There was a cool OddLots episode recently where they talked to a guy who does Office to Residential work and some of the complexity.
One thing he talked about, which I didn't know anyone did, was to actually cut through the ceiling/floorplate of buildings to basically "donut" them.
This is necessary because many office floorplans are huge with modern HVAC and when converted into residential you end up with either undesirable or illegal apartments due to lack of windows/egress/etc.
Apparently they've done it a few times.
Of course only some buildings can support this, given the layout of the supports, mechanicals, etc.
One thing he talked about, which I didn't know anyone did, was to actually cut through the ceiling/floorplate of buildings to basically "donut" them.
This is necessary because many office floorplans are huge with modern HVAC and when converted into residential you end up with either undesirable or illegal apartments due to lack of windows/egress/etc.
Apparently they've done it a few times. Of course only some buildings can support this, given the layout of the supports, mechanicals, etc.