We remodeled our bathroom and are now finding that the tub is draining very slowly. Tried plunging, hot water already. Seems to have made some difference but, not draining anywhere near as fast as it was prior to the remodel.

One thing that they did during the remodel was to make a slight re-route of the vent stack for the bathroom. I would say they moved it (by cutting in a new section of pipe) by about 2 to 3 inches.

The rest of the drains all work well. No issues with toilets either. Could the stack change affect the tub? Or, is it possible that some stuff got loose during the remodel and is now clogging the drain? Drain line is steel - not copper or plastic. Hose was built in 1949.

Thanks for any help.