Cob: Insulation

[Kelly, Sean]

Does this same type of thing happen to lumber (vigas, or whatever they are
called) embedded through a cob wall for rafter type things to support a roof
(or a second floor)?  It would seem that would be the case.  Is this not
such a large issue since these are fewer than the pieces in a cordwood wall?
Not that I care if my house leaks a bit... it is good for you, lets out the
nasty air and lets in the clean air...

-----Original Message-----
From: Patricia L. MacKenzie [mailto:ruanmackenzie at hotmail.com]
Sent: Wednesday, September 06, 2000 1:00 PM
To: mudhome at lycos.com; coblist at deatech.com
Cc: duckchow at greenbuilder.com
Subject: Re: Cob: Insulation


Here goes - my question relates to sealing of unwanted openings. I'm given 
to understand the incompatibility between the old and new cob or between 
cement and stackwood, shrinkage is mentioned. If the new is incompatible, 
what is the suggested material for cracks, repair or fill in?
I have to assume we are not going to some company like DuPont for an 
elastomeric material however, I personally think cob, mud and or cement is 
incompatible because of age and therefore some type of new surface to adhere

to is required - like uhm, nails driven into a wooden frame and then gooped 
on? Any thoughts? I'm sure the log cabin people don't use anything organic.
P.
ruanmackenzie at hotmail.com


>From: <mudhome at lycos.com>
>Reply-To: <mudhome at lycos.com>
>To: coblist at deatech.com
>CC: "Mark Piepkorn" <duckchow at greenbuilder.com>
>Subject: Re: Cob: Insulation
>Date: Tue, 05 Sep 2000 17:07:04 -0400
>
>This message is really just from Mark (as opposed to the last one, for 
>which we are equally to blame.   :-)
>
>On Thu, 24 Aug 2000 10:03:23 Russel Johnsen wrote:
>  >Another avenue we are considering is a stack wall cob
>  >hybrid.  The more insulative stack wall would be the
>  >outside with a cob thermal mass interior.  Both walls
>  >breathe so they should be compatable.
>
>This is something I've considered as well. The thing I haven't liked about 
>cordwood, even out at Rob Roy's, is the shrinkage of the wood from the 
>cement matrix (which would also happen if cob was substituted for the 
>cement). Truly, when this happens a building very literally breathes. These

>air leaks can be an enormous source of thermal loss. With a direct-applied 
>plaster (preferably on both sides, and as thick as a person wants - as in 
>cob), these air leaks would be eliminated. Where there's plenty of 
>deadfall, appropriate thinning/harvesting, or after-slash cleanup (sigh), I

>like cordwood. Except for the cement use.
>
>  Last time I talked to Rob Roy (sheesh, it's been, like, two years now), 
>he'd got wind of a cordwood house in Wales where they used cob instead of 
>cement mortar. He didn't know any details, and I haven't heard anything 
>since.
>
>FWIW, building scientist John Straube of the University of Waterloo 
>(Canada) alluded a while back that a small uninsulated mass-walled house 
>could potentially "work" in severely cold climates, and have similar 
>heating-energy requirements to a well-insulated structure with comparable 
>interior space. He supposed the walls would need to be on the order of 
>3'-4' thick, and a frequent or constant heat source would be required 
>inside the structure. Who wants to research this and report back to the 
>list?   :-)
>
>Mark Piepkorn
>duckchow at greenbuilder.com
>
>
>Get your FREE Email and Voicemail at Lycos Communications at
>http://comm.lycos.com
>
>
>

_________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at 
http://profiles.msn.com.