[GSBN] Lime plaster and expansion joints

[Athena & Bill Steen]

On Feb 10, 2009, at 10:32 AM, Laura Bartels wrote:

> Bill,
>
> Thanks for your thoughts.

>
> A year or so ago I went back to look closely at cracks that had  
> developed in various places on the walls of the Waldorf School  
> buildings. Some areas on two of the buildings were through all three  
> coats of cement stucco. As I was doing a bit of moisture  
> investigating as well (including drilling in places that there was  
> no cracking but in areas that were going to be re-touched anyway, I  
> was probing all the areas I could. What was significant was that  
> there seemed to be a correlation between where the probe had little  
> resistance and where the largest cracks were. It appeared that in  
> areas where the straw was not firm and voids not well stuffed or  
> filled, that it allowed more cracking. Now, what the exact  
> explanation is I'm not sure- temperature variations causing  
> cracking, thicker stucco in those spots as you say above, etc. But  
> what seemed clear was that correlation.

Laura,
I think it's a combination of the thicker application and the loose  
straw that has been traditionally used to stuff those cavities.  We  
had to abandon the loose straw technique years ago because the earth  
plasters would never adhere to it.
>
>
>
> These conversations are making me wonder how we collect more of  
> people's experiences relating to things like this, compare them,  
> examine them, and learn more from all that we collectively are  
> doing. Some of you write books, some are very active on this and  
> other lists, some do master's theses, some keep very detailed  
> observations... occasionally we wrangle up some money to do formal  
> testing. It's all critical work. Am I off my rocker to think that  
> there may be some way to throw our lessons learned into a database  
> with sections on various topics, describe as many of the variables  
> as we can, and over time watch for congruences and incongruences?  
> Could it be this same group done privately, to give us a chance to  
> chew on all sorts of things? Maybe its just perhaps another use of  
> this exact same format. Maybe we raise topics periodically- lime  
> plaster, earth plaster, plaster prep, structural systems, etc.
>
Love the idea, you already have most of my two cents on the topic.
As to how, hey, whatever suits everyone else.

B...
Athena & Bill Steen
The Canelo Project
HC1 Box 324
Canelo/Elgin, AZ 85611
absteen at dakotacom.net
www.caneloproject.com