I bought a house with wood flooring. The roof was in a bad condition (thatch) and a lot of rainwater got on the floors before I rethatched.
Do I sand the floor, then polish it?
Don’t do anything until the wood has dried out, and settled back into place. Heat the place a little warmer this winter, and heat the basement or crawl space under the floor. When the wood’s moisture content reaches 6-8 % (or whatever the indoor equilibrium moisture content for indoor wood is in your area is) then you can certainly sand the floor and refinish it. Polish or wax is not a wood finish. Contact a local wood floor mechanic or cabinet maker to find out what the EMC is in your area, and test the wood with a small hand held electronic moisture meter (www.leevalley.com prod. #99N15.01).
For that matter it is far better to have a professional sand the floor only and do the finishing yourself. That’s the fun part anyway. But if you are really lucky the wood will settle back down in place, and you may only need a little surface sanding and a touch up. Please read my floor maintenance article available at the top of this web page in the search box. The second part of the article deals with old finishes, and how to identify them and treat them.