[Cob] asking for a few ideas

[Shannon C. Dealy]

On Fri, 5 Mar 2004, Mary Lou McFarland wrote:

[snip]
> What I'm needing advice on is, HOW DO YOU GUYS DO IT!!!
> I'm married to a teacher who doesn't make a fraction of
> what he's worth.  I've had some health problems which has probably numbered
> how long I will be out there working.  Money is tight.  I've been hoarding
> here and there and I think I could probably get a small start but with cob
> being affordable it also seems to have the drawback of needing to have the
> work proceed continuously so it stays wet on wet so the clay continues to
> adhere to itself. Hopefully, I'll be able to give my building project one
> day per week spring, summer  and fall.  Nothing during winter.  I will be
> working alone most of the time.

  1 - Design your building to be expandable, and don't try to build the
      whole thing at once, start by building the smallest usable piece
      possible.  This way you can get something completed/usable, and
      possibly even move in (or at least use it to store a change of
      clothes, tools, etc.).  You will get alot more done once you are
      living on the site.

  2 - Cob does not need continuous work, and while it is much better to
      apply new cob to cob which is still a little soft, it is not an
      absolute requirement.  Each time you stop working, put lots of holes
      in the surface  where new cob will be bonding, so you at least have
      a good mechanical bond if it drys out.

  3 - If there is any chance that the cob might dry out before you get
      back to do the next layer, throw a good (more or less) waterproof
      tarp over it and weight it down with rocks so the wind can't blow it
      off.  This will trap the moisture on the wall and slow drying to a
      crawl.  If this is drying to slow, try using some tarps you have
      used for mixing cob to cover it, the grinding of the sand in the mix
      on the tarp surface will tend to quickly reduce the quality of the
      seal that the trap can provide.  If it still drys to fast, rig a
      secondary tarp over the building area to provide shade (in summer
      you will probably want this anyway).

  4 - If the cob does dry out and you want a better bond, when you have a
      couple days in a row (or close together), I find the following works
      pretty well:  soak the dry cob surface and surrounding area
      repeatedly with a hose (every five minutes or so)  make sure you
      fill all those holes with water that you left in the surface,  if you
      forgot to leave holes, make some before wetting the surface, I find
      that a drill with a 1" - 1-1/4" wood cutting drill bit (the flat
      paddle shaped ones) work quite well (don't plan on using this bit
      for anything else afterwards :-)  In between wetting the wall, make
      yourself a batch of really wet cob (same basic mix as before, just
      use alot more water), enough to cover the dry cob two to three
      inches thick.  The consistency of this mix should be about like
      pudding, and just barely able to support itself to a thickness
      of three to four inches.  Apply this mix to the dried cob two to
      three inches thick (don't forget to put holes in the surface of
      the fresh cob), then throw a tarp over it to trap the moisture
      if you are going to be around for a while, every few hours check
      under the tarp and if the wet cob appears to be setting-up/drying
      at all, hit it with some more water.  Whenever you get the chance
      after this, continue wetting the fresh cob and surrounding area of
      the wall, right up until you decide to start adding new cob over
      this area.

      Basically the point if this approach is that we know dry cob will
      absorb water, all it takes is time and constant contact, as those
      of you who have done cob in a flood plain can attest to :-(
      This new layer of cob is specifically intended to provide a constant
      source of water to the dried surface, as well as new, wet cob for
      the surface to bond to.  By keeping it as wet as possible, the dried
      cob underneath will start to soften slightly and the clay will be
      able to form a better bond than it might otherwise.  I can't say if
      this will be as strong as applying to soft cob (though my guess is
      that it won't be), but it may come close, and is certainly much
      stronger than any other approach I've used.

  5 - With regard to health problems, you don't specify what they are,
      but a great deal can be done to alleviate most back problems (I have
      a very long history of serious back trouble), or compensate for many
      other issues that might get in your way.  If you want to discuss
      this further, email me privately.

  6 - For what it's worth my place was built entirely alone.

> On top of that , my husband has a deep and abiding affection for indoor
> plumbing and in the dead of winter, I must admit that I wholeheartedly
> agree.  So, our reasonably
> sized,earth-friendly house will need all the amenities.  I can do all the
> cold wiring so I'm not so concerned about that  but  plumbing makes me
> nervous because I am totally clueless on the subject.  I'm one of those
[snip]

I kind of felt that way, and while our winters are generally fairly mild,
I got so I didn't even notice the walk to the green house (about 75
feet away) where the plumbing is located, even when I was wearing sandals
on bare feet through a foot of snow in 15 degrees (I did however have a
nice propane heater in the green house I could turn on while I was there).
Of course lots of people have worse winters, so this may be much more
of an issue for you.  In any case, plumbing isn't that difficult, maybe
you can find a friend or family member who can bring you up to speed.
Of course for the toilet, a sawdust toilet doesn't require any plumbing.

FWIW.

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
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