one more "other thought"

[Becky Myton]

Sorry, I forgot to add this in my last post.

Yesterday I was rereading the ingredients on my usual brand of kitty 
litter, "Natural Choice" (prior to dumping in the box, wise-guys, I *do* 
have better reading material at home!:) ). This stuff is made with 
bentonite clay instead of concrete (which a cat-fancier publication told me 
was in most clumping litters). There's usually a strawbale debate about 
using concrete in plaster coats, with most opinion holding against because 
of its unbreathing nature.

In know bentonite clay can be used as a waterproof underlayment to living 
roofs, but what would it do powdered in the finish coat of plaster? Would 
there be any advantages, or would this just have all the problems of 
concrete in another medium?

Becky Myton