I am building my second outbuilding on a dry laid stone foundation. My building department (North Greenbush, Rensselaer County) had no problem with it whatsoever. Sills on the first one are white pine (white pine heartwood is moderately rot resistant). The one I am working on now has all-heart white oak. Jack's new barn, being written about in the last two issues of Timber Framing, also has white pine sills.
Similarly, my TF addition and garage have white oak sills (2" for the garage, 8" for the addition) on poured concrete. Again, the building department had no issues with the lack of PT.
I don't know what the building department would say if I wanted to build a larger structure or house on a dry stone foundation...
FWIW,
Dan
