Our company out-grew one of our existing data centers and we chose to buy an existing one to move into. However we really tore that one out from ground to ceiling and built it back out to our specifications and needs. We completely removed the raised flooring and installed chimney racks that sent the warm air up and overhead to the air conditioning units on the side. We were able to save significant money on cooling costs this way and add racks as we need them as the overhead slots are ready for installing new racks at will. The space is much cleaner and most energy efficient than the old data center and now we have plenty of room to expand.