I have a 40 * 60 sq.ft split into two 20*60 house in the ground floor. I have planned to build a single duplex house (2500 sq ft) in the first floor. I just need your advice, is it advisable to build a duplex in first floor?.
If you have twin house of 20'X60' than I think it is possible to build duplex on first floor but for that GF house should be with good foundation.
I had the similiar issue for constructing duplex house over 2 storey house. The advice given to me is put concrete pillars around the house and let the duplex sits on those pillars and getting support from ground floor house.