Neighbors upstairs Tubs are draning slowly.
My neighbor has a split level that the h.ba and m.ba are draining slowly, no bubbling noises as they drain which would suggest some type of vent blockage or blockage. There was a 1/2 ba. added down stair main floor 2 years ago, but everything else is draining great. I'm going on roof and snake the the vents next.The new 1/2 ba. has a 1-1/2 vent. Any suggestion?