Hello -

Trying a re-post of a previous question, this time including a picture. There is no current access to an existing direct vent within the room/area. Trying to understand if I can use a confined space vent for the four applications (Toilet/Shower/Tub/Vanity). I've used them before for an island sink, not sure about toilet/shower/tub.

Appreciate any help anyone can offer.
Ryan

I would suggest to the designer to put the hand sink near the 3" pipe coming down from the upstairs toilet. Then you horizontally wet vent your new bathroom group and bring a new 2" vent up though the first floor. Then tie into the existing vent stack or vent for that toilet or run it VTR.

Option B: AAV (air admittance valve) can serve as a vent for the whole bathroom group in some codes. Again if the bathroom was horizontally wet vented one single vent could be installed.

Have you thought about installing a backwater valve for this new bathroom group to protect against a city sewer or main line back up?



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I have not thought about a backwater valve previously, but now considering it. Can you vent thru a side of the house, or does it have to be thru the roof? Problem w/going thru first floor would be opening an upstairs wall (ranch home). Not desirable for sure, but realistically not a horrible option. I'm not sure I understand either were an air admittance valve would fit in such a configuration.

Appreciate any guidance.

I've seen drain pipe and vent pipe on the sides of homes and businesses around here. Some blend in nice and other's not so much.

I think it will lower the appeal of your home to have a vent outside and then up the exterior of the home. But if you don't care or don't plan to sell your home then go for it. All plastic pipe is sensitive to UV light. Keep that in mind too.

An AAV is code allowed in some places. Find out if your AHJ is OK with it. The AAV can be installed in the new bathroom wall above or near the vanity with a louvered cover to allow for air in.



Edited 1 times.

depending on how much floor you take out, you will need 2 possibly 3 vents.
i) shower
2) toilet wet vented thru lav
3) tub.

IMO: no direct vent = no bathroom addition

perhaps, down the road, you will find time and money to do a proper install


MERRY CHRISTMAS

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

AAVs are tolerable for relieving a negative pressure, but do nothing to relieve the positive pressure in a basement when the upper level plumbing is used.