on the job im at in there is a 25mm dip in the slab (finished floor is polished concrete) over about 2m right in the middle of the kitchen, concreter's did a great job on that 1. on another job the concrete was up and down about 30mm here 23mm there another 35mm over here, had to get some1 to grind the slab down before we could build the walls. and were not talking sh*tty metricon jobs, were talking 1mil and a 1.6million dollar renovation