I'd estimate a cost of from 50 to 100,000 per unit depending on level of finish, and what amenities might already be in place.

IE my building already had an elevator, fire stairs and corridor walls. There was also a lot of electrical services in place and some AC units were able to be re-used with minor modifications to the ductwork. Further, the corridors were in very good condition and only now am I considering replacement of carpet in them after sixteen years of ownership.

The PO paid for high quality carpet and we are still using it in some of the office spaces. We also took some carpet up and re-used it in living units in the bedrooms.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.