exterior wall protection

[patrick newberry]

At 02:51 PM 10/17/96 +0100, you wrote:
>
>
>17 October,  96
>I've seen some discussion about bentonite lately, but am not sure of the
>gist behind why someone would want to use it for plaster.  There was a
>study in the 30's, conducted at some ag. school in South Carolina, that
>investigated materials for protecting the exterior of a rammed earth
>building.  It was found that a portland cement mortar was the best with a
>lime-based mortar not far behind. .


yea Chris.
Ok this is the deal. 
My brother in law puts Portland cement on his "mud" building in west africa
(even roofs)
Now I have heard from the grapevine that cement over adobe will cause the
adobe to 
disintergrate (I not sure what that means except maybe get crumbly?) 
anyway I have some earth Plaster wall over straw and I am in to process of
adding 4ft eaves to protect them from rain. I, at one point thought of
coating the walls in Portland Cement mixture. I am happy with my overhangs
for storing stuff (it's a storage building/workshop) but I am wondering if I
had just coated the stucture would it have been ok. 
I am wondering why the ag school in South Carolina find it ok 
and my brother in law find it ok 
but... some folks out west find trouble with some adobe buildings with
cement coatings???
Pat. (in Georgia)