Attachment 45417

I plan on moving the 1.5 inch sink drain from the floor to the wall. Will I need an additional vent that isn't there now?

Yes, unfortunately all sinks require an individual vent. I see that the old sink didn't have a vent, but as you suspected, that wasn't right...do your job right and add an 1.5" vent.

What kind of sink are you planning on installing...a pedestal sink, by chance? If you are installing a pedestal sink then stub the drain out of the wall at 20" to center of the pipe from the FINISHED floor.

Back to you...

Mark

I agree and it's a good idea to replace that trap, it was likely an illegal S trap.

Thanks... I was afraid of that. If not a pedestal, then how high does the drain get come out of wall?

Hi Bob...

Waste for average bathroom sink comes out at 18" to center off the finished floor...

If AAVs (automatic air vent) allowed in your area, you may install one of those in place of a roof vent. Good luck, Tom