[Cob] Late season cobbing (The experimental greenhouse)

[Shannon Dealy]

On Tue, 2 Nov 2010, Henry Raduazo wrote:

> 	I was wondering if anyone has ever tried cobbing into the early 
> winter. I am south of Washington, DC. So far I have had no killing frost, but 
> it could come any day now. I would like to do a couple days more work on my 
> experimental greenhouse, The north and west walls are being made from 
[snip]

As I am likely the only person on this list dumb enough to have barefoot 
mixed cob right through winter (more than once :-) including building at 
temperatures right down to 32 degrees F (ice crystals were coming out of 
the hose), here is what I have learned:

   - Air flow is everything for drying at low temperatures

   - You only need the wall to lose a few percent of it's moisture content
     before it freezes.  This leaves little air pockets for the ice to
     expand into without damaging the cob on the wall.

   - A simple opaque tarp above the building site can keep the cob and site
     several degrees warmer than the surrounding area (preventing freezing
     at night).   The reason is that it significantly slows heat radiation
     from the site into the night sky.

   - String reinforced plastic (which is not opaque) makes a good cover for
     capturing heat from the winter sun and providing light while working
     on a building site.

   - Sometimes a high powered propane heater is your best option.

   - Build your walls which have the least exposure to winter sun and wind
     first as they will need more drying time

I wrote a bit more about this here:

    http://www.deatech.com/pipermail/coblist/2004/007501.html

NOTE: For some reason, google is no longer indexing the full coblist 
archives so searches are not finding everything they used to, however, 
everything is still there.  I am investigating this problem.

FWIW.

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