Cob building foundation

It is time to start the foundation for my cob building.  The foundation is a critical part, besides keeping moisture from wicking up into the cob, it also is the stable platform upon which the weight of the cob will rest.  Wet dirt is very heavy!

With my two part design, I am afforded a bit of a luxury in that I can now complete the East wall completely before digging the trench and starting the foundation for the “U” shape wall. 

Laying out the first level of the cob foundation

After laying a bunch of pieces of “Urbanite” out on the ground, I began building the puzzle.  (See previous post for more on my "Urbanite" adventure.  The idea is to have each layer of rock solid before adding more.  Each successive rock should contact two or three rocks below it.  Additionally the width of the foundation should be slightly bigger than the width of the cob wall at its base, which is supposed to be slightly larger than the cab wall at the top.  I am aiming for a cob base of between 12 – 16 inches.  So I cut a piece of PVC pipe to 18 inches to use as a jig as I build the foundation…. A guideline if you will, for knowing about how wide I want it to be.  I also decided to use some “selective mortaring” using some reinforcement in the trickiest places, particularly along the edges.

Finishing the foundation

Once I placed the biggest stones for the first level I filled in the gaps with small stones and a bit of mortar in a few places.  Then I continued level by level.  TIP:  have a bucketful of “chinkers close by”, small stones of various sizes to use as wedges and supports to get the larger rocks even and steady.  The idea is that you should be able to walk across a level without any rocks moving.  I found an old piece of bent metal I stuck in a hole a rock to be hidden within the cob wall.  I got the foundation solid and about a foot above ground level and decided that was enough.

Temporary roof

I also installed the roof rafters on top of the main support beams and covered it in plastic.  My hope is that the temporary roof will keep the area dryer and possibly allow me to work in the rain. One of our outdoor cats shocked me by walking out onto the plastic!!!. For more pictures and the full story of this episode visit my nature blog.

Ticker

Mortar, lumber and joist supports for this stage $36

Total money spent so far $92

Total time spent so far: 25 hours

 Now it’s time for some mud-slingin!