I have a turn of the century Victorian. The foundation is rock solid,
as in literally made of rocks, and solid. And yes, the subfloor is
wood, which has been refinished and is being used for the "real" floor
now. The wood is gorgeous; prettier than most of what I see in new
hardwood floors. At some time, someone closed in the old side porch
with big sheets of glass and turned it into a spa room. Unfortunately,
the glass is not removable and turns it into a bake oven in the summer.
My first big project will be turning it into a 3-season room.
Luckily, they kept much of the character of the old side porch, so that
will be the theme.