must the subfloor be covered with tar paper BEFORE hardwood floors are installed? my house is on a raised foundation and my wood subfloors are in okay condition. the installers did not use tar paper claiming i had existing hardwood flooring, which was my subfloor. "with our experience, when you have existing hardwood flooring, we do not use tar. if tar is used with existing hardwood flooring, it cannot breathe and over time, the floors will start to crack and push into each other, which in turn will cause the floors to squeak. this installation was not done on plywood, it was on existing hardwood flooring which didn't indicate moisture." is this true? there is moisture under my home in the crawl space and i'm concerned about water damage to my new floors. HELP!!

There are two reasons for the paper:

1. As a vapor barrier to help prevent moisture from coming through the subfloor and into your finish flooring.
2. To limit squeaks between the finish flooring and the subfloor.

The only reason to not use a felt layer would be it there is already one layer of felt there. If this new floor it going on top of an existing floor and that floor already has a felt layer under it, then you'd be better off to skip the felt. Otherwise, it should go in.