HI group,

I bought a house built in 1925 which has oak floors. They are not in
the best shape, with cracks and weak spots (funny the home inspection
didnt really call it out as a problem). Additionally, it has been
refinished as many times as it can take so we are going to replace
it. There is no subfloor, however. My question is: could you have
the new floor installed right on top of the old floor (making it
become the subfloor) or would you just have both installed brand new?
Or just a new floor without a subfloor?

This is for two rooms on the ground floor that is over a basement.
Currently we hear the boiler and see through cracks, so I'd like
something very sound and as sealed as possible. Not married to any
particular type of wood so if one type is better I'd love to hear
about that too.

Thanks in advance to this very generous group!