Another consideration which may not occur to you is that most buildings are planned to take advantage of the maximum number of “zoning rooms” allowed by law. What that means is that if your renovation plans include carving out an extra room, you may actually be taking your entire building above the maximum number of rooms allowed by law. Co-ops do have ways of getting around this by inter-borrowing space. For example, if someone else renovated, turning two rooms into one, your building picks up that extra room for the building’s overall zoning room total and that extra room could be granted to you or another shareholder looking to add a room. Too often, a co-op owner with a studio decides to put up a partition, turning their apartment into a one bedroom. They think, “It’s a tiny change. Whose to know or care?” But thanks to the rules about “zoning rooms,” once again you may be taking your entire building over the limit. Worse still, even if you don’t get caught out initially, that extra wall will come boomeranging back to you when you find that rather than owning a saleable studio co-op, you now have an illegal one bedroom that no one will ever touch. And local fire departments also have ordinances against illegal partitions because they may change the ability for someone to escape from a fire.