Would adding in a 2” wet vent to the lav below the toilet connection be up to code for venting the toilet?

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Tudorrenovator

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Trying to salvage this layout, it’s very tight space. Can can I add a 2” wet vent as marked yp from the lav next to the toilet, under the toilet connection be up to code? The vertical stack is going up to another bathroom on a different floor so that can’t be used to vent.

Is there a better way to lay this out if that doesn’t work?

CB0353E5-19D3-46A9-B4CB-29DCB5F126B9.jpeg
 

wwhitney

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No, the WC vent has to be connected to WC fixture drain before or as that drain joins other drains. I.e. since the stack can't vent the WC, the WC needs to be vented before that. You could plug the san-tee at the bottom of the picture (not use it) and replace the horizontal LT90 on the WC fixture drain with a combo. Then if the dry vented lav drain comes into that combo, it wet vents the WC.

Cheers, Wayne
 

Tuttles Revenge

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Here is how I would install that. Replace the 3x2 San tee with a 3" Tee or WYE.

Wet Vented bathroom.jpg
 

Tudorrenovator

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No, the WC vent has to be connected to WC fixture drain before or as that drain joins other drains. I.e. since the stack can't vent the WC, the WC needs to be vented before that. You could plug the san-tee at the bottom of the picture (not use it) and replace the horizontal LT90 on the WC fixture drain with a combo. Then if the dry vented lav drain comes into that combo, it wet vents the WC.

Cheers, Wayne
Wayne you are the man. For education, would the below work as well? A long 90 to vertical, a sanitee with the 2” lav wet vent, then anther long 90 back to the stack?

CAF96CC0-7040-4CC6-AAAD-C78749306A9D.jpeg
 

wwhitney

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If I understand your photo correctly, that matches Tuttle's suggestion, which also works.

Cheers, Wayne
 
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wwhitney

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I can't quite keep track of your entire system across multiple threads and with only limited photos.

But for the downstairs half bath, where the lav and WC will ultimately join a stack carrying drainage from the story above, for wet venting you need:

- A dry vent for the lav. Under the IPC, this can be a 1.5" vent through the roof, or an AAV.
- The lav dry vent has to come off the lav trap arm within the appropriate limits--i.e. if the lav trap is 1.25", before the trap arm falls more than 1.25".
- Then the lav fixture drain (fixture drain = only one fixture on the drain) joins the WC fixture drain almost any way that drains are allowed to join (*). The vent for a WC isn't subject to elevation restrictions.
- Then the branch drain joins the stack.

Cheers, Wayne

(*) Because PA has adopted the IRC's plumbing section, there is a limit on horizontal wet venting--you can't join the WC and lav drains with a fitting (combo) where the lav comes in horizontally, the WC comes in vertically, and the outlet is horizontal.
 

Tudorrenovator

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I can't quite keep track of your entire system across multiple threads and with only limited photos.

But for the downstairs half bath, where the lav and WC will ultimately join a stack carrying drainage from the story above, for wet venting you need:

- A dry vent for the lav. Under the IPC, this can be a 1.5" vent through the roof, or an AAV.
- The lav dry vent has to come off the lav trap arm within the appropriate limits--i.e. if the lav trap is 1.25", before the trap arm falls more than 1.25".
- Then the lav fixture drain (fixture drain = only one fixture on the drain) joins the WC fixture drain almost any way that drains are allowed to join (*). The vent for a WC isn't subject to elevation restrictions.
- Then the branch drain joins the stack.

Cheers, Wayne

(*) Because PA has adopted the IRC's plumbing section, there is a limit on horizontal wet venting--you can't join the WC and lav drains with a fitting (combo) where the lav comes in horizontally, the WC comes in vertically, and the outlet is horizontal.
That’s a tough condition to visualize. So the combo approach you mentioned above works because both the wc and lav inputs are both horizontal, and the sanitee option works because the outlet is vertical?
 

wwhitney

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That’s a tough condition to visualize. So the combo approach you mentioned above works because both the wc and lav inputs are both horizontal, and the sanitee option works because the outlet is vertical?
Yes.

We'll skip the discussion about whether you could use a double quarter bend with vertical outlet. : - ) I'm unclear on that.

Cheers, Wayne
 

Tudorrenovator

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Yes.

We'll skip the discussion about whether you could use a double quarter bend with vertical outlet. : - ) I'm unclear on that.

Cheers, Wayne
Thanks! I’ll post a new thread about the original layout of the plumbing, since that’s a slightly different topic. I found an interesting photo and would like some feedback
 

Reach4

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Better to add onto this thread IMO.
 
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