[Cob] Water glass sealant

[Ocean Liff-Anderson]

Waterglass is Sodium Silicate (not potassium silicate), and Kiko  
Denzer and I have used it extensively on the restaurant cob  
features.  It can be brushed on after the cob wall/cob plaster is  
bone dry.  We used a 50% sodium silicate/50% water solution.

I have found that Sodium Silicate works well for mildly wet locations  
- areas where the wall is subject to no more than blown mist.  But  
driving rain will soak through eventually and harm to cob, plaster  
will flake off...

Limewash is the best waterproofing you can give to cob - that's why  
the cobs in Wales are still here, 500 years later!

Ocean


On Jul 20, 2007, at 2:18 PM, Stephanie Enevoldsen wrote:

> Hi Cobbers,
>
> Has anyone had luck with using potassium silicate (waterglass) as a  
> sealant
> on outdoor exposed cob?
>
> -- 
> Stephanie Enevoldsen
> www.hobbithomes.ca/terracobba
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