Foundation under second floor bump out living space

[wormdunker]

I have a walkout home, off the back we have a 4 season living space that extends off the second floor.  The space measures 11' w x 13'7" d.  We are considering enclosing the space underneath adding foundation and framing up to the bottom of the second floor room.

Reasons?  more space, although it is not a large space it is space nonetheless.  The house is 2700 sq ft. The basement is completely unfinished, in fact I gutted it as we are doing some additional remodeling.  Second by adding the room beneath we feel like we will gain more efficiency for the second floor room.  It is cantilevered out of the house  so the floor is cold in the winter.  Adding space will fix that.  The room also over looks our back yard which is forested so the view is great it will likely end up being my office......so I have that going for me.

So my question is to any concrete guys here, what kind of approx expense am I looking at to add a foundation and floor?  If within budget i will also be looking for a contractor to do the work. 

[derbier122x]

I was looking into getting a 5 inch thick pad poured on the side of my garage. Not gonna happen for us and the 600 ft project. They wanted 6 to 7 bucks per Sq ft everywhere I called. I would guess a foundation is more expensive.