I would like to install a ¾ bath and I cannot easily access existing vent stacks or run a dedicated stack without disturbing existing finished areas of the home.

Can I use air admittance valves to vent a single sink, toilet, and shower inside the bathroom and if so can they all be located under the same vanity? If that is not the best idea, is it possible to vent horizontally through a foundation wall as an alternative? The proposed location for the bathroom is above a crawl space and the foundation wall adjacent to the project could conceal a stack if one is permitted under a deck approximately 24” from ground level.

What is the proper way to accomplish this project?

qquote; What is the proper way to accomplish this project?

No good way to answer without seeing the "project".

Got ya. The project is top secrete but in general it involves placing a shower, sink, and toilet into a room where they do not presently exist…

Rephrase:

Can you install a ¾ bath without running a vent stack using air admittance valves?

If so, do you need one for each application or just one for the whole room?

Where is the best place to “stash” them?

If they are not desirable; why?

Are there other options? I have never used them…



Edited 2 times.

They are not the best way to go, but they are used all the time for situations such as this. I am speaking for my state where they are allowed though, I am not sure if Ohio allows them or not.

You typically would make the lav the last fixture being caught, run the drain into the bottom of the cabinet and place the AAV there.

With that being said, a vent through the roof is a much better system. It would most likely take an experienced plumber to accomplish this though. The AAV has the potential to give undesirable results "sometimes", but not too often.

I know, all of you that are going to critique how we wet vent in Michigan, but that IS how we do it and it works fine.

I'd like to add that Autovents, no matter what brand or design are mechanical vents and so they WILL fail.

Yes, if quality made and totally protected and in an ideal situation one might not fail for 25 years (although it could fail immediately or a week/month/year from now) and since venting is so important to protect the health of the inhabitants you hopefully will do all that you can to avoid them and install proper non-mechanical vents instead.

Non-mechanical as in properly sized and piped going all the way through the roof and only having to rely on the laws of gravity and nature and not something made by humans.

Not for a whole bath room of three fixtures. Do the work and do it the right way the first time with proper atmospheric vents.

- - - - - - - - - -

Retired after 50 years of plumbing and heating.

quote; Not for a whole bath room of three fixtures.

Don't go hyperbolic with your "prohibition". THey are often used for "whole bathroms of three, (and even more), fixtures.

The most common one sold is rated for 20 dfu's.

And even then most people are only using one or two fixtures at a time.

There is only one way to PROPERLY vent a whole bath and that is with atmospheric vents!

- - - - - - - - - -

Retired after 50 years of plumbing and heating.

We all agree with that RWP.

The poster was asking if he COULD use AAV's, and we said yes. We also told him that is NOT the best way though.

I COULD heat my house with space heaters if I wanted, but that doesn't make it right

Sorry where the system is understood. The need for positive relief, void.Yes the av is exactly the devise to use.