Abstract: A foundation system comprises a prefabricated set of concrete forms for a manufactured building that is already on-site and in-place. The concrete form set includes standard-length sections that bolt together immediately below the rim of the manufactured building. The inside sidewall of each concrete form is tilted back toward the outside perimeter and the outside sidewall is set vertical within both end frames and any intermediate frames. Anchor rings are provided at the ground level of each frame to accommodate four foot lengths of rebar that are driven through the rings into the ground to spike the concrete form to the ground. Jigs are used to suspend anchor bolts in the open tops of the forms between the two sidewalls. Once the concrete pour has been made and allowed to set, the concrete forms are unbolted and the ground spikes withdrawn. The tilt in the inside sidewall allows the concrete forms to be easily popped off.