Tile tar and removing plywood

Q: We’ve just recently bought a house dated somewhere around the early 1900`s, After removing the 30 year old carpet and the 40+ year old tiles we discovered the original hardwood floors underneath. The tiles seem to have been laid with some sort of tar or tar paper under them.

Is there anyway to remove the tar or what ever it is on the floor without destroying the hardwood and what is the best thing to finish them with?

Also, in the dinning room under the carpet they laid over top of the hardwood floors there is plywood nailed down on top of the hardwood. Question #2 Is there some way of removing the plywood and refinishing the floor without destroying it by removing the plywood, and will the nailholes be evident or is there some way of filling in the nailholes so they wont be seen?

A: Sounds like a nasty job. Can you determine if the existing “tar” covered floors are even thick enough to tolerate a sanding? That would be the easiest way to remove this mess. It is a tough job. It is quite likely that this adhesive has also seeped between the boards. My concern with using an oil based polyurethane is that the solvents may soften this run off and cause it to start weeping into the finish. Perhaps a good quality water based acrylic urethane would be a better choice in this situation. As for the plywood, a large wrecking bar is needed. There really is no way to know what you have under that until the ply is removed. These floors will also require a full sanding and finishing, and this is work best left to a professional. There are latex fillers that do a very good job of hiding holes and gaps that a professional floor finisher would have at his disposal.