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A problem with giving advice on the use of natural materials (especially
soil : loosely called clay in many posts) is that their properties are so
variable.<br><br>
When I was making mud bricks I experienced almost no shrinkage with most
of my sub-soil, but I have a patch a few metres from my principal
source which does shrink noticeably. My soil made excellent
mud bricks but as far as I could work out with simple tests is only about
ten percent clay. Look up the composition of clay on
wikipedia and see what a large number of various compounds constitute
clay.<br><br>
The key to success is experimentation (and a bit of luck).<br><br>
Regards<br>
Lance<br><br>
<br>
At 08:04 AM 29/01/2011, you wrote:<br>
<blockquote type=cite class=cite cite="">Frank, shrinkage depends on a
number of factors and can range from between 5% all the way up to 50% for
certain types of clay. Furthermore, the amount of moisture in the mix
will affect the degree of shrinkage. That being said, as a
'rule-of-thumb' you can expect about 10% shrinkage in the clay content of
your mix. If the clay is mixed with cellulose matter such as wood chips
or straw, these will swell and shrink independently depending on the
moisture in the mix.<br><br>
My suggestion would be to try using two or three coats / applications
with each successive layer filling the cracks and shrinkage that occurs
in the previous.<br><br>
Regards<br>
Steve<br><br>
<a href="http://www.naturalbuildingsite.net">
www.naturalbuildingsite.net</a><br>
<a href="mailto:naturalbuilding@shaw.ca">naturalbuilding@shaw.ca</a><br>
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