Cob:

[Shannon C. Dealy]

On Fri, 21 Feb 2003, Jill hotmail wrote:

> Okay, I am still trying to figure this stuff out. The cob walls dry
> hard like rock, right? So how you do put up nails to hang stuff? Do you
> have to pre-plan and insert some wood?
[snip]

It depends on what you are trying to hang (in particular how heavy) and
the characteristics of your cob mixture.  The best approach is of course
to plan ahead and put some wood in the wall to attach to, particularly if
it is a heavy item.  In many cases, particularly for lighter stuff, you
can simply drive a nail or long wood screw or some type of self tapping
screw (I like three inch deck screws), though how well it holds and how
much weight it can handle depends on your particular cob mix.  The best
thing I have found so far for handling heavy objects where no attachment
point was provided in the wall (unfortunately I don't remember what it was
called) is kind of a bolt inside a metal sleeve.  The "bolt" section
doesn't have a conventional head and is tapered, and the sleeve is split
into quarters at the same end as the tapered bolt head.  You drill a hole
in the wall, insert the bolt/sleeve head first into the wall, then tighten
the nut on the end protruding from the wall, this pulls the head into the
sleeve forcing the sides out and locking it into the wall.  I don't know
how well this will hold up over the long haul, but I used a couple of
heavy duty six inch versions of these to attach a quick and dirty plywood
door directly to cob.  I think these are intended as concrete anchors and
are carried by most hardware stores.  There are probably many other ways
you could attach, such as punching a bolt hole through the wall, dig a
larger hole into the wall on the other side, stick a chunk of wood or
metal plate into the larger hole on the other side, run a bolt through the
plate/wood and out the other side of the wall, then use cob to fill in
over the bolt and plate/wood, leaving you with a nice well anchored bolt
sticking out of your wall.

FWIW.


Shannon C. Dealy      |               DeaTech Research Inc.
dealy at deatech.com     |          - Custom Software Development -
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