[Cob] Thanks for the ideas

[Shannon C. Dealy]

On Mon, 8 Mar 2004, Mary Lou McFarland wrote:

> SHANNON.. thanks for addressing the wet on dry issue, that was
> my biggest concern.  How long, in your experience does it take for the cob
> to dry?

This depends on alot of things (including what one means by "dry").  In
the context of drying to much to readily add fresh cob, I find in this
area (Western Oregon), a tarp over the wet cob will keep it soft enough to
directly add to it for weeks in the middle of summer (in some cases to
soft, so I use a worn mixing tarp which is more breathable to speed it up
a little).  This is something you are going to have to experiment with,
and it will change depending on your most recent weather, but the hotter
it gets and the drier the air is, the faster it will dry.  With no
protection from the sun, in 90+ degrees, and very dry conditions, a one
foot tall section of fresh cob can set fast enough to take a new layer on
top of it in just a few hours, however, allowing cob to dry this fast is
not a good idea as it will tend to cause alot of cracking.

> I was wondering..If I build up the outside of the edges of the wall
> and basically flood my surface befor e tarping would it possibly  be the
> right consistency still when I return a week later?

It may actually be to wet, you will need to experiment, my feeling is that
building up the edges will be extra effort for no reason, I think in most
cases, the tarp will be more than adequate by itself.

>  You said that you built your place completly alone.
>  How big is it?

120 square foot exterior footprint (70 sq ft interior floor + a loft)

> and what shape?

Round

> and how did you manage the roof?
[snip]

The roof structure is built shed style, using 2x6 by 16 foot boards on 16"
centers which I just carried up inside the building, then the outside is
sheathed in 1/2" plywood (not my favorite choice, but the best for the
circumstances), then covered with 30 pound roofing felt and finished with
interlocking enameled steel roofing which came in either 12" or 16" wide
panels (I don't remember which width I used, the one I chose was available
in both).  The most difficult part was getting the 1/2" plywood onto the
roof, basically I slid them up an extension ladder as I climbed up below
it, then when about 1/2 the sheet was protruding above the top of the
ladder, I would give it a hard push and it would topple over onto the
roof, after which I would finish climbing up and move it into place.  This
last push is the most difficult and dangerous part, since it is sticking
up above the roof, if the wind catches it, it may come back down on top of
you (it did one time on me but I was able to grab it and control its fall
without falling off the ladder).  This could be made safer and/or easier
by using a longer ladder so you can run the plywood up at a shallower
angle (less chance of the wind catching it, and easier to push up), or you
could pay to have the plywood delivered to your roof, some places that
sell roofing materials will deliver them right to the roof top.

Note about soldering plumbing mentioned elsewhere in your post, make sure
if you are using strawbales anywhere that you clean up all the loose straw
anywhere near your soldering work, and plaster or at least wet the surface
of any bales that must remain near where you solder.  There have been a
few straw bale building construction disasters relating to sparks/fire
while the building is still being built.

Shannon C. Dealy      |               DeaTech Research Inc.
dealy at deatech.com     |          - Custom Software Development -
                      |    Embedded Systems, Real-time, Device Drivers
Phone: (800) 467-5820 | Networking, Scientific & Engineering Applications
   or: (541) 929-4089 |                  www.deatech.com