[Cob] Alum and Soap over horizontal Lime Plaster surfaces?

[littlehouseantiques at att.net]

-------------- Original message from "Amanda Peck" : -------------- 

> 
> Got links? 
> 

http://www.potkettleblack.com/natbild/canelo_wall6.html

This is the page where Bill Steen (of the Canelo Project) mentions 
about horizontal lime surfaces on roofs in Mexico that use a water 
repellent mixture of alum and soap to prevent absorption of water."

So how 'bout it, anybody have any "hands-on" experience with Alum/Soap?


Kathy