[Cob] Re: Leaking Papercrete Roof

[Raduazo at aol.com]

    I wonder: If you have to apply an Asphalt Emulsion or any other 
waterproofing compound over paper-crete in order to make it waterproof then why use the 
concrete at all? I have been using paper/cob as a plaster substitute for cow 
dung/cob with a heavy finish layer of boiled linseed oil. I have never tried 
this as a roof, but so far paper/cob has held up pretty well as a wall coating 
on a cob playhouse that has no roof. (Pictures available on request)
     I plan on using this or something similar to roof over different cob 
playhouse at St. John's Preschool, and I am still considering the options. I 
understand that water glass has been tried (on walls), but on occasion water gets 
through the coating wetting to the lower layers of the wall and the water 
glass prevents evaporation turning sections of the wall into mush. Not good! 
Asphalt might do the same, but evaporation from the bottom surface of a roof might 
mitigate this problem. I am not too crazy about the color of asphalt emulsion.
Ed