[Cob] Cob vs adobe

[Dean Sherwin]

good question with more answers than can fit in a small email IMO...
depends on climate and soil.   (and why not compare rammed earth or 
pise too, they are perhaps even more adaptable)
After all cob originally is confined to a very specific geographic 
area within  England  - in China and India its more widespread but 
not under that name.
Adobe it turns out is popular in S'west particularly because of long 
dry spells which allows drying out of bricks.   Then they can be 
built with relatively fast.
Also easily modified nowadays with bitumen or even cement - in 
practice this is to make drying and handling more dependable rather 
than for strength and resistance in the wall.
Cob is slower to build with but admittedly goes right up into the 
wall.   Just needs the right mix of mud and plenty of labor. In 
general they laid up 18" height of wall or so and then waited weeks 
before coming back and putting up the next layer, meanwhile working 
on other agricultural tasks.  But you could go from building to 
building if you had a dedicated crew and enough steady work.  Winter 
is a problem some places.
In a developed adobe economy such as New Mexico the adobes are made 
in a yard and purchased as necessary, makes it quicker and much more 
dependable.  But that makes it more expensive for the dedicated self builder.
Adobes are associated with a more refined architecture generally at 
least now.  The Mosque at Abiqiu NM is stunning.  Cob buildings are 
generally but not necessarily more humble and "cottage like"  (but 
that may be for cultural and historical reasons).  Easier to go 
higher with adobe.
Bam in Iran is adobe not cob - probably the most significant 
assemblage of earth architecture anywhere (was)

By the way for more background on adobe - and for info on earth 
floors as discussed here recently, also making domes etc, I looked at 
my CD copy of  the Earthbuilders Encyclopedia by Joseph Tibbets, 
an  adobe guy from NM.  Not sure if Charmaine carried that - 
probably.  I could excerpt pieces on floors or etc for anyone that needed it
Dean Sherwin



>Today's Topics:
>
>    1. A Question for Everyone (M40345)
>    2. Re: A Question for Everyone (Shannon Dealy)
>    3. Re: A Question for Everyone (Patrick Newberry)
>
>
>----------------------------------------------------------------------
>
>Message: 1
>Date: Thu, 29 Jul 2010 15:06:18 -0400
>From: "M40345" <M40345 at tampabay.rr.com>
>Subject: [Cob] A Question for Everyone
>To: <coblist at deatech.com>
>Message-ID: <8ADAC128DC754C97AFED04970B374590 at pc1>
>Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>         reply-type=original
>
>Howdy Yall,
>
>What are the advantages of using cob over adobe or adobe over cob??
>
>Thanks,
>David
>
>
>
>------------------------------
>
>Message: 2
>Date: Thu, 29 Jul 2010 13:43:47 -0700 (PDT)
>From: Shannon Dealy <dealy at deatech.com>
>Subject: Re: [Cob] A Question for Everyone
>To: M40345 <M40345 at tampabay.rr.com>
>Cc: coblist at deatech.com
>Message-ID: <Pine.LNX.4.64.1007291326180.10135 at nashapur.deatech.com>
>Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
>
>On Thu, 29 Jul 2010, M40345 wrote:
>
> > Howdy Yall,
> >
> > What are the advantages of using cob over adobe or adobe over cob??
>
>Cob:
>     Typically greater structural strength (due to much higher straw content)
>     Monolithic (no built-in fracture lines at mortar joints)
>     Easily sculpted to whatever shape you want as you build
>
>Adobe:
>     Pre-dried so:
>        No shrinkage
>        No daily height limits due to required drying time
>        Can be plastered immediately
>     Explicitly listed in some building codes
>     More familiar to building officials
>
>Shannon C. Dealy      |               DeaTech Research Inc.
>dealy at deatech.com     |          - Custom Software Development -
>Phone: (800) 467-5820 |          - Natural Building Instruction -
>     or: (541) 929-4089 |                  www.deatech.com
>
>
>
>------------------------------
>
>Message: 3
>Date: Fri, 30 Jul 2010 10:13:44 -0400
>From: Patrick Newberry <PNewberry at habitat.org>
>Subject: Re: [Cob] A Question for Everyone
>To: "coblist at deatech.com" <coblist at deatech.com>
>Message-ID:
>         <9919C1535257D44BA312E95A0EB99A44DD80045AA1 at ATLEXCH01.HFHI.org>
>Content-Type: text/plain; charset="us-ascii"
>
>With Adobe, you have to make the bricks by using forms and have them 
>lay out in the sun till they dry, then assemble them.
>
>With Cob you can just make a batch as you go, thus for a wetter 
>climate that can be an advantage, on the adobe side, if you have 
>the  bricks make then of course you can go more than 12 inches per 
>day since there would be no sagging in the walls since the bricks 
>are already dry.
>
>Pat
>
>-----Original Message-----
>From: coblist-bounces at deatech.com 
>[mailto:coblist-bounces at deatech.com] On Behalf Of M40345
>Sent: Thursday, July 29, 2010 3:06 PM
>To: coblist at deatech.com
>Subject: [Cob] A Question for Everyone
>
>Howdy Yall,
>
>What are the advantages of using cob over adobe or adobe over cob??
>
>Thanks,
>David
>
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>End of Coblist Digest, Vol 8, Issue 140
>***************************************



Dean Sherwin CPE
Certified Professional Estimator
LEED Accredited Professional
CONSTRUCTION COST MANAGEMENT
3, Cherry Street
PO Box 11
Media, PA 19063-0011
(610)892 8860
fax (610) 892 7862
costman at verizon.net