So I just did a little quick math on the weight of my machines and even if I round up a little for a safety margin, I'm only looking at 15 000lbs of machines spread out over the whole space, so I guess it's a little less than 15lbs/square foot. Of course on top of that would be regular things like work benches assembly tables hand tool storage etc. However, even the heavy machines only have 6 square foot platforms and that doesn't consider yet having a stack of green timbers in there for cutting.