I am looking for feedback on the costs of building an elevated house with sitting area below vs. a separate sitting area adjoining the main house. The assumption being that the areas are of equal size.

In the roof merits threads two posters commented that it would be cheaper to build a single level home and have a separate covered area for outdoor sitting, car park etc. This is counter intuitive to me and I am wondering if there is something I am missing.

I know the stairs might be a pain in the ass when I get older and I know the separate area will consume garden space but for this thread I would like to stick to the cost difference.

My thoughts:

On the plus side for the elevated house I am thinking most of the savings are in the roof. Other than a slight extension to cover stairs up and down there should be little or no extra costs on the roof. There might also be some savings on services as the water and electric would be more centralized.

On the plus side for the separate area, you would need more footings but they could be smaller (not sure if this is really a significant savings). Columns might need a bit less steel as well as there is only the roof to support as apposed to the entire house plus roof. I guess you also save on a set of stairs.

Other than this I can't see much price difference, as both areas will need equivalent flooring, paint, furnishings, etc.

Comments?