A. Every house is different but here are some typical ranges: For a full 2nd story on a 2000 square foot house, the cost can range between $150,000 and $200,000. For a partial 2nd story in the 500-700 square foot range, expect to pay $90,000 to $120,000, especially if there is a new bathroom upstairs. People are often surprised to find out that a new two story, 20’ x 22’ garage (with living space on the 2nd floor) project, can cost between $100,000 and $150,000. Q3.