I have an old large shed I'm trying to get back into shape. The building is about 50 years old and 16'x48'. One of the long sides had sunk in the middle by about a foot, giving that side a bit of a 'V' shape. I've actually jacked this side back to level with a few beams and am trying to figure out how to support it permanently.
The original foundation was a shallow concrete perimeter, about 1' wide by 2' deep, right below the shed walls. There was a single course of cinder blocks placed on top of the concrete, and the walls built on top of these. The concrete seems to be in good enough shape on 3 sides but has completely crumbled on the side with the sunken middle.
My idea is to build a short retaining wall, about 2 feet out from the raised side, to level off the 'V', fill the inside with rubble/gravel, and set the shed back down on it. I feel like the wall could be simple as it doesn't need to hold much back - maybe some PT 6x6s or 6x4s driven a few feet into the ground every 4 feet and then PT 2x8s behind them. Does this seem like it would work? Is there a better way?