I need to know if this is acceptable with as much wet venting as I'll be doing off a 2" stack that will tie into a 3". I can also take the 2" straight out the roof and not tie it in (that would be easier).. I also wish to thank everyone that's helping me, you guys are a rarity these days:

If the shower is located in the floor above the sink and tub, you can't wet vent the sink and tub with a drain pipe from a floor above. All fixtures that drain into the wet vent need to be on the same floor level.

So I'm back to my original configuration. No biggie. I'll vent the shower seperately wiith a dry vent I'll tie into the 3" stack in the attic and the same for the stack running from the sink below. I still want to use 2" in case I decide to scrap the old cast iron vent for the toilet. I either need to remove or build it up higher as it terminates right outside an upstairs window which is another big no-no.


This was my original configuration to vent the second downstairs bathroom and the one upstairs:



I can also go straight through the roof for the vent downstairs and not tie it into the 3".

i'm not quite sure what you are doing? but if the shower enters the stack slightly higher than the toilet, it needs no seperate vent as long as it is within a certain distance.

Unfortunately the shower enters the stack about a 18" lower. I thought about using a double sanitary tee, but I still have to get the 2" vent from the 1st floor tied into a dry portion of the 3". The shower might have enough drop to attach to the side inlet of a double san-t. I still would have to use a 3x2x3 san-t higher above to attach the first floor vent. The price comes out to being about the same. $12.50 ($8 for the double san-t, $4.50 for the 3x2x3 san-t), $13 for the way it is now. There's a 3x2 wye that's already glued on the stack to catch the shower trap (from a previous install) and I'm not counting that since it's already there. That 2" vent is going to be tricky to tie in anyway.

After looking at all the elbows and pipe needed, I think I would be ahead to just go through the roof with flashing. $5 for the flashing vs. $6 in elbows, $8 in pipe, and $4.50 for the 3x2x3 san-t. Okay. I'll cut out the wye and replace it with a coupling (use it for something else later), replace the 3" san-t with a double. Attach the sink to the left and the shower to the right.

I only thought I could pick that thing up for $8? My source was wrong. What's the going rate on one of those?



Edited 1 times.

$17 was the cheapest I could find a 3x3x3x2x2 san-t. I think I'll just scrap connecting the first floor to the 3" vent:




If I can find a san-t with a 2" rt side inlet for under $9 I might go with that.

That "vent" you have "jumping arounf" the toilet tee and connecting to the shower does NOT "vent" the first floor.

Bad illustration. No the vent from the first floor does not connect to anything now on the second floor. It's going straight out the roof ffrom the first floor.