[Strawbale] plaster mixes: what is your favourite recipe?

[Matthew Chase]

Hi all

I'm wondering if anyone who has ever applied plaster of any kind to a 
straw bale wall would be willing to share their favourite recipes with 
me.  I am currently working on a research project to test the moisture 
related properties of various plasters (predominantly earthen plasters 
but lime and cement-lime plasters too) for application to straw bale 
structures, including their behaviour in a simulated wind-driven rain 
scenario.  

Of specific interest are the various and many additives which people 
add to plasters based on claims of improved performance in workability, 
durability, and moisture protection.  These claims should be validated 
both in a laboratory setting, as well as by the experience of 
plasterers throughout the ages.  It is sometimes the case, 
unfortunately, that these claims prove false (see two reports by John 
Straube entitled "Moisture Properties of Plaster and Stucco for 
Strawbale Buildings, available from EBNet and CMHC and compare 
cement-based plaster water absorption with claims that these plasters 
wick water) and testing helps both to discern truth and foster 
acceptance within the building community.

So, please send along any tips, mixes, preferred additives, or thoughts 
that might be of interest to this work.  Part of the purpose of this 
email is also to gauge, by the response volume, the most popular 
plasters in order to adequately focus the work, so please don't be shy!

Thanks,

--------------------------------------
Matthew Chase
Msc. Candidate, Biosystems Engineering
University of Manitoba