Laundry Room Vanity Drain Connection

[Justin83]

Good evening, folks.

I am replacing the vanity in our laundry room. The tail piece, p-trap, and wall tube for the old vanity was all metal, connecting to a metal stub at the wall (see photos for a visual). The new faucet comes with a PVC tail piece and I purchased a basic polypropylene p-trap kit to make the connections.

With the stub coming out of the wall being metal and the p-trap being plastic, what is the correct way to address this? I've seen folks use Fernco couplings, but if using that here meets code, I'm not sure I have enough length on the metal stub coming out of the wall to grab ahold of.

I'm a little hesitant to loosen the nut on the wall side of the wall tube, but this could just be my ignorance. If I loosen that nut and remove the metal wall tube, can I simply insert the polypropylene wall tube from the new p-trap kit into metal stub coming out of the wall? If so, do you use a metal nut or a plastic nut for that connection? I would tend to shy away from mating metal and plastic threads together.

Any advice would be greatly appreciated!


Thanks,

Justin

 

[Reach4]

I'm a little hesitant to loosen the nut on the wall side of the wall tube, but this could just be my ignorance. If I loosen that nut and remove the metal wall tube, can I simply insert the polypropylene wall tube from the new p-trap kit into metal stub coming out of the wall?

Yes.

If so, do you use a metal nut or a plastic nut for that connection? I would tend to shy away from mating metal and plastic threads together.

That is not a pressure connection, so the nut does not have to be torqued down much. If you try the plastic nut, and don't like it, it is easy to change out with a slip-joint trap. Plastic will not corrode.

 

[Sponsor]

 

[Justin83]

Thanks for your response, Reach4! I just want to make sure I understand you correctly on a couple of things.

Yes.

If I remove the metal wall tube and insert the new PP wall tube into the existing metal stub, I could then just reuse the existing metal nut shown in the photos, correct?

If you try the plastic nut, and don't like it, it is easy to change out with a slip-joint trap. Plastic will not corrode.

Two questions:

1. Sorry, I’m not quite following you here. The kit I have only has two plastic nuts (one for each end of the p-trap). Are you suggesting I get a plastic nut for the wall tube and give that a shot?

2. I believe the Oatey kit that I have uses slip-joints, so I’m not following you on the comment about using a slip-joint trap if the plastic nut doesn’t work out.

Thanks for your patience, forgive my plumbing ignorance!

 

[Reach4]

If I remove the metal wall tube and insert the new PP wall tube into the existing metal stub, I could then just reuse the existing metal nut shown in the photos, correct?

You could reuse that nut, but a new one would not be very expensive.

I would lightly lubricate the washer under the nut with silicone grease (not silicone adhesive).

I believe the Oatey kit that I have uses slip-joints, so I’m not following you on the comment about using a slip-joint trap if the plastic nut doesn’t work out.

I am saying that the nut at the wall could be new plastic or new metal or the old metal. I expect that would be fine, but it does look like you might have some deposits.. If any nut did not work out for some unexpected reason, it would be easy to swap out the nut, just as it is easy to swap out the the trap.