Wet venting layout for bathroom

[ECCsimmons]

So I've been doing a full remodel of our bathroom given water damage from the last owners. I've gone down to the joists & studs. Now I'm looking at drainage/venting solutions. I've got a few plumbers coming by in the next few weeks, but wanted to get a broader range of opinions.

I have a single standard vent of 2" going up through the roof at this point. I'm trying to avoid tearing out the ceiling, as it's the only damn thing in the bathroom that was salvageable. So I started looking into AAV (eeek, not liking what I've been reading) and wet venting.

So I went through and read a ton of code, and tables, and really get lost when they start talking about maximum distances from certain portions of the system to others based on pipe sizes. So here's a rough idea of what I would like to do, but I'm not sure if the piping sizes & distances will be up to code.

 

[hj]

The tub/shower will either have to be piped differently or get its own vent.

 

[Sponsor]

 

[Terry]

The tub/shower will either have to be piped differently or get its own vent.

That was my thought too.

 

[ECCsimmons]

Is that because it would technically be the most downstream fixture on that vent? How would you recommend re-piping it?

 

[hj]

No, it is because the water closet discharge is flowing past it.

 

[ECCsimmons]

So theoretically could be Y'd into the drain of the lav instead of the main drain? Not sure how that'd be accomplished at this point, but just throwing it out there.

 

[MKS]

Have a look at this image,upc, from this site.

The toilet enters last when not half bath.
Yes there are limits the lengths of the runs. This is technical and I do not have an explanation or the numbers to hand. But understand in some way.

 

[ECCsimmons]

So it seems like a better option would be something like this. I'm thinking I'm going to have to increase the diameter of some of the pipes to allow for the extended distance between the toilet and the wet vent.

 

[ECCsimmons]

I guess the real question I have to clear up is how I'm interpreting "Distance of a trap from vent". Is this the distance from a trap to the WET vent, or is this the distance from the trap, to the start of the wet vent (where wet connects to dry vent). So basically is this distance for my tub/shower calculated at ~8-9', or is it simply ~5'.

 

[hj]

It is the distance between the trap and the vent, whether wet or dry. The toilet enters WHEREVER it has to, NOT necessarily last.

 

[ECCsimmons]

Okay, so from both of your comments I have to assume the toilet can enter wherever, it just can't discharge past another fixture that is being wet vented upstream.

Thank you for the clarification on the trap to vent terminology. So it would seem to me that with that distinction, the shower is technically only ~5' from trap to vent which is fine with a 2" trap, and the toilet is roughly 11' from trap to vent which doesn't exceed the max of 12' using a 3" trap sloped @ 1 inch per 8 feet.