Cob: Re: how cold can you go?

[Darel Henman]

jen walker wrote:
> >Darel wrote: I recommend that you refer to some of the earthship houses that have
> > been built at high altitude areas, in the U.S., these are cold areas.
> 
> I was surprised to see at earthship.org, that a wee hermitage earthship (not
> big enough for us especially since we both work from home) could cost
> $80,000 US. Can this be true? 
It could be.  I was just referring to their performance.  But, as prices
go
what was included in the $80K you mentioned and how many square feet was
it?.   
For example did it have the completely off grid electrical system, black
and greywater systems, complete
water catchment and cisterns, all plumbing, etc.  

If you did all the work yourself, scavenge materials it would be
significantly less, just as
for cob or any other material.

A lot is a time / money tradeoff.  People who build themselves tend take
a lot longer than
hiring professionals from my observation.  If you have the time its a
good way to go and you
learn a lot.   So you would need temporary housing in the meanwhile.

> 
> I just heard about slip-straw, light clay and straw mix for insulation. Is
> this what you are refering to? 
Yes.


> Do you know if that would be suitable? Would it be the outer wall or need to be sandwiched between cob?
I would use it in the attic and for non-bearing internal partitions.
You could sandwich it between cob, but that would make a lot more work I
beleive.
I'd want to put it outside the cob, but it's not waterproof, just as
strawbale's not.
So something would have to be done to protect it.   Since we're talking
about the north side,
I'd use a long overhang and put a lime plaster over it, if its exposed
to the outside weather.

> >
> > Another good idea would be to build into a south facing hill.  This
> > might preclude the use of cob for the inside areas, though.
> 
> Why is that?
Because if you build into the hill your inside walls would be adjacent
to the hill's earth and
moisture could be a problem.  Also very important, is that you have to
consider the strength required to hold all that earth securely in place. 

Darel