Removing a single sink and installing two vanity sinks. There is an existing vent and drain as shown. My question is, do I need to intertie the waste and vent lines as shown in red or can I leave them unconnected? Thanks....
Bathroom sink remodel venting/drain question
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Removing a single sink and installing two vanity sinks. There is an existing vent and drain as shown. My question is, do I need to intertie the waste and vent lines as shown in red or can I leave them unconnected? Thanks....
Each lav needs to be vented, or the traps will siphon.
Revents take place 6" above flood level of the fixtures served. In most cases that means 42" or higher off the floor
Code wants to see 2" for two lavs, and you can do 1-1/2" if it's one lav.
Vents go through the roof to vent out sewer gas.
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There is a window between the sinks so I can't get the vent 6" above the sinks/42" above the floor. I have two other ideas to throw out...
The first would be to wet vent per the attached drawing. If this is ok, can I plumb the sink drains together as indicated by the red dotted line?
The second idea would be to use an AAV. If I went with the AAV, do I need to use one on each sink or can I get by with one between the sinks?
Which would be preferable, assuming they are both acceptable?
The first would be to wet vent per the attached drawing. If this is ok, can I plumb the sink drains together as indicated by the red dotted line?
The second idea would be to use an AAV. If I went with the AAV, do I need to use one on each sink or can I get by with one between the sinks?
Which would be preferable, assuming they are both acceptable?
Cacher_Chick
Test, Don't Guess!
In WI, you can run both 1.5" trap arms to stacked sanitees on a 2" vertical drain. The upper sanitee must be 2x1.5x1.5, with the lower being 2x2x1.5.
The trap to vent distance on 1.5 pipe cannot exceed 5 feet.
The trap to vent distance on 1.5 pipe cannot exceed 5 feet.
Plumber69
In the Trades
Code is stupid sometimes. There's no way in hell a double vanity will siphone another sink.
Cacher_Chick
Test, Don't Guess!
I would not agree with that. The code is written to work over the test of time. 10 years from now when the piping has buildup and some guy is dumping buckets of water down the sink for whatever reason, the improperly plumbed drain could siphon the downstream trap.
It would be great to have some clear pipe and fittings to mock up some of these layouts and shoot video, so people could see what is happening.
Thank all for the helpful replies.
If I understand correctly, the solution would be to use two stacked sanitees on top of the existing drain, vent out the top of the sanitees to the existing vent. I may have to offset the drain through the floor or use a short horizontal tailpiece on the far sink in order to keep the trap arm distance to 5' as it is slightly over 5' as is....Is this ok? Thanks again.
If I understand correctly, the solution would be to use two stacked sanitees on top of the existing drain, vent out the top of the sanitees to the existing vent. I may have to offset the drain through the floor or use a short horizontal tailpiece on the far sink in order to keep the trap arm distance to 5' as it is slightly over 5' as is....Is this ok? Thanks again.
Stuff
Well-Known Member
Please provide a picture and more ideas may come. Might be able to take the vent at a 45º to the left and catch the drains closer to the middle.
Stacked san-t's won't help solve your trap-to-vent distance. AAV on the left sink might be the best option.
Stacked san-t's won't help solve your trap-to-vent distance. AAV on the left sink might be the best option.
Instead of a short horizontal trap arm and/or slight drain offset through the floor, perhaps better just to use a 2" trap arm from the left sink to the sanitee....The distance is about 65".....
A 45 vent take off won't work as there isn't enough vertical space.
A 45 vent take off won't work as there isn't enough vertical space.
Cacher_Chick
Test, Don't Guess!
If you can move the vertical drain to bring the vent to trap distance down to less than 5', and the vent remains vertical, that is a correct installation under WI code.
A 2" trap arm on a lav is a bad idea, because the lav does not flow with enough volume to scour the 2" pipe.
Instead of two stacked sanitary tees, could I drain each sink into the opposite arms of a double sanitary tee?
Cacher_Chick
Test, Don't Guess!
To do that, a double fixture fitting is what you need. The vent still needs to be vertical to at least 42" above the floor, so based on your previous diagram, it is not clear how you would to it. There should also be an accessible cleanout for the drain.
Was thinking the following....Existing drain through the floor is offset a few inches, sinks drained into double fixture fitting, vent out the top of the dff and over to the vent at a 45 or greater angle....Any suggestions for where a cleanout would best be located?
Cacher_Chick
Test, Don't Guess!
The drawing showing both sinks draining into one horizontal pipe makes me think you might not get it.
Each trap must have it's own trap arm draining to the vertical stack. This is why the stacked sanitary tees work here, because it will be a straight shot from the trap to it's tee on the stack.
Assuming you have shelves or drawers or something below the sink, the trap arms can be offset horizontally to the back of the cabinet.
Each trap must have it's own trap arm draining to the vertical stack. This is why the stacked sanitary tees work here, because it will be a straight shot from the trap to it's tee on the stack.
Assuming you have shelves or drawers or something below the sink, the trap arms can be offset horizontally to the back of the cabinet.
No, look at the lower part of the drawing with the label "TOP VIEW". From the front view, it looks like the drains are the same but one is behind the other, they go into opposite arms of the double fixture tee....
Cacher_Chick
Test, Don't Guess!
I see it now. You can do that, but you wont fit it all in there. It is always good to eliminate unnecessary bends. Long sweep bends or 1/8th bends must be used on the horizontal.
The cleanout can be above or below the trap arm commection on the stack.
Thank you very much for all of your help....Here is a clearer sketch. The cleanout is below the double fixture tee. Also, I have shown an offset tailpiece to the p-trap on the left sink to get the trap arm length to the 60" mark. Can you tell me what the code limit is in WI for this offset? Thanks again!
Cacher_Chick
Test, Don't Guess!
I cannot really help there because it is not done that way. We would run another vent up the left side of the window and tie them together above, or we would keep the trap coming off the tailpiece and run the trap arm 45 degrees relative to the back wall to shorten the oal. 60"' is the longest production vanity top around, so as long as the drain is at the right edge of the cabinet, the distance works.
By the way, I have a bath with a window over the vanity, and I really dislike it.
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