Hello. I'm installing a toilet/lav/shower in my basement (concrete slab).

The toilet will drain through a 3 foot long 4" PVC pipe @ 1/4" per foot and tee into the existing vertical 4" cast iron main, which is vented through the roof.

The lav will drain through a 4 foot long 2" cast iron main, which is vented through the roof.

The lav will drain through a 4 foot long 2" per foot and wye into the toilet's 4" PVC pipe. The lav will be vented through the roof via a 2" PVC pipe.

The shower will drain through a 4 foot long 2" per foot and wye into the toilet's 4" per foot and tie into the lav's 2" PVC via a combo wye and 1/8th bend fitting.

My questions are:
1) Can a combo wye and 1/8th bend fitting be used in a vertical application as shown in the sketch?
2) Will the shower and toilet be wet vented by the lav's 2" PVC pipe that runs to the roof?

I would greatly appreciate any help and advice. Thank you.

Hello. I'm installing a toilet/lav/shower in my basement (concrete slab).

The toilet will drain through a 3 foot long 4" PVC pipe @ 1/4" per foot and tee into the existing vertical 4" cast iron main, which is vented through the roof.

The lav will drain through a 4 foot long 2" PVC pipe @ 1/4" per foot and wye into the toilet's 4" PVC pipe. The lav will be vented through the roof via a 2" PVC pipe.

The shower will drain through a 4 foot long 2" PVC pipe @ 1/4" per foot and tie into the lav's 2" PVC via a combo wye and 1/8th bend fitting.

My questions are:
1) Can a combo wye and 1/8th bend fitting be used in a vertical application as shown in the sketch?
2) Will the shower and toilet be wet vented by the lav's 2" PVC pipe that runs to the roof?

I would greatly appreciate any help and advice. Thank you.

(1) Yes it can.
(2) Your group will be wet vented by the lav vent.
Just the way I like to see them! Simple and uncomplicated ! Good luck, Tom

Great. Thanks for the quick reply Tom. I appreciate your help.

I have another question. Should some type of sleeve be wrapped around the PVC pipes where the pass through the concrete floor? If so, what type of material should I wrap around the PVC pipes?

Thank you very much for your help.

Great. Thanks for the quick reply Tom. I appreciate your help.

I have another question. Should some type of sleeve be wrapped around the PVC pipes where the pass through the concrete floor? If so, what type of material should I wrap around the PVC pipes?

Thank you very much for your help.

We install a "closet wrapper" on all slab toilet stub ups. This is a styrofoam wrapper about one inch thick. This prevents the pour from blocking in the stubup and after removing the wrapper we have room to install a closet flange. We don't wrap the other drainage pipes. However we do install Armoflex pipe covering on all copper water pipes coming up through a cement slab. Cheers, Tom

Sounds good. Thank you.

I have one more question (I think). I have the option to install an inside toilet flange or an outside toilet flange. Is there any benefit to installing one or the other? Would an outside flange work better because it provides a larger cross sectional flow area?

I really appreciate your advice.

Sounds good. Thank you.

I have one more question (I think). I have the option to install an inside toilet flange or an outside toilet flange. Is there any benefit to installing one or the other? Would an outside flange work better because it provides a larger cross sectional flow area?

I really appreciate your advice.

If I had my druthers I'd use the outside flange for the reasons you describe. However if you have to chip cement to install one I'd go for the inside one. Good luck, Tom

Stub up with 4" pvc and then use a 4x3 flange into the 4" this will allow you to pour right to the
4" closet riser and will also make anchoring the flange to the floor easy
I also recommend that you use a flange that has the stainless steel ring