting my friend who's building an adobe. She's
<DIV></DIV>> > >cement
<DIV></DIV>> > >stuccoing the outside (not my idea) and I am talking to her about
<DIV></DIV>> > >earth
<DIV></DIV>> > >plastering the inside. The adobes are cement stuccoed together.
<DIV></DIV>> > >Anything
<DIV></DIV>> > >special about adobes.? She put lathing on the outside adobes. I
<DIV></DIV>> > >don't want
<DIV></DIV>> > >to do that.
<DIV></DIV>> > >Any ideas or hints? Is it pretty much like plastering cob?
<DIV></DIV>> > >Thank you kindly
<DIV></DIV>> > >Ulani
<DIV></DIV>> > >_________________________________________________________________
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<DIV></DIV>> >
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