Really small addition and foundation?

[Tex]

I have a garrison colonial (standard 2nd story 12" overhang of 1st floor) and would like to make the 1st floor even with the 2nd floor by adding a wall. But not increasing the living space of the 1st floor. I will however be putting a bay window in the wall.

My question is regarding a foundation. Can I dig out a 4ft deep trench

12" wide beside the existing foundation and fill it with concrete? Or do I just need to dig a couple of 4' deep holes and add some posts to support the new wall and window? Thanks Jeremy

[Edwin Pawlowski]

You can make either way work. Your local building inspector will tell you what needs to be done though.

[Goedjn]

Ok, then what *ARE* you trying to accomplish? If all you're doing is making space for more insulation, you shouldn't need more foundation at all.

[Tex]

I think that I could use angle braces and tie everything back to the foundation, if I weren't putting a bay window in the wall then I would be more apt to do that.