The answer is, it depends. I do this for a living. There could be a variance. It could be a pre-existing, non-conforming structure. It could just be violating code. We, the body politic, just don’t have the facts. Let’s assume that its a variance or pre-existing, non-conforming structure. In such case, the use of the building is fine…until there is a casualty, then you will likely be unable to rebuild the structure as it currently is. Instead, any new structure would likely have to comply with code. As always, talk to your local real estate attorney.