We bought a 73 yr. old house with 2 bathrooms, back to back, almost mirror images. Our ceilings are 7 1/2 ft. One bathroom is 5x7 (263 cf.) with a small shower and toilet and the other is 6x7 (315 cf.) with a tub and toilet. Previous owners installed ceiling vents, but they were just vented to the attic (no ductwork) The fans were very quiet, but I knew they were working because a sheet of tp would stay on the grills.

Because we have very small eaves and a slate roof, I had a slate roofer come out to install vents on the roof. He connected 4" flexible duct to each fan and to the roof vents he installed - which are directly over one of the bathrooms, but the run for each duct is less than 10'. Now, we can hear the fans a little better (not loud, but you do hear something, but the toilet paper will not stay on the grills any longer. Any thoughts as to whether something was done incorrectly? I would have thought the suction would be better now, not worse?