Constructing my first home, from cob.

G'day everyone! I live in Alabama USA, and this is going to be my first house. I live on around 150-200 acres of wild forest land, and am curious if any of you are could give me some advice on building with cob. The dirt here is red to the core, and I've yet to find a good clay pocket for building cob. I'm using the book The Hand-Sculpted House as my guide, written by the people from The Cob Cottage Company. They're from up north, though, so if any of you could give me some advice about how I should tweak it to suit the conditions of the weather and the natural building materials in the south, I'd appreciate it!

How have you been determining your clay content?  Shake bottle test?

I would think you won't need tweaking past figuring out your soil and what if anything you'll need to amend it.

Where I'm at, I dig down past the top soil, then through the clay/top soil mix to the clay layer that seems almost impossible to dig... this is where the clay is.

Some places the clay is near the surface and other places it is 4+ feet down.

If you go to a place, that is a rain runoff ditch, sometimes the rain will cut a ditch down to the clay for you.

where at in alabama are you, out of curiosity? I'm close to Huntsville.



David

Quinn, the climate in the part of Oregon where the Cob Cottage Company is wouldn't really qualify as a northern climate.  Summers won't be quite as hot and humid as where you are (although they do get plenty hot), winters are normally quite mild.

Seems like on that amount of land you ought to be able to find a seam of clay soil somewhere, but if not, what other building materials could you find on your land?  Seems like the best things to plan to use for building are generally what you have available.  Better to build with logs or stone, for example, if that is what you have, rather than buying in clay where there isn't any.

Kathleen

     Excavating companies are always looking for places to dump clay. Sometimes you can charge a little.  Silt and clay can look very similar so make sure to test before committing. Silt is not a good binder!  Wheather you are building rock walls, a driveway, building berms ,paving with recycled bricks or contemplating a wood chip burner, check to see if you can get your supplies delivered by dumptruck for free.  I have had luck sourcing all of the above in quantities far beyond my needs.

I'm in Georgia, of course I have almost nothing but red soil here too.

But this stuff is about 50/50 clay/sand, is it really that different were you are? You should definitely do a bottle shake test. I did it and thought it was all red clay, but after looking closely that was just a little bit of clay still on the sand, and it turned out to be about 50/50