Enough room for 2" drain

Old 06-28-18, 02:37 PM
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Enough room for 2" drain

lol. draub... meant drain.

a plumber told me to run my new kitchen sink connection into the wall, then down thru the sole plate and vent up thru the top plate. If I run a 2" drain, it goes from the front of the plate and hits the back of the rim joist. Is it OK to use 1 1/2 then use 2" after it goes thru the plate and turns at the elbow?

Last edited by Zorfdt; 06-30-18 at 06:21 AM. Reason: Fixed title typo
Old 06-28-18, 03:06 PM
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Typically a kitchen drain is 1 1/2. As long as you don't go from larger to smaller you should be OK. But lets hear from the pros.
Old 06-30-18, 06:39 AM
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Kitchen sinks have always been good at 1.5". But I think there may have been a recent code change to upgrade to 2" for new installs. I've had a few plumbers tell me this, but I haven't found the actual code change. I've seen it done as 1.5" through the floor, then changing over to 2", but again, I'm not certain.

The vent can certainly be 1.5"
Old 06-30-18, 07:31 AM
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The vent can certainly be 1.5"

That may work, but in many parts of the country a 1 1/2" vent will ice over in cold weather. I had a good plumber tell me many years ago that ALL 1 1/2" vents should be increased to 2" just before going through the roof deck.

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