A two story house will save money on roof and foundation. But it will cost more to put up the exterior on the second floor. I would think putting up trim and painting is going to be more expensive for a two story vs single. It certainly will be a PITA when painting has to be redone. Not sure if you get charged more for the roof from going from one to two stories.
Another expense in a two story house is the stairs. Completely wasted space that cannot be lived in or used for much. The best that can be done is storage squeezed in around the stairs. Bathrooms are one of the expensive rooms in a house. You can put a half bath under the stairs but do you need a half bath? I know I don't.
If you figure that the stairs, including walls are four feet wide and 12 feet long, that is 48 sf. At $100 a sf that is $4,800. But that is only 48 sf on one floor, the stairs really consume twice that because it is on two floors. I think the brick for our house cost $5,000. I would rather have brick than stairs.
Another problem with two story houses is the complication of optimum room size vs cost. Building design is a compromise between cost and room size. For instance, in our house it would be nice to have an extra one foot of space in the utility room. To add one foot to the room, without taking a loss of room in another space mean we would have to add 32 square feet in the house to gain the 16 sf in the room. At $100 a sf that added foot of space cost $3,200. It would be nice for our closet to have another square foot but to get a couple of square feet in the closet would cost another $3,200. Adding another foot in our bathroom would cost $6,500.
When we balanced out the cost/benefit of this added space we figure it was best to spend the money elsewhere.
For a TWO story house the numbers would have DOUBLED because the square footage increase would have impacted two floors.
The first designs we had were two stories. To get room sizes we needed on the second floor would push out square footage on the first floor. This was space we did not need but it increased cost.
I don't buy the idea that two stories are always cheaper than one. I am dubious.
Our house is a single floor with a finished concrete slab. Waste plumbing under the slab with water supply in the attic. The plan is for this house to be our retirement home. Two floors are out for that purpose. All doors are 36 inches wide and the bathrooms follow the guidelines for wheel chair usage as much as possible. Our shower does not have a door, shower curtain or lip. You could get a chair in there pretty easily. Comes in real handy for cleaning out the beer making buckets. :licking:
Later,
Dan