5Step 5: Asseble the form on the roof
Satisfied with the form I reassembled it on the root cellar walls. A nice snug fit, supported by 3 vertical 2×4’s on each side. (Not shown in the picture are 8 pieces of 1/2″ plywood approximately 6″ x 23″. These were installed after the plywood sheets were added. They are used as extra reinforcing ribs by wedging them between the plywood sheets and the top of the 2×4’s.) Next, the plywood, a sheet of plastic and lots of 1/2 rebar. Lots of rebar. Rebar is cheap, so why not? If this were a flat 4 inch slab, the calculated load rating is around 250 pounds/square foot. More then enough. But it is arched, and up to 5 inches thick. Also the rebar extends into the walls a foot, and are cemented in place. Not sure what the load rating is now, but it is certainly more than adequate.
