I would like to create a mirror polished concrete floor in a contemporary kitchen - it's done a lot in warehouse conversions. How's the best way to do this as builder is putting screed down next week. I have underfloor heating too. I don't mind if the floor has small cracks as this adds to the look. It's 47m2 minus the units' area. I presume a power float is used just before the surface is rubbed up? Does it take long?