[Strawbale] Stucco overhead?

[Rob Tom]

On Wed, 08 Nov 2006 18:47:50 -0500, Speireag Alden  
<Joshua.M.Alden.91 at Alum.Dartmouth.ORG> wrote:

> I have some surface-bond cement, and tried to use
> that, but it doesn't like to adhere to the mesh, and comes away in
> wet, cohesive sheets.

Spglbfzx;

Plaster doesn't really adhere to expanded metal lath so much as keying to  
it.

By "keying" I mean that the plaster needs to be pressed through the  
perforations whereupon it will swell slightly larger than the perforations  
on the backside of the lath so that when the plaster hardens, it is  
mechanically locked to the lath.

I suspect that the fibres in the plaster are making it difficult for you  
to press the mud through the perforations thereby preventing plaster from  
grabbing.

Another thing is that expanded metal lath has a "grain" where if you apply  
the plaster with the grain, it tends to to not key properly. I've seen  
people install the lath on walls with the grain running the wrong way so  
that any plaster they applied kept sliding off and landing on the ground.  
The edges perforations need to be angled upwards when the lath is applied  
to walls and you need to apply the plaster against the grain when working  
on overhead surfaces.

Plastering overhead isn't the easiest thing to do in the best of  
circumstances.

Since you are dealing with a rapidly-closing weather window, I wonder if  
it might be possible for you to form and pre-cast the panels indoors and  
then after they've cured, simply cart them out, jack them into place and  
attach them with the appropriate screws in the same manner as fibreglass  
mesh-faced cement mortar boards (aka cement backer board) ?


===* ===
Rob Tom
Kanata, Ontario, Canada
<archilogic at chaffyahoo dot ca>
winnow the chaff from my edress in your reply