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Cold air return & drain pipe

We remodeled a bathroom & I am finding conflicting info. Can a toilet & shower drain pipe run from 1st foor straight down through a cold air return (floor joists were panned)? Plumber did not drill hole in joist, the drain pipes run straight down and make their turns below the steel sheets (which are not in place).

Panning is not back up, and I am looking at this thing trying to figure out how I am going to re-pan the joists. All drain pipes have already been glued in... One of two things that has been giving me a headache.


Re: Cold air return & drain pipe

I'm not sure about the plumbing but have my doubts, I do know that electrical cannot pass through ductwork

Re: Cold air return & drain pipe

So far what I have found, but not sure if it is right, is that you can run piping perpendicular through the return, but cannot run it parallel.

The more I look, the more I think plumbing has to be cut out, drain pipes started, holes then cut into panning, panning installed, then glue and reinstall the drain pipes.

Re: Cold air return & drain pipe

You do not have to cut the pipe. Cut the steel in half at the pipe, install it and use a Z piece to mend the cut. Be sure to use a sealant like a duct mastic around the seams and around the pipe, top and bottom.

Re: Cold air return & drain pipe

I guess it's not acceptable to have a drain pipe cut through a HVAC return vent..

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