Building Extra Floors

[Account Closed]

Hi all, has anyone developed an additional floor on an existing one-story MF or SFH? It would be extremely helpful to hear the process and costs associated with similar projects. Thank you!

[Evan Polaski]

@Account Closed, I have sort of done this.  I have purchased some bungalows that had unfinished second floor space, tore the roof off and built a true second floor.  I say sort of because, the existing second floor had hip roof 6' tall ceilings in center, and was built on 2x8 (I believe, since its been a while) floor joists.  This was also part of a full gut remodel of the first floor too, so cost was not exclusive to adding second floor.  All told, job cost me $275k in 2017.  Probably would be $400k for the same work today.  

Process: good architect and engineer, good GC, permits.  Then tear off roof and trusses in place, frame new walls, we had to sister all floor joists for second floor.  Current code calls for 2x10s and we had 2x8s, so doubled up all joists.  Add steel to main beam in basement to help carry new weight, frame new interior and exterior walls, new roof trusses, new roof, siding, windows, all the finishes.

Other things to consider: where are stairs going in first floor, if none are already present, are there any zoning issues with additional height, can sewer system support any additional beds/baths, etc.