[Strawbale] Tashcrete again

[Chris Green]

Stone Tool wrote:
> Chris:
>     I hadn't heard of this system...... though it appears that the 
> blocks are 100% polystyrene (recycled) and are used as forms into 
> which concrete and rebar are poured.  I had an interesting read 
> checking this out...........    What I am proposing is an aggregate 
> and monolithic which is a horse of a different color.   Bits and piece 
> of junk..... straw, eps, shredded paper, perhaps old baler twine 
> (which is in abundant supply here along with net wrap wet down with 
> liquid cement enough to create an adhesive bond and hold things 
> together.... simply dumped into forms to create a monolithic wall 
> which then would be covered in stucco after applying a steel lath 
> covering.  It would be light, and have a fairly decent R-value, but 
> not a great deal of strength on it's own... mostly a filler.
I'm pretty confident that what you propose is do-able. I have read about 
people making blocks, for instance, out of sawdust, wood chips, 
shavings, chopped up styrofoam, etc., and so on.  And of course, 
papercrete and its' variants,stuff like 'hempcrete.' (Not an option yet 
below the 49th parallel.. :-) But one of the Dakotas is trying to make 
this fibre legal to grow, or was a few months back. )
Charmaine Taylor's dirtcheapbuilders site might have some articles or 
info on some of these variants.
http://www.dirtcheapbuilder.com/
She also posted a message about "kitchencrete" on the 
Organic_Architecture list a few days back. Kitchencrete includes clay, 
among other things, and some artists are using this material for 
sculpturing art and, ummm, "whimsies," as seen here:
http://www.paverpol.com/photogallery.html
So that is one possible additive.
My nephew argues in favour of "pumicecrete," pumice being a good 
additive to make concrete lighter and to add some insulating value. I 
believe you might be close to a pumice quarry where you are, so that's 
something to consider as well.

A hybrid mix surely must be possible, especially when used as an infill 
panel: then the building material doesn't really have to be able to 
withstand the 300psi minimum that is required for masonry construction 
"to code" for a one story structure.( I should check that figure: it's 
been a while since I read up on it...) At this moment, I think I'd opt 
for using integral rebar. However, only experimenting will tell if it's 
really required for, say, 2' x 4' x 8'-10' tall  infill panels. Hmmm. 2' 
deep? Probably don't need rebar. Stucco lath should do it. The folks in 
Alberta who make the pre-fab SB panels (Gen-X Systems) use stucco mesh, 
I think.

Oh, I see Gen-X's  various websites are unavailable at this time...

Somewhere in my collection I have a copy of Fine Homebuilding which 
shows how one builder in Montana made his own tilt-up concrete panels on 
site: When finished, the exterior of the house looked like it had been 
built out of stone. I'll look around to try to find it and send along 
the issue number, but I don't recall seeing it for some time. Maybe one 
of our list members has a collection of these mags and can find it?
>
>     There have long been similar systems to the Rastra, made of new 
> foam enabling concrete to be poured into foam forms that interlock and 
> remain in place..... an expensive system.
I haven't price compared these beyond finding out the blocks are around 
$7.50CAD each. There are two houses built from ICF blocks within a block 
from me, and a bunch more about 10 miles away in another location. Given 
the choice, I'd go for the forms with the recycled material if I were to 
use this stuff. It use to cost our municipalities $65 a ton to send 
stuff to a landfill, but that was 10-15 years ago. The price has 
probably doubled or tripled since.
Recycling useful trash can save tax dollars. :-)

Cheers,

Chris Green.