I own apartments and have had problems for years with tub during shower leaking to downstairs. We have changed gaskets in overflow and drain, recaulked around outside of tub, nothing had helped. A past employee used a toilet to tank gasket to fix the problem in the tub. Problem is I don't know how he used the gasket. Can you help? Thanks

If the leak only happens during a shower and not during tub use it is eithera leak above the mixing valve or at the place where the wall and tub meet. Put a 5 gallon bucket under the shower head and turn on the shower, shut it off just as the bucket fills. If you see your leak active it's the mixing valve. Remove the handle and escutcheon plate, use a flashlight to obesrve the valve when you turn the water on. The leak could be right where the verticle pipe exits the valve upward toward the shower head or it can be running down the pipe from the 90 degree drop ear elbow at the top.