Rough In Question for DWV

[homeowner80]

In need of some advice for a rough in for my new 2nd story bathroom toilet and tub/shower.

I was wondering if the 2 inch tub drain could drop into the 3" toilet line which is running roughly 15 inches to the 3" main stack that will go thru the roof?

Would I need the 1-1/2 or 2 inch tub drain vent if it was run directly into the main 3" stack?

I have 12" floor joists that run perpendicular to the toilet sewer line and it is kind of tight where the main 3" stack goes thru the end joist. I am allowed to do 4" holes thru the joists, but I am thinking of running the toilet sewer line under the joists and framing out the ceiling to hide it. Any thoughts or suggestions?

 

[Plans Or Bust]

In need of some advice for a rough in for my new 2nd story bathroom toilet and tub/shower.

I was wondering if the 2 inch tub drain could drop into the 3" toilet line which is running roughly 15 inches to the 3" main stack that will go thru the roof?

Would I need the 1-1/2 or 2 inch tub drain vent if it was run directly into the main 3" stack?

I have 12" floor joists that run perpendicular to the toilet sewer line and it is kind of tight where the main 3" stack goes thru the end joist. I am allowed to do 4" holes thru the joists, but I am thinking of running the toilet sewer line under the joists and framing out the ceiling to hide it. Any thoughts or suggestions?

My best advice is to tap in a sanitee to the main stack below the toilet if possible. Otherwise you could remove the 3” sanitee the toilet is on and replace with a tee (or a twin, if you order it) sanitee and a 3”x2” reducer.

Short of that you can tap into the nipple that connects the closet bend to the sanitee and use a sweep wye, a small riser, and a 2” sanitee, but you would have to get pretty lucky to be able to have your vent land under a bottom plate.

Think about if the closet bend or fittings ever has an issue and you would have to shut down the toilet and the shower just to address the toilet issues. Best to separate them and make sure to check code on venting distance for the bath/shower.