Cob: Re: Earth Floor!

[Patricia Kerns]

Ian

Road Base is basically sand (and rocks, which I screen out) with just enough
clay to make it stick together.  Its a product designed to get superior
compaction with no shrinkage when used as fill under road construction.  I
got the idea for using it from an Austin contractor who'd made several
floors this way.  I actually tried several tests before I started, mixing in
even more sand to one mix and more earth to another.  The mix with more
earth cracked and the one with more sand crumbled and didn't stick together.
I ended up using the mix as is.  The really nice thing about this stuff is
that it seems to be (by design, actually) just the right proportion.  So it
is basically ready-mix.  I went to several demonstrations prior to doing my
own floors where people were starting with earth and clay separately and
mixing it all together.  This was definitely the most labor intensive part
of the whole operation.

Patricia

> Hi Patricia,
>
> Just a short note of caution. It is important to have a much higher
> porportion of sand in your floor mix. Sand is what make floors and cob
> hard. I have heard of some people who have had problems with their floors
> being too soft. I suspect their mix has too much clay. I put just enough
> clay in to stick the sand together, but no more. You would be surprised at
> how little clay you need. My floor is rock hard but I haven't dropped
> anything yet to really test it out.
>
> Ian
>
>