For sure it can be retroed but as is was all I was asking. Plus it would be awhole lot cheaper to have had is set up to accept a second floor in advance. Not trying to stir the pot, only wanting to understand how some are expecting this to be three floors. Actually once grow rooms are set up it would be impossible to get the materials and equipment in to build over the grow rooms....major contamination if not a major fire hazzard from overhead welding