Ryan asked a question recently, in the message board, about using Caliche in cob.  I too have a layer of caliche in my soil, about 3 feet down under the ‘adobe dirt’.  Caliche is a form of calcium carbonate that cements together other materials like gravel, sand or clay. It’s generally found 3 to 10 feet under the topsoil in arid or semi-arid regions. The term caliche is Spanish and is originally from the Latin calx, meaning lime.

I wonder if it could be used as a replacement for sand? Pulverized caliche could add color or brightness to your finish plasters; kind of a natural lime or whiting.  I haven’t experimented too much with this material as an additive to cob.  I doubt it would have a negative affect.  Let us know if you have experimented with caliche and cob!

Update:

Thanks to Jim for pointing out The Center for Maximum Potential Building Systems, Caliche Report [PDF]

The Cob Builders Handbook, You Can Hand-sculpt Your Own Home, by Becky Bee is a great book about cob building. I recommend reading this book along with The Hand Sculpted House for beginning cobbers.   It’s a fun read and it’s accessible, in part, online at weblife.org/cob.
Of course, you can order the full book in paper form from Becky‘s web site.  While your there check out her book You Can Make THE BEST HOT TUB EVER! for making a wood fired bath tub.

On Friday I went to  AdobeUSA 2009 Conference in El Rito. It was hosted and co-sponsored by  Northern New Mexico College.  A college that offers a certificate program in Adobe Construction.

Presentations that stuck out for me were Pallet Building by Dafyd Rawlings; Carole Crews speaking about traditional ways of working mud; and Tim White‘s talk on plaster increasing energy performance, sometimes by 10%.  Between presentations I snuck off to take some pictures…

View Photos »

Jon Nunan is writing  a book about alternative homes. He sent me a series of questions that I am answering here…

When did you begin your project?
May 31st,  2007.  For this article I’m speaking about Oasis Pod 1. I’m also working on Oasis Pod 2, a.k.a SolUnit.
Oasis Pod 1 is a low cost alternative / natural building hybrid.  It is off the grid. Meaning it’s power comes from the glorious light bulb in the sky, it’s water is harvested off the roof when it rains, and it’s heat, or some of the heat,  is produced via passive solar design – heat from the sun, with propane backup.  The roof is pretty conventional, though the walls are mostly natural building materials.
Continue Reading…

Geological materials co-mingling into a perfect earthen mixture.  This photo was taken where a fine, light colored sand lays next to adobe clay. It’s delicious to think how these materials are so raw and how somewhere in there mother earth is making a perfect mix!
I’ve used this fine sand mixed with regular adobe dirt, red clay and kaolin clay. Making a variety of different colored alis mixes or earthen paints.

Alis Recipe

60% kaolin clay
40% whiting, sand, and or mica
* Add a cup+ of wheat paste per 5 gallons