[Cob] too much clay

[Damon Howell]

Kristen,
	The higher the clay content, the more severe the cracking as it  
dries. 2-3 days in full sun will usually dry it completely, but if  
you have a lot of clay you will see cracking within an hour. There  
are benefits to having lots of clay in the mix: it's more water  
resistant, holds heat better than sand, and it's easier on the hands  
and feet. The downer is it doesn't have good compressive strength in  
case you wanted a heavy roof. As far as falling apart when it gets  
wet, it takes a long time for completely dry clay to get soaked that  
much, far longer time than a clay/sand mix. Then you put the straw in  
there to bind it all together and it doesn't go anywhere easily.

Damon in Georgia