New 3/4 bathroom venting layout and questions..

[Simon Tseghai]

Hello Everyone!
We are putting in a new 3/4 bathroom and moving the washer/dryer to the other side of the room. There was already a drain and vent at the original washer location so we'd like to tap into that for drainage and venting. The bathroom plumbing wall isn't continuous to the roof to install a new roof-vent and the joists won't let us reach the vent pipe directly (in walls above floor) without tapping into it in the crawl space. There is some room in the crawl space under the floor for plumbing. Could you please take a look at my sketch and let me know what issues you see? Some of the plumbing is already laid out but i want to make sure it's vented properly. Any help is greatly appreciated!!

 

[Simon Tseghai]

This is what is looks like in the crawls space. Thanks again!!

 

[Sponsor]

 

[Simon Tseghai]

 

[wwhitney]

I would say you can't use a loop vent for other than an island sink. I believe you're in GA, which uses the IPC? Then you are allowed to AAVs.

Your washer standpipe is going to have a conventional dry vent, that reconnects to the blue stack on the left of your elevation drawing, which receives no drainage from a floor above? If so, that's fine.

You'll also need an AAV for the laundry sink (although since it's right next to the washer, can't you just dry vent it the same way as the washer?).

As for the bathroom group, if you use an AAV or dry vent at the lav tied back in like the washer does, the lav can wet vent the shower and the WC. To do that, you need to keep the lav, shower, and WC drains separate from anything else until they all join each other. You pick a (2% sloped) elevation for a horizontal drain under the joists, the shower trap is at the upstream end of that horizontal run (no drop between trap and drain). Then the lav drain joins in within 8' of length / 2" of fall from the 2" shower trap. Then the lav/shower drain joins the WC drain, and now the combined lav/shower/WC drain can join the main horizontal branch.

Cheers, Wayne