Bathroom Venting Question - Swap Sink/Toilet

[mezz64]

Hello,

I'm in the process of some bathroom renovations and would like to swap the position of the sink and toilet. I think because of the minimal distance (~4ft) between the new toilet location and my vent I can move the toilet and orphan the old dedicated sink vent, but wanted to gather some input before I rip anything out.

This is the as-found arrangement. The main horizontal 3" length is just over 6 ft between the drain going down to the 1st floor and the vent going up through the roof.

And this is what i'd like to do:

Any feedback is appreciated. Walls are open so I can correct any past mistakes from the original builder in the 60s if needed.

 

[wwhitney]

For the IPC (in use in PA) your proposed drain configuration is fine. The sink drain/vent loop could be 1.5" rather than 2", since that drain section is not part of the wet vent, because of the 3" stack.

But I believe capping off an used 2" vent like you show is not best practice, as the dead end could accumulate water. That's obvious if it rises straight up to go through the roof, but could still happen through condensation. So it would best to remove all the vertical portion, either back to the 3" stack, or at least until it turns horizontal. Or you could keep it connected to the drain system, with the understanding it's not really acting as a vent for anything in your diagram.

Cheers, Wayne

 

[Sponsor]

 

[mezz64]

Thanks @wwhitney. The 2" vent is actually a separate galvanized pipe that has it's own roof penetration, it doesn't tie back in to the 3". I was planning on capping it from the roof to prevent any water getting in if the changes made sense.

 

[wwhitney]

You could do that, but I'd be inclined to fully remove it and patch the hole in the roof and in the presumed ceiling air barrier.

Cheers, Wayne

 

[Jeff H Young]

weigh the options and value. I might put some mastic and a no hub band with blind plug , I might be re roofing in a year or 2.
Flat roof thats hot mop or a tile roof I might not want to patch myself. but agree Id have some preferance to removing the vent