Historic Home, sloping floors, new subfloor

I have a massive 1890 historic home project that i'm undertaking, and one of the core issues is that the floors slope dramatically, and not in any one particular direction. We're going to be removing the majority of the existing finish floor (no historic value), and putting in a new subfloor. Couple questions:
1. What is the appropriate thickness of plywood to use as a subfloor for hardwood? 2. Should it be glued and screwed, or just screwed? 3. If an outside contractor is performing this work, what is a reasonable average price per sft for demo of existing floor and installation of a new sub-floor, assuming that there's at least 3500 sft?
Any help is mcuh appreciated.
MH

I have a massive 1890 historic home project that i'm undertaking, and one of the core issues is that the floors slope dramatically, and not in any one particular direction. We're going to be removing the majority of the existing finish floor (no historic value), and putting in a new subfloor. Couple questions:
1. What is the appropriate thickness of plywood to use as a subfloor for hardwood? 2. Should it be glued and screwed, or just screwed? 3. If an outside contractor is performing this work, what is a reasonable average price per sft for demo of existing floor and installation of a new sub-floor, assuming that there's at least 3500 sft?
Any help is greatly appreciated.
MH

Old or not, have you a clear understanding of why they slope the way they do?

"Matt Harrigan" wrote in message
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Why do I get the impression you believe a new subfloor will reduce the slope? If so, how did you arrive at this conclusion?

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I would suggest getting a handle on the cause & remedy of the floor sloping.....this sort of thing usually points to foundation issues. Active or dormant? recent / ongoing / old?
This need to be done before you worry about R&R of the subfloor.
btw what's your joist spacing? previous subfloor sizing?
What's wrong with the subfloor that you're thinking about replacing it?
cheers Bob