From my vantage point in the crawlspace, it appears as if my vent stack is leaking. The bottom of the vent stack is in the crawlspace, and it connects to the only toilet in the house. I say it is leaking because there is visible water on the stack leaking from above where the toilet would drain into.


I have a house built in the late 1950's and I have a cast iron vent stack. My bathroom sink drains into the vent stack, above where the toilet empties. The vent stack appears to be leaking and I believe there is a clog in the house main drain about 10 feet down the line.

1) Is it rare to see cast iron vent stacks last this long?

2) If it is a leak in/around the joint where the sink drain connects, and I remove the clog, what can I use to patch up the leaky vent stack?

[1) Is it rare to see cast iron vent stacks last this long?
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No! I have cast iron stacks over 555 years old.

2) If it is a leak in/around the joint where the sink drain connects, and I remove the clog, what can I use to patch up the leaky vent stack? It would depend upon where the leak is. If the pipe has rotted out then you must replace the pipe. If it's from the threaded adapter that threads into the sanitary tee then that's a different repair altogether. You must first ascertain where the leak originates from. Good luck, Tom