Plumbing – do if drain alignment doesn’t allow enough space for p-trap

bathroomdrain-waste-ventplumbingsink

I'm remodeling my bathroom. The sink drainage come up from the floor. The alignment between that and the drain coming from the sink doesn't have enough space for a p-trap to be installed so it just falls into place and connects the two (prior to remodel there was no p-trap).

I was thinking having a 45 degree pipe come out of the sink, forward then down, then attach the p-trap, and that would allow enough space for overflow to go back and down to floor drain pipe. My crude image of what I mean, circled in red.PTrapImage

Would this allow for proper drainage?

Best Answer

When you purchase a P-trap from the hardware store, you'll end up with these pieces (or something similar).

P-Trap pieces

You'll also want to pick up a 1-1/2 in. PVC 90° slip-joint elbow while you're there.

1-1/2 in. PVC 90° slip-joint elbow

You'll then want to connect the pieces something like this...

Connect these pieces

You'll then have to twist the pieces around, until you can get them to fit together. You'll end up with something similar to this.

twisted p-traptwisted p-trap

Though I'm not sure this is code compliant anymore.

In the 2003 version of International Residential Code (IRC), there was this section.

International Residential Code 2003

Chapter 31 Vents

Section P3105 Fixture Vents

P3105.3 Vertical leg for waste fixture drains. A vertical leg (see Figure P3105.3) is permitted within a fixture drain of a waste fixture in accordance with the following criteria:

  1. Minimum trap diameter shall be in accordance with Table P3201.7.
  2. The diameter of Section A shall be equal to the diameter of the trap.
  3. The length of Section A shall not be less than 8 inches (203 mm) and in accordance with Table P3105.1.
  4. The diameter of Section B shall be one pipe size larger than the diameter of Section A.
  5. The length of Section B shall not be more than 36 inches (914 mm).
  6. The diameter of Section C shall be one pipe size larger than the diameter of Section B.
  7. The total length of Section A and Section C shall not exceed the distance allowed in Table P3105.1.
  8. Bends shall be the diameter of the largest connected section.

FIGURE P3105.3 VERTICAL LEG FIXTURE DRAIN SCHEMATIC

However, in the 2006 version, this section is gone.

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