If you’re talking about the garage, I don’t see a problem with that. It’s built to park vehicles in. The floor joists are 2x6 at 12” centers on top of four 4x6 runners, two of which are where the wheels would run. If you had perfectly level flat ground, just as it comes would be sufficient. My pad has 6” of slope as you can see. The blocks it’s on now are temps, running perpendicular to those 4x6 runners I will be laying graduating crossmembers of 2x6, 4x6 and 6x6 supports every 4’. I’ll post pics of that later.