Q. I'm using a new floor finisher, who's known as the best in this area. He saw that we had installed oak and ash floors over rosin paper and insisted that we should have used 30-pound felt. He says the rosin paper will degrade over time and won't provide any cushion between the subfloor and the hardwood. Is he right? We only use felt in old houses where the basement is really moist.

A.Wood flooring contractor and consultant Howard Brickman responds: Rosin paper, bad; 15- and 30-pound asphalt-saturated felt, good. Installers love red rosin paper because it is really cheap and easily covers up the dusty subfloor, making it easier to slide the wood flooring into position during installation. But those reasons don't have anything to do with the quality of the completed wood floor.

Asphalt-saturated felt, on the other hand, performs a number of functions: It retards the flow of moisture from the underside; it increases friction between the bottom of the flooring and the surface of the subfloor, resisting lateral movement during shrinking and swelling; and it provides some adhesion between the bottom of the flooring and the surface of the subfloor, helping to eliminate squeaks when the flooring is nailed properly.

And don't forget that many manufacturers and wood flooring trade associations require you to use 15-pound asphalt-saturated felt or building paper; failure to use it may be regarded as a defect if you get a complaint.

Finally, at some point new houses become old houses, and since you can't be certain about long-term moisture conditions, why not build for the long run?