--- In papercreters@yahoogroups.com, "Robert & Connie" <losee04@...>
wrote:
>
> Thanks, Forrest
>
> This is a little like the "burlap-crete" dialog we had here a while
> back. If you haven't seen that one, you might like searching that here
> and seeing the fascinating pictures someone baited our interest with
> and then left us hanging with no more input as to how his project
> progressed.
>
> I would think the advantage of the fiberglass cloth is maybe it would
> be less likely to sag during the drying time?
>
> However he was using the burlapcrete for walls of a yute shaped
> building rather than the roof. This sounds very promising for our
> tractor shed, a prelude and experiment on the way to building our dome
> home. I'm thinking this would be a great seal and strengthener for the
> dome cardboard structure in the old Mother Earth article I just
> mentioned here.
>
> Connie
Hi Connie:
This idea has been apparently tested and is promoted by professional
engineers so I think it is legit. Burlap seems too soft to pull
tight enough . The little bit of engineering my father taught me was
that concrete's best quality was compressive strength and worst
tensile so the ability to pull the fiberglass mess taunt would have
to be superior to burlap ,I think. The ability to weave many thin
layers is almost always going to be stronger than one thick one.
Another advantage would seem to be it allows for a thinner mix and
therefore a lighter coating. Burlap is like a sponge and rather weak
so I can see it sagging under the weight. The polyester "burlap" would
probably be better but I would imagine that the reason the experiment
failed was getting in a hurry and using too heavy a mix. If the burlap
was given a thin first coat and built up slowly with the cement it
might have stiffened the burlap and diminished the sagging but it was
probably a misapplication from the start.
The tensioning is everything so I can't imagine burlap would be the
way to go. It was used on rebar framing to hold the concrete in place
temporarily in the ferro cement process but not as the tensile
strength itself. The rebar was the re for tensile strength, this is a
completely different application.
I am assuming a lot but I would say this fellow got excited and used
the burlap for something it was never designed to do.
I have not really studied this idea of ferro-cement but I find it
facinating. I found some information on the burlap but so far none of
it mentioned the latex paint or the wood glue which the engineers
found important. A long time ago I sold a roof coating called Snow
Topping for a friend . It used a cement / latex / Portland mix to
cover hot tar roofs in Houston. I wish I had the mortar mixer he had.
It was like a Kitchen Aid on steroids. The stuff was beautiful and
easy to sell. I would tell the neighbor to come look at the "new roof"
and walk on it barefooted on a typical 100 degree Houston afternoon.
Without the latex it wold have disintegrated in a week. It was not
water proof and had to be re coated every few years but you can't
compare poring the slurry on a flat, dirty hot tar roof and a clean
mess substrate.
This is an interesting subject.
here is a different solution.
http://annesley.wordpress.com/2008/10/06/see-the-pages-for-specifics/
>
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