I have a home that was built in 1929. In the attic is a 4 inch cast iron vent pipe for the second floor bathroom.
Over the years, condensation in the vent pipe has corroded the bottom of the pipe allowing moisture to drip into one of the upstairs bedroom walls. Cutting out the bad section of the pipe is difficult because of limited space to get a cutting tool to the problem area.
My question is, "is there a PVC patch or other type of material that I can wrap around the existing 4 inch pipe to stop the drip?"