New basement bathroom and vent tie in

[maxguy]

Hey Guys,

I'm working on installing a basement bathroom into a relatively new home (2009). The builders installed rough ins for a toilet, shower/tub (1.5") and vanity but provided no easy options for venting the sink or the shower (come to think of it I'm not really sure where the vent for the toilet rough in is...). Really there appear to be only 2 options.

1. Tie into the 3" vent for one of the first floor bathrooms. The problem with this option is there is so little pipe exposed that I don't believe I would be able to tie into it at all. It's between joists, where the pipes could barely be cut and if they could be there would be almost no pipe left to install fittings onto.

2. Tie into a 2" wet vent used by the other first floor bathroom. Currently that vent services a single toilet and the vanity. I'm planning on tying the basement shower and vanity into that. To do that I would install a 2" tee-y into the wet vent, rotating the tee-y so that it is say at 45 degree oriented upwards so that the drain for the vanity would not enter the vent for the basement fixtures.

I have attached a diagram of my proposed connection. I expect it will work but have no idea if it would meet code. Any thoughts? I'm located in Ontario.

Thanks guys,

 

[Stuff]

Don't know Ontario code but showers generally need to have a 2" drain. Tubs are OK with 1.5"
Lots of times you can get away with wet-venting the whole thing through the sink. But need to upsize to 2"
Can't figure out from your drawing what is existing and what you are adding, what is vent, what is drain.

 

[Sponsor]

 

[maxguy]

Thanks for the reply Stuff. Apologies for the unclear diagram. Here is another that hopefully is better. Lines that have black slashes in them are existing.

 

[Stuff]

That is clearer.
You are not allowed to share a wet vent between floors/bath groups so that won't fly. You need to tie vents in 6" above flood level of highest fixture and they need to be dry.
Find out if you are allowed to use an AAV (air admittance valve) as that would be the easiest solution to your venting issue.

 

[maxguy]

Thanks Stuff. I guess I'll look into an AAV and I'll check further into what would be involved with tying into the venting on the first floor (certainly opening a wall, but it's in a closet, so not too bad).

 

[Wrenched]

Hey maxguy, do you have any contact with the builder or with neighbours in houses built by the same builder?

Typically if a bathroom group is roughed in for future use in a wood frame single family dwelling, it's piped for the w/c(toilet) and the shower to wet vent through the lav(hand sink). There should be no need to run more venting. There should be a 2" pipe (fixture drain/wet vent) between the lav trap arm connection and the branch drain connection with the w/c drain. An 1.5" vent should already exist in the wall behind the lav above the trap-arm.

Ontario has their version of the building code online, though it might be a difficult read if you are not used to reading codes.

Neither of the drawings would be to code.

AAVs are generally only allowed if no other options are available, and then not for w/cs. The authority having jurisdiction always has the final say.