here is the general plan for the root cellar.
the U-shape on the top of the bags is a row of cement beam block that will hold the entire roof to the bags via re-bar pounded down into the earth bags. i opted for this instead of using bags to create my arch because i plan to pile a bunch of dirt on top of the root cellar and i believe this will be stronger. we'll grow some ground cover over the top of the root cellar and pump house. earth roof for the pump house plan will be shown at a much later date.