[Cob] mortar for rock walk

[Charmaine Taylor]

Deborah--You can use 1 parts hydrated  lime to 6-8 parts soil raked up 
and spread the lime around the soil, mixing in with a hoe, lay in the 
rock and water lightly, tamp if possible.  The lime will harden up the 
soil and stabilize the clay particles so it is not muddy, and will act 
as a soft mortar.  In Japan they call this Tataki, and   they use 
Magnesium Chloride..which I know little about, but is a salt type 
product I am imagining.

In any case, I have cast stepping stones etc which hold up for a few 
years of just clay+ lime and sawdust + a little sand, and also poured a 
BIG step, embedded with pretty rocks.  it is  finally eroding after 
three years of severe rains on it in an exposed area.

In general it takes just 2-4% hydrated lime mixed into  clayey soils to 
stop the from being muddy.

you could also use the cut off ring from a tire as a form or permanent 
step circle, and fill the inside with loose pebbles, cast a cob 
stepstone, etc.

here is one I made:
http://www.northcoast.com/~tms/steptire.jpg

PS just can back from the World Thin Shell  Conference in Lorane OR, 
lots of ferro cement spraying onto domes/ forms, but there was 
potential for light weight application of cob mixes to air forms I 
think. Many people were introduced to the idea of natural building, 
lime use, and got to see papercrete samples, fiber blocks, clay 
plasters etc and were genuinely interested in them as finish plasters.  
  Overall most were men who like the big toys for spraying a home in 
just a few days...

Charmaine Taylor Publishing  books at dirtcheapbuilder.com
PO Box 375 Cutten CA   95534 707-441-1632
www.dirtcheapbuilder.com  www.papercrete.com


On Jun 19, 2004, at 7:12 PM, Deborah Denmark wrote:

>  This summer I would like to lay some rock (collected from my garden) 
> for a walkway to pretty up our current place.
>
> I am fairly sure cob would work temporarily and eventually erode away.
>
> What would be best to use that would last longer, hold the rocks in 
> place and NOT have concrete/cement in the mix.
>