Alternative method for connecting sink drain with waste pipe directly under?

Question

This seemed so much easier in my head before I started.

The sink drain is just about directly over the waste pipe. I glued this together with two 45s and a 2 to 1 1/2 wye. I need to connect an AAV to the top of the wye. The P trap doesn’t line up perfectly with the top 45. I’m not happy with it, it’s forced. The P trap does not screw together easily. I have access to the basement it’s open. I was thinking about cutting off the bottom 45 and starting over. Any suggestions on how I can do this the right way?

Answer 1

Since this is NOT buried in concrete, don't use a glue-together trap at all.

Problem the first (apart from what you mention) is that the vent is too close to the trap - it needs to be at least 2 pipe diameters away from the trap or it's a "crown vent" and (even more) prone to clogging. One plunger event later and your AAV is full of sink clog crud. Problem the second is that 45 degree pipes are OK in vents, bad in drains - drains should either be vertical or "horizontal" (at proper slope, 1/4" per foot in this size) because excessive slope tends to have the liquid run away leaving solids behind, and those solids build up in the pipe until it clogs.

Buy a polypropylene slip-fit trap (which has the same exit the sink tailpiece does, and the entrance compression fitting for the sink tailpiece built in.)

The elbow in the lower left should be a "long-radius bend" not a sharp elbow - takes too much time to draw nicely

Put a cleanout in the elbow (so, use a sanitary tee with a cleanout plug, not an elbow) where the drain comes through the floor, and then (maintaining proper 1/4" per foot slope) go sideways far enough that when you come up, the AAV can be well away from the trap exit (minimum 2 pipe diameters) and make sure to extend upwards from that tee so the AAV is also as high as possible (but still able to be unscrewed and replaced) in the cabinet, if you don't run it even further up inside the wall cavity to an access panel (so it can be replaced when needed, but "when needed" may be less often.)

Alternatively, move the pipe in the basement and drill a new hole that's not poorly placed right under the sink

From there, extend the pipe back towards the trap (maintaining proper 1/4" per foot slope) and install the trap adapter on the end of the pipe. The combination of the slip-fit on the tailpiece and the slip fit entering the drain (plus the union joint in the middle of the trap) provides considerable adjustability to get things right, as opposed to a "glue and pray and then swear" approach that a glue-in trap requires. Note that slip fit ends (on the tailpiece and trap exit) can be trimmed to fit if they are too long, but you should not overdo that (they have a couple of inches of adjustable range.)

Answer 2

Ended up moving the waste pipe in the basement for a cleaner look. Let me know what you guys think.

Answer 3

Here is a suggestion

You would need 3 x 90° outlet elbow with captured nuts

I would not glue but use Threaded for IPS