Cob: RE: RE: Insulation for cob

[The Van Wey Family]

Michael,

I terribly afraid I need to disagree with you an a point. The "just chucking
in" of things... When I suggested the use of the styrofoam beads or other
matter to be imbedded in the cob walls to help with insulative values of the
walls, it was not "alchemy" by any means. As you undoubtedly know, styrofoam is
basically suspended air if you will. As such, it might provide the "bubbles"
you spoke of, which was my point from the beginning of the thread. I do not
know much about cob construction, and even if I had merely just been "chucking"
things in there to try, wo be unto him that prevents the wonderous mind to dare
to create and explore the possiblities of trying new and untried things. If
more had that attitude, we would probably still be in the dark, because surely
edison would not have figured that tungsten was the key to the lightbulb.
Instead it took him over 900 attempts with different matter (including
horsehair!) to finally figure it out.

Sorry - ---> Rant is now complete! Please take no offense!

Shane Van Wey

Michael Saunby wrote:

> On 08 July 1999 16:04, Kelly, Sean [SMTP:SKelly at PinpointTech.com] wrote:
>
> > post, cob is just clay, sand, straw and water.  The strength comes once
> > it is dry.  The clay acts as the mortar or glue, the sand (needs to be
> > angular, not rounded beach sand) acts kinda like interlocking bricks,
>
> I know the new cob builders use rather different mixes but traditional cob
> (once it's gone off) is earth, straw, and some moisture.  The earth is of
> course a mixture of stones (about 1 inch or less) down to sand (though not
> much where I am) and clay.  It's also go a lot of fine gaps in it, since if
> you add water the mass increases considerably but not the volume (a simple
> test of such things). The straw acts not just to hold it together but also
> to hold it apart, reducing the external shrinkage.  Adding lime also
> reduces shrinkage and probably has a reasonable history so your wall might
> even last (if that matters).
>
> In the end it's like the stuff about newspapers earlier this week, most
> solids are poor insulators, it is usually the air trapped inside or between
> layers of the material that keeps heat in or out. Rather than adding funny
> stuff all that's really needed if you want good insulation is lots of fine
> bubbles, which would also reduce the volume of materials needed.  How you
> do that I don't know.  Even so, it's always much better to start with basic
> physics, chemistry and engineering than alchemy.  Just chucking something
> in because it has a certain property is a waste of money, you usually find
> that it's the method of use that gives it the property not some magic
> contained in the material, even newspapers or earth :-(
>
> Michael Saunby
>