Your in luck, I build houses (thanks Milamber!) I can honestly say 2x6 floor joists would never pass code in this country
but since it hasnt fallen down yet its likely ok, especially at 12" oc. I'm assuming a plywood or osb flooring over the joists. The plywood is stronger material. Anyway back to your question, while I doubt your weights would cause the whole floor to crash down onto the first floor the legs of the weight bench possibly could put a hole in the floor (and cause a bit of a hazard to you if you have to slam the bar down). An easy solution is put something under each leg, thereby distributing the weight. A 2x block, or if that makes it too high a 12"x12" piece of plywood under each leg should take care of any fears you have about taking the house down [img]smile.gif[/img]