I'm (slowly) building a darkroom in my garage. The garage floor is a slab on top of which I'll build a subfloor. The house itself is pier and beam. My thinking is that the best vibration-free place to put my enlarger would be to build a very heavy "island" and put huge (8-inch? 12-inch?) industrial casters on the bottom and put a layer of bricks or cinder blocks in the bottom to weigh it down. I would think a well-build subfloor on a slab would be MUCH more vibration free than the wall of a house where Alec-the-precocious three-year old is frequently jumping up and down and running. Also, the wheels would let me swing the enlarger head forward for wall projection and move it to and fro to get just the right size for huge enlargements.