Q.I was asked to look at a job where the homeowners have issues with loud, creaking floors. The floor system appears to be 3/4-inch-thick subflooring on 9 1/2-inch-deep wood I-joists 16 inches on-center. As far as I can tell, the subfloor was not glued to the I-joists and shifts when the joists deflect, causing the noise. The joist bays are filled with batt insulation, which slightly helps to muffle the noise between the floors. Would adding resilient channel and a new drywall ceiling below the floor system substantially reduce the noise, or will it be necessary to pull up the carpet and subflooring, then glue the panels to he joists to stop the problem?

A.Bonnie Schnitta, owner of SoundSense, an acoustic consulting firm in East Hampton, N.Y., responds: It's always preferable to stop a problem at the source if possible, so in this case the ideal approach would be to pull up the carpet and padding and screw the subfloor securely to the joists. (This may not be practical if the carpet can't be...

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