We are adding a new master bath and the existing vanity area is being removed and the wall behind the vanity area will be the opening into the new master bath. A 3" ABS vent pipe runs up through that wall and out of the roof. This vent served the old bathroom and vanity area, which is being converted into a closet.

What is the best way to seal this pipe once it is cut off flush with the slab? Also, what is the best way to seal the old toilet flange?

I want to make sure that there is no chance of leaking sewer gas through either of these as they will be under the new floor.

Thanks for any help and advice you can give!

Keith

They make a cap that can be used and installed with ABS adhesive.

Chuck

A cap will stick up and I think you will be using this area as a walkway, right. You can put in a plug and the flush cut the nut part off. GRAINGER APPROVED VENDOR Cleanout Plug, 3 In, MPT, ABS, 180 Deg F - ABS Pipe Fittings - 1WJE3|1WJE3 - Grainger Industrial Supply What will be the new flooring material? You can float this spot with seal leveling cement to get it smooth

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You can put in a plug and the flush cut the nut part off.

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No need to do that, Simply purchase a recessed cover Like the one shown. Good luck, Toim

You aren't just worried about sewer gasses, Keith, but a sewer backup that could flood the basement if these pipes don't get capped properly!

In this case, I would go with schedule 40 ABS cap (see image). Here, Keith wants to chip out around the pipes until he can cut the pipes to below the concrete by 2 or 3 inches. He can use an inside pipe cutter to cut the pipe and then he can cement/cap the pipes using the schedule 40 caps. With proper planning, this will leave about an inch between the top of the cap and the finish floor and that can be filled in with a hydraulic cement to finish the job.

Keith can now lay the floor and never think about these pipes again... ;)

I would not just stuff a rag in the pipes and then lead them in as people used to do years ago!

Mark