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Re: GSBN:Low Tech SB wall
I suggest you contact Mike Pain and or John Zhang
j.zhang@...regarding their expriences with SB wall compression
testing as they did in NSW Australia. They expressly did not support the
stucco and allowed it to slide past the support and pressure beams the
reasoning being that otherwise you are effectively testing the mechanical
stability and capability of the stucco and not the bales. This is due to the
much higher E-modulus of the stucco. Ie the stucco will have to fail first
before the bales start taking any appreciable loading.
In most practical applications the stucco will be taking the load due to the
detailing especially at the foot. Therfore the test as executed down under
could be seen as a worst case scenario. I personally would like to see the
effect of different top and bottom plate stucco bonding details. Besides the
numbers I would also like to see the failure modes. Ie when the bales start
to take the load. I would suggest that the detail as used in the testing
should be a as simple as possible therefore I suggest you don't use any mesh
for the earthplasterd samples as the general practice is not to use mesh. Is
an experienced earth stucco practitioner involved in creating the samples?
If not I would at least consult one with the same amount of experience like
Barbara Jones, John Glassford or Bill Steen regarding recipes and
application details (and not to forget drying times).
With kind regards,
----- Original Message -----
From: "tim Owen-Kennedy" timok@...
> We are winding down the testing portion of the EBNet's straw bale
> construction testing program and we will be building the cyclical in-plane
> test walls in Illinois over the next three weeks. Without going in to the
> details, we are testing 3 earth plastered walls and 3 cement/lime stuccoed
> walls (quickrete exterior stucco). Each of these sets range from
> simplest/most common to reasonably engineered to over engineered. ;-)
> The question that I would like input on is the top plate and base
> for the simplest earth plastered wall. In California we don't have much
> occasion to build with this commonly built wall. We really want to avoid
> folly of a silly solution that everyone will have to replicate. We will
> strap the wall with poly every two feet. This however does not seem to be
> So here is what we're considering:
> Mesh wraped under the sill and over the box beam that just covers the
> and top course of bales. ( most logical for us mesh happy balers though if
> you're gonna mesh top and bottom you might as well go all the way.
> unfortunately that is our mis range wall.
> 16d galvinized nails 4" on center imbedded only one inch into the plates
> box beam.
> Developing a decent way to hold onto the top and bottom plates with
> bamboo pins
> Imbalers, wood 2x2 top and rebar bottom (I really like to avoid this but
> has been done quite a bit)
> 16-18" Sip screws with wide washers installed after the first course and
> an angle up into the box beam (something I've tried with window bucks)
> Also, if someone will be near the Urbana, Illinois testing site and could
> help plaster let me know.