We are located in Louisiana and just started getting bids back. Definitely is coming back much cheaper to go up than out. Less foundation, less roofing, and less exterior wall product.

Up is cheaper.

Going up saves roof and foundation but often adds some exterior wall and adds a stair that takes up space on both floors unless it is over a basement stair.

If there is already a second level moving a space up will be cheaper.

I read a detailed discussion on this topic in the book Better Houses, Better Living by an M. Ferguson. (If I don't have the name quite right, it's close enough to help you find the book.) I enjoyed the book very much. He's a retired home inspector who wrote a whole book about things you want to avoid in your house. I do recommend the book. I had some difficulty obtaining my copy, but I would suggest that anyone building a house put in the effort to locate one.

He brings up quite a few points, including cost of land, size of foundation, space lost to the staircase, exterior vs. interior walls, cost of heating/cooling . . . I can't remember it all, but it was a detailed answer and very worth reading.

His conclusion: It depends upon circumstances.

Putting aside the issue of cost, do remember that an "up house" vs. an "out house" will bring you different benefits, which may mean more to you than the cost difference. An "up house", for example, is more likely to allow you to have windows on two walls in all your major rooms . . . but you'll have to deal with the staircase as you age. So don't make this JUST about money.

MrsPete

Thanks for the information on that book. I will have to buy one before we start the building process.

The author is Myron Ferguson and you can buy it on Amazon.

FWIW, there are a number of folks who comment in this forum who have as much or more expertise than someone who may have written a book.

Just remember that the advice is worth what one pays for, whether it's in a book or on this forum.

Owners still have to do their own due diligence.

Yes, that's the book -- when I originally became aware of it, it wasn't available anywhere, but then it popped up on Amazon after some months of searching. If it's available now, I suggest you buy it now.

I agree that many people here have great insight. I've learned ever so much from reading this board, and I'm very glad that I'm reading it well in advance of beginning our building project.

You're dead-right that owners must do their due diligence. What's true in one part of the country, or what's true for another person's needs may or may not be true for you or me . . . and since no one cares about my project as much as I do, it's in my own best interest to put in every bit of effort I can.