Cob: Horse Manure

[Darel Henman]

Matthew,
  Ocean's letter mentioned that a relief at her place used horse manure
in the mix.  This reminded me of a conversation I had with a fellow in
our local English pub last week.

  The fellow I had talked to, had been involved with restoring historic
buildings back in England and though his particular specialty was in the
oak timber framing, he mentioned that where his from they would use
horse manure in their cob.   

  Is this a local custom?  Does this add the cob (daud)'s durability
and/or water strength?

  Have you run across this in your studies and do you have any mixing
ratios of mixes used that you could share with us?

Darel

Ocean wrote:
> 
> Darel,
> 
> Thanks for the details I left out regarding thermal mass...
> 
> The bas relief cougar was done (on http://www.intabas.com) with a
> simple plaster of red clay (seived), mason's sand (finely seived
> concrete sand), horse manure, and I think Kiko added a little wallpaper
> paste.
> 
> I'll post more of Kiko's amazing art as I get time to.  We're racing
> towards our opening date, with so many details the mind whirls!
> 
> Ocean
> 
> --- Darel Henman <henman at it.to-be.co.jp> wrote:
> > Ocean,
> >   what you wrote can be mistaken and much was probably unintentionaly
> > left out.  Let look at what you wrote.
> >
> > Ocean wrote:
> > >
> > > Cob houses are comfy, if occupied and heated daily throughout the
> > > winter.
> >
> > 2 x 4 house "if occupied and heated daily" are also comfy.  In fact
> > they
> > heat faster with no mass to drag them down.
> >
> >
> > > Every day a cob house is heated the cob absorbs some heat,
> > > bringing the "average" heat  of the "thermal mass" closer to the
> > > desired temperature (70 degrees? seems a little warm for me!).
> >
> > Every day the cob is also loosing heat to the outside, where its
> > presumable colder.
> > Once, charged up to one's desired temperature it will help to reduce
> > quice fluctuations in temperature.
> > Cob houses function best in locations that have large day / night,
> > i.e.,
> > diurnal temperature differences.
> >
> > For cob to work well and not be a drain on energy, it's design must
> > include passive or active solar energy use.  Once a large thermal
> > mass
> > is cold, it takes a lot of btu's to get it up to a comfortable level.
> >
> > Using solar energy is a must to make a cob house as effective as
> > possible.
> >
> > > Even if the walls (aka "thermal mass") of the cob only get 50-60
> > > degrees, the space in the cob is much easier to heat with a Rumford
> > > hearth or rocket stove than say, a yurt tent pitched in a 20 degree
> > > winter climate.
> >
> > Air does heat fast, then when a temperature gradient in the air and
> > walls is produced, the walls would start sinking the heat from the
> > air,
> > and receiving any radiated heat from the burner.
> >
> > Your greatest lost of heat would probably be through your roof.
> >
> > > Now, your argument must leaning towards building with strawbales,
> > since
> > > they have an insulative quality of R50 or so.  But if you want
> > > insulation, please try subscribing to the strawbale listserv.  We
> > here
> > > on the coblist LOVE COB!
> > >
> > Cob buidings would perform much better if insulation was added to the
> > outside, say the north side for example, or if no solar energy could
> > be
> > received.  Many design considerations depend on the location and it's
> > peculiarities.
> >
> >
> > >
> > > Cob houses are cozy and comfy, even in the winter.  This may be due
> > to
> > > the "thermal mass" of cob houses, which is why they tend to be
> > likened
> > > to caves--easy to heat in the winter, cool in the summer.  There
> > was a
> > > reason our distant ancestors like cave-dwelling!
> >
> > Caves has near infinite thermal mass and are, well, below ground".
> > Its
> > hard to compare them to cob buildings which have walls exposed to
> > cold
> > winds directly and don't have extensive berming.
> >
> > True the mass is good, but, it can ALSO have negative effects, if
> > planned wrong.  It's important that people are informed about this
> > and
> > design a cob house to be as effective as possible in my opinion.
> >
> > > Whatever the case, please spend some time in a cob house,
> > especially
> > > during the winter, before theorizing about whether they need
> > > "insulation" or whether "thermal mass" is indeed enough to make the
> > > space cozy.
> > >
> > > As for me, "I love my cob!"  Hey, that might be a cool bumper
> > sticker.
> > > Any takers?
> > >
> > > Ocean
> > >
> > > ps:  Look at the super cool bas relief cougar Kiko sculpted above
> > our
> > > restaurant's front door!  CLICK HERE:  http://www.intabas.com
> > >
> >
> > Its a beautiful relief.  The earth walls are very nice to.  What
> > process, material, and blend did you use on the earth walls?
> >
> > Darel
> 
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