[Cob] Soil Survey

[howard at earthandstraw.com]

I would make test bricks before I imagined that it was a problem.   I'm sure our ancestors had silt in their soil as well and it did not stop them.  I expect you will need to add the sand and straw and that the silt may not be a problem at all.  How much sand to add should be determined by making test bricks.   If none of them harden well then you may need to add some more clay but I doubt it.  I've mixed cob with a variety of soils and always managed to find a mix that would harden well and I know there was a good bit of silt in all of it as it is very common around here.



Howard Switzer, Architect
668 Hurricane Creek Road
Linden, TN 37096
931-589-6513
www.earthandstraw.com