[GSBN] Drainage within a plaster system

[Frank Tettemer]

I really like what you're doing with this, John!

The stitching of 14g wires answers all my concerns of the outer layer of 
render flaking off, or pulling away from the structure.
And I imagine that this stitching would also reinforce the lateral 
resistance of the plaster, when it's ask to act as a wind bracing,
and when it's contributing to seismic resilience.

Would any Engineers on the list want to confirm this? John and I are 
just builders, after all, and speaking for myself, I'm only qualified 
for driving nails, not engineering.
(other than "intuitive engineering".
I _may_ be qualified for that.).

Frank
........................................................................................................................
John Rain Skeemer Swearington wrote:

We/ve used a similar product, with good success, by Benjamin Opdyke: 
http://www.benjaminobdyke.com/visitor/subcategory/subc/rainscreenProducts.

We applied it more or less as Frank says:  we used a thick scratch 
(base) coat of plaster over the bales, and then tied the rainscreen 
(Homeslicker plus Typar) and light stucco lath onto the building with 
14g wires through the bales. The Typar stops the next plaster coat from 
filling the gap.  This sounds more laborious than it was; it went pretty 
quickly. Then we applied  a regular three-coat plaster, though a thick 
two-coat would also work.  We used a custom flashing at the bottom of 
the bottom of the wall to carry away the water.I see

This was in a highly exposed round tower sticking up through a tile 
roof, a fairly challenging location that receives high winds and driving 
rain.  We've gone through the first winter, including some hurricane 
force winds, with no sign of leakage :)

John "Rain Skeemer" Swearingen


On Mon, Jul 8, 2013 at 2:04 PM, Frank Tettemer <frank at livingsol.com 
<mailto:frank at livingsol.com>> wrote:
Hi Sven,

While this flexible drainage plain may well provide the needed path for 
intrusive water, and allow drainage from within the wall plaster,
would it not also prevent bonding of the render to the straw bales in 
the wall assembly?

I'm imagining a 'brown' coat of plaster, worked into the exterior of the 
bales, and the application of the Duraflow material to this first 
plaster coat, while it is still wet and workable. Then the second coat 
of plaster covers the Duraflow material, yes?

Would this compromise the structural needs of the outer skin, in it's 
function for structural engineering and seismic resiliency?

Or, to say it all a different way:
Wouldn't the use of the Duraflow weaken the strength of the wall assembly?

-- 
Frank Tettemer
Living Sol ~ Building and Design
www.livingsol.com
613 756 3884