I’m going to take Thanksgiving week off to gut our only bathroom in our house. Just wanting people’s opinions in regards to replacing the stack. It’s cast iron pipe from about 1958. Our house is a rambler, unfinished basement, and the venting is all galvanized pipe. I was consisdering removing the cast iron from above the basement floor to where the galvanized pipe starts above P-trap in the bathroom sink. It would be roughly 8 feet of pipe to remove. Would I be better off leaving it? It seems prone to plugging, and the exterior of the pipe looks a little rough from leaking that happened before we owned the house. It seems to me that replacing everything with PVC while I’m redoing the bathroom would be a good idea. I could also get rid of the can trap on the shower drain at the same time. Obviously it’s hard to give me your opinions without seeing it, but I’m curious the pros and cons of leaving the cast iron pipe and replacing it with PVC to the basement floor. Any suggestions as always are appreciated. Thanks.
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Replies
We usually don't replace cast unless there is a problem. If it is prone to blockage that can usually be handled with either a good drain guy and a snake or a water jet that will clean the sides of the pipe. But cast iron in general doesn't wear out.
However if you are set on replacing it, not really a tough job. And not particularly expensive. Tie in at the cast on the floor with a Fernco coupler and tie into the vent with the same. And replace everything else. Probably won't have $300 in the whole deal. The galvanized is a poor drain material but ok in my opinion for vent so I wouldn't replace it. Just my thoughts. DanT
Hi Doc,
I just did this exact job on my house. Get a cast iron pipe snapper!!! You can rent one for +/- $30 a day around here.
I started just under the roof and took it down in roughly 3' sections all the way to the basement floor. It took me about an hour.
We had the new stack and vents roughed in by lunch time.
Did I mention get a pipe snapper?
One thing cast iron has over plastic is the noise factor. Cast is quiet. Plastic tends to let everyone in the place know what you're doing at any given time. In general, if the cast is in good shape, I'll just replace the parts necessary while leaving the stack intact and as has been noted, use ferncos to transition the two materials together.
To add to what Homewrite said, my plumber always installs cast iron stacks form first to second floors specifically for the reason H-R mentions. I do new construction.