I am putting a washing machine/dryer stack duet in a closet in my home. We are on a concrete slab. Where I am installing is the main stack and is 3" cast iron. Opposite the wall is the toilet in the main bathroom. I purchased an Oatey PVC saddle for 3" PVC with a U-bolts to fasten to pipe, and a gasket made for cast iron pipe. The inlet is for 2" PVC, and the riser for the washing machine is going to be directly beside the washer. What do I need to use to drill or cut the cast iron pipe for proper drainage?

You don't do that.

You install a PVC san tee and two no hub couplings. Remove a small section of the CI by using ratchet snaps or similar tool.



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good advice.. but, my code requires the san tee to be 'like' material. so a no hub cast iron san tee is required.

it would also take the least amount of pipe removal.

And make sure that something supports the stack above where you cut. If not done correctly, you can make quite a mess. You pay for the plumbers knowledge once, or pay twice for him to repair your lack of knowledge.

I thought about the stack above the cut. That is why I only wanted to drill the hole. Thank you for the information, I could have mucked this up pretty well!



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A safe bet, is to contact a licensed plumber in your area and ask them for an estimate for the job and what it entails. If you use the wrong equipment, not only will you cause damage to the cast iron and be required to do the job accordingly to local codes. I am sure that is what you want to do.

Best Wishes

Hire a Plumber is the best advice yet. You definitely do not want to damage the Cast Iron that very well may be rusted and weakened and can crack vertically...Bad news.