The title is a bit misleading, as I wouldn't call this a true concrete countertop experience. Most of the concrete will be covered by an earthen pizza oven, and the rest of it will just be left rough - no finishing with stains or sealants.
I had a lot of fun designing the form for the concrete pour. The shape includes a hexagonal-ish extension, onto which the circular cob oven will sit.
I tied all of the rebar together with metal wire, and then raised the rebar up 2 inches using pieces of rubble:
After the pour:
The countertop extends past the sheathing and into the building, where it rests a lot of its weight on the floor joists. Here you can see it inside:
I had some leftover concrete, so I built a quick 8X8 box into which to pour. It will be a neat little block to use somewhere later on.
I am wrapping the house in tar paper, and then attaching metal mesh to provide an attachment point for a 2-3 inch layer of cob. The entire building will get this treatment, and then be covered with cob; a beautiful earthen plaster will be applied once the cob is dry. The tar paper is to avoid any problems with the cob drying out/ruining/warping the thin plywood (which I don't think will happen, but I can't afford to find out).
The combination of tar paper, firring strips, and the setting sun make the building appear very skeletal: