I have two of these. One in my commercial dealership shop, that goes up and down 20+/- times a day. We put diesel trucks up it, but if Im working on anything that requires manhandling the truck I toss tall jack stands under 4 corners. Nothing on anything lighter/shorter though. I think the concrete measures between 4-5'' when I put it in. The other one is at home in my shop and currently holds my 68 camaro up out of the mice's reach. The concrete it is in is roughly the same as above, 4-5'' and was the original floor in my shop that burned down. Probably shouldnt have put the lift back in that concrete, but meh, its still there and doing fine.