[Cob] Cob Bale Construction

[Marilyn Pratt]

Hi, Michael -

What Ianto does is put a thick layer of cob on the interior of the north-facing 
wall, for solar gain through windows in the winter.  Appropriately-sized 
overhang prevents the same in summer so the house doesn't over-heat.  The 
exterior only gets enough cob to seal the straw against the weather.

thanks -
marilyn




________________________________
From: Michael Threewit <mliiiwit at gmail.com>
To: coblist at deatech.com
Sent: Mon, December 6, 2010 7:56:09 PM
Subject: Re: [Cob] Cob Bale Construction

If the climate you're building in is cold or hot enough to warrant
(strawbale) insulation, is there really a lot of gain to use straw bales
only on the north side (or south side in southern hemisphere)?  After all,
in winter, solar gain hours are so few that gain from exterior exposure on
cob has to be negligible and interior gain via windows is the only
substantial benefit.  During the other 16-24 hours of the day, there's
negligible, if any, difference in temperature at the north side of the house
vs. the south side of the house.  Remember, wind chill is only felt by
flesh, so prevailing wind is irrelevant except for drafts.  In the summer,
insulation would only be needed in humid areas where overnight ambient
cooling is negligible. Otherwise, insulation is moot for hot weather.

It seems that if insulation is warranted - cold winters and/or hot & humid
summers - the best solution is all strawbale construction, or structural cob
with strawbale insulation on all sides in addition to high r-value ceiling /
roof insulation, which is most important regarding insulation in cold
climates and hot climates with a hot roof.  Generally, insulation is
essential for heating and cooling efficiency except in lower latitude desert
climates, unless you like a warm & humid and/or cold interior environment,
or low heating and cooling efficiencies .

On Mon, Dec 6, 2010 at 2:00 PM, <coblist-request at deatech.com> wrote:

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>   1. Re: Cob Bale Construction (Henry Raduazo)
>   2. Re: Cob Bale Construction (Reno Derosier) (Mia Hessel)
>   3. Re: Cob-Bale Walls (Benjamin Brownell)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 5 Dec 2010 17:11:56 -0500
> From: Henry Raduazo <raduazo at cox.net>
> Subject: Re: [Cob] Cob Bale Construction
> To: Reno Derosier <reno.derosier at gmail.com>
> Cc: coblist at deatech.com
> Message-ID: <12A09165-1221-4741-ADBF-B8F7F1DDCEE3 at cox.net>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> I helped to build a cob/bale hybrid in Wales I build an hybrid shed
> in Clarindon a few miles north of Washington, DC and Ianto has built
> several cob/bale structures in Coquille, OR. So far as I know none of
> these structures has had any problems.
>        Ianto builds his bale and cob walls at the same time working the cob
> into the face of the bale as he goes. I used my bales as a temporary
> lode bearing wall. The roof was connected to the ground by diagonal
> braces during construction of the cob wall. When the cob wall was
> completed I removed the braces. Cob became the permanent support.
>        I did have one incident of the cob falling away from the bale when I
> built too fast and too wet. Note here, that I am making very wet cob
> with a tiller, and I tried setting more than a foot in a day.  For
> the most part this was a weekend project so there was at least one
> week of drying between batches. I might have had more of a shrinking
> problem if I built faster. I believe the falling away problem could
> be eliminated by providing dead man anchors on the back side of the
> bale to the front side of the cob during construction.
>        If you want pictures I can send them, but not through the Cob List.
> You have to send a separate request. It should be noted too that the
> cob/bale hybrids in Coquille are made from cut bales. You start with
> a two string bale, clamp it in a press made of 2"x4" studs and
> restring it to make it into a 4 string bale. Then you cut the four
> string bale in half to make two thin bales 10-12 inches thick.. If
> you laminate this with a 12 inch thick cob wall you have a wall
> thickness of only two feet and plenty of strength to support any roof
> assuming you have decent quality cob.
>        Cutting the bales is best done with a Wood Miser or other big band
> saw if you have one, but it can also be done with a chain saw. That
> is how Ianto does it.
>
> Ed
>
>
> On Dec 5, 2010, at 10:30 AM, Reno Derosier wrote:
>
> > Hi All;
> >
> > Working with an architect here in Eastern Europe to build a cob
> > bale house
> > to code. My partner just finished a permaculture course in Turkey
> > where she
> > was advised not to do both cob and bale construction.
> >
> > Does anybody have input on the pros and cons of doing such. The
> > permaculturist was concerned about the integrity of the well where
> > the two
> > items met.
> >
> > Thanks
> >
> > Reno
> > _______________________________________________
> > Coblist mailing list
> > Coblist at deatech.com
> > http://www.deatech.com/mailman/listinfo/coblist
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 6 Dec 2010 11:55:26 +0000 (GMT)
> From: Mia Hessel <tinkasbonus at yahoo.dk>
> Subject: Re: [Cob] Cob Bale Construction (Reno Derosier)
> To: coblist at deatech.com
> Message-ID: <320011.35633.qm at web29717.mail.ird.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> My experience with cob and bale is from my only hands-on experience with
> cob. The northern wall was to be built with bales. They were not tied down
> but placed on top of a small cob foundation with support from maybe 10 cm of
> cob on either sides.
> Strawbale sinks when there is load applied from the roof. Cob sinks or
> shrinks less which may cause cracks, and thin cob walls does not bear load
> and may crack or create hollow parts between bale and supporting wall.
> I dont know how others have worked with these issues, but maybe an idea
> would be to structurally seperate the parts with strawbale from the parts
> with cob. Maybe with collums or windowparts. The joins between bale and cob
> could be strengthened by using links like sharp and long imbedded wooden
> pecks. We soaked the bales in clay-splip to create a better join, but I
> don't know how well that worked. Ideas are very welcome.
> ?
> Mia, DK
>
> --- Den s?n 5/12/10 skrev coblist-request at deatech.com <
> coblist-request at deatech.com>:
>
>
> Fra: coblist-request at deatech.com <coblist-request at deatech.com>
> Emne: Coblist Digest, Vol 8, Issue 214
> Til: coblist at deatech.com
> Dato: s?ndag 5. december 2010 21.00
>
>
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>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 5 Dec 2010 17:30:52 +0200
> From: Reno Derosier <reno.derosier at gmail.com>
> Subject: [Cob] Cob Bale Construction
> To: coblist at deatech.com
> Message-ID:
> ??? <AANLkTim7VD2up5ePzYjfjuHE66_wM82fZLT3oUoBzEHC at mail.gmail.com>
> Content-Type: text/plain; charset=UTF-8
>
> Hi All;
>
> Working with an architect here in Eastern Europe to build a cob bale house
> to code. My partner just finished a permaculture course in Turkey where she
> was advised not to do both cob and bale construction.
>
> Does anybody have input on the pros and cons of doing such. The
> permaculturist was concerned about the integrity of the well where the two
> items met.
>
> Thanks
>
> Reno
>
>
> ------------------------------
>
> _______________________________________________
> Coblist mailing list
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>
> End of Coblist Digest, Vol 8, Issue 214
> ***************************************
>
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 6 Dec 2010 10:48:13 -0800 (PST)
> From: Benjamin Brownell <benpbrown at yahoo.com>
> Subject: Re: [Cob] Cob-Bale Walls
> To: coblist at deatech.com
> Message-ID: <237814.32472.qm at web51003.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> Several ways to successfully combine these walls, paying attention to a
> couple of constraints:
> - Put loads down onto walls of the same type, so that there is not uneven
> settling or shifting under stress. You can bring a bale wall to a cob wall
> at a corner, but don't spread a bearing point/beam across them. If bearing
> on the bales, compress them very well ahead of plaster. Also create a good
> tensional connection between both walls to bond them together against
> relative motion, this may take some creativity. Normally corners are keyed
> together out of one material.
> - Consider your designs carefully for how and why to combine them. Several
> homes employ bale exteriors for insulative properties, and cob interior
> walls for thermal mass and dimensional flexibility. Combining both in
> exterior may be at cross purposes
> - You will probably want to vary your foundation system where the wall type
> changes, or make sure you have something that works well for both types.
>
> Message: 1
> Date: Sun, 5 Dec 2010 17:30:52 +0200
> From: Reno Derosier <reno.derosier at gmail.com>
> Subject: [Cob] Cob Bale Construction
>
> Hi All;
>
> Working with an architect here in Eastern Europe to build a cob bale house
> to code. My partner just finished a permaculture course in Turkey where she
> was advised not to do both cob and bale construction.
>
> Does anybody have input on the pros and cons of doing such. The
> permaculturist was concerned about the integrity of the well where the two
> items met.
>
> Thanks
>
> Reno
>
>
>
>
>
> ------------------------------
>
> _______________________________________________
> Coblist mailing list
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>
> End of Coblist Digest, Vol 8, Issue 215
> ***************************************
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