Can I join a new 1 1/2" OD wall arm with p-trap to an existing 2" OD stubout? I have everything dry-fit with a Marvel threaded PVC stubout adapter, but when I'm looking at it, something just doesn't look right. Any comments will be appreciated.

should work...

What was the original intended purpose of the 2" stub?

Bathroom vanity sink drain.

steve, it is not a 2 inch stubout.
it is a 2 inch OD.

The only 2" OD PVC pipe I've seen in a house was for central vacuum systems.

may be the stub out is not a pipe but a fitting so the OD is the fitting's OD?

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Click on image link for clarity. Hope this helps. If anyone can advise as to posting images, I'll be grateful.



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that is plain old 1 1/2 inch pvc pipe.
the fitting you have is exactly what you need.

The in-wall pipe is 1 1/2" schedule 40 and the trap arm is 1 1/2" tubular. As Packy stated, good to go.

Thank you, gentleman, for your time and consideration. Your comments and advice are much appreciated.



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you should finish the wall before putting on the trap adapter to avoid having to cut a larger than necessary hole, also it will be difficult to put on escutcheons behind the supply valves. Will it be a pedestal sink or a vanity cabinet?

OP: you are good to go, finish the wall after testing complete

sum and OP;

bell escutcheon for the waste + split escutcheons for the supplies will be good to go





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

Yes he can use split escutcheons for the supplies. However, if he is using a vanity cabinet he would have to cut extra large holes to fit over those soldered on valves anyway.



If I went through this much trouble to open up the wall to expose everything, even if it's DIY project I think there are a number of simple things he should consider improving which are difficult to do once the wall is closed back up. For example:

(1) That 90 PVC elbow could be a long turn elbow. Cost $2.

(2) the copper supplies are not strapped in anyway, one is held against the back of the wall with shim between the drain and supply. I would be tempted to do something to add in a piece of lumber somewhere. Or Use I don't know what they are called those copper plates with holes all along that you nail to the stud face to stabilize and align the pipes and just solder the pipe's outside to the plate.

(3) I would also eliminate the soldered valves, change it to either a threaded or compression connection, and use quarter turn valves instead. In the process he can cut the holes just a tad bigger than the pipe and use regular escutcheons. Otherwise if he ever has a broken valve he will be a challenge to unsolder those valves inside a tight wood cabinet.



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there ya go again ... talkin' like a plumber



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