Solid Hardwood, Engineered and Laminate Flooring - wood bathroom floor

My husband & I are redoing our 100+ yr old bathroom. We just found a beautiful hardwood floor when we tore out the the linoleum and would like to keep the wood floor exposed. What type of finish/sealant should we use and how many coats when we refinish? We have some knowledge of floor refinishing. We are mostly concerned about possible cracks in the sealant allowing water to penetrate in the future. The floor is currently in good shape. Our considerations for a finish/sealant are that the house is fairly humid, but we do have a good exhaust fan and the house does shift in the spring (would the shifting cause minute cracks in the seal?). Thanks! Noel

Noel you might want to try tung oil as a sealer coat followed up with 2-3 coats of oil based polyurethane. The tung oil will serve to "waterproof" the floor (including exposed cracks if saturated) and the polyurethane will further protect it and serve as a topcoat.Waterlox makes a fine product and gives some basic information on the uses of tung oil on their website. www.waterlox.com