I live in Cleveland, Ohio, and would like build a two-car garage with a small apartment above it behind my house (there's already a driveway in place) for my mother to live in. I'm imagining a garage of about 22' x 20' with approximately 400 sq. feet of living space on top. My partner and I had a well-regarded garage contractor (Angie's List) give us a guesstimate of $80,000. Another contractor would not give us an estimate, but insisted we needed an architect in addition for the apartment design and suggested we ask him how much it would cost. Doing casual internet searches I've found that $80,000 is on the high end of normal. Without going too cheap or cutting corners, what is your estimate for the least we can spend to build?
Yvonne B. ~ Cleveland, Ohio,
Yvonne, contractors can be reluctant to quote construction estimates based solely on square foot measurements, and for good reason. More often than not, it is the finished details and construction materials which most effect building costs, and not the size of the building. That being said, a well-built and finished garage can be built for $45-$65 a square foot and an apartment living space should be able to be completed for around $100 a square foot.
Keep in mind that although you want to build a small apartment, you will still have some of the construction costs associated with a full-sized home. For example, you still need to have a bathroom, kitchen, and HVAC system and these costs can be considerable. While you certainly save money on flooring, siding, electrical, insulation and painting by building a smaller building, there are some building costs which you will not avoid, no matter the size of the building.
You may be able to save some money by not working with an architect, and instead use a contractor who has some stock plans for a garage/apartment design. A talented builder should be able to use some stock plans to build you a garage which complements your home and meets your specific needs. Perhaps you should consult with some contractors who work in the Cleveland area to see if any of them have such plans available. Good luck with your project!