[Cob] foundations and waterproofing

[Amanda Peck]

Sounds reasonable, unless you are trying to build something like Wright's 
Falling Water.

So a good, well drained gravel foundation with rock starting at or just 
below ground level would be fine in most climates?
...................
Peter and Marlin replied to Lorraine and me (snipped)
So my question is why do you need to waterproof between the foundation and 
the cob ?

>If you're talking about Cob (clay / sand /straw) I WOULD'nt use a 
>waterproof membrane as that's where moisture will get trapped and do MORE 
>damage by trapping moisture at that point. Clay has a marvelous way of 
>absorbing moisture and then releasing it and the condensation/wicking would 
>come and go, based upon temp/humidity. Instead I think if you're very 
>worried about moisture getting up into the cob (from especially concrete) 
>I'd put a good, very sticky layer of mud.