I removed a large light structure from my 1990s kitchen ceiling in order to install canless led lights and learned the p-trap from the shower in the floor above rests 5" below the joists preventing me from installing drywall flush with the joists. I am wondering what my options are for reconfiguring the p-trap.

The joists are 9.5" in height. The bottom of the p-trap sits 5" below the bottom of the joist. The shower drain pipe connects to the air vent and then main waste pipe. The distance from the center of the p-trap to the connection to the air vent is 17".

I mocked up a potential solution on paper shown here though don't know if that would constitute an s-trap or other code violation. enter image description here enter image description here enter image description here enter image description here Link for short video of area

Thank you for any input you could share.

  • About the only way would be with a couple of flexible rubber repair connectors to bend the pipe up enough. Those pipes/connections are hard plastic and should be in a straight line when gluing together.
    – crip659
    Jan 3, 2023 at 22:25
  • I'm no plumbing expert, but I would think that your proposed solution would work. You'll have a steep drop after the trap goes back up, but this is a shower, so you shouldn't have to worry about keeping too many solids floating down the drain line. It might make snaking the drain very difficult, though, so you'll want to be sure to keep up maintenance on a regular basis so you don't have to get a big snake down there.
    – FreeMan
    Jan 4, 2023 at 12:29

1 Answer 1


What you have shown in your proposed sketch would be an s-trap and most likely a code violation.

The trap can be raised approximately the distance between the top of the p-trap to the underside of the subfloor (see X below). enter image description here

It can be raised by reconfiguring the piping, as shown below: enter image description here

This assumes that the vent is a dry vent and not a wet vent (nothing is draining into the vent from above). This also assumes sufficient distance downstream of the vent to allow for the vertical offset.

To obtain maximum height, you might have to bury the hub of the sanitary tee up into the floor/bottom plate of the wall above, and if so, you might have to open the wall above to make the connection.

  • Thank you so much for your informative response! I will give this a shot. Yes it's a dry vent. Would you have any suggestions for how I could ensure there's "sufficient distance downstream of the vent to allow for the vertical offset?"
    – Dan M
    Jan 4, 2023 at 2:13
  • Your best bet is to lay the fittings out on the floor and take a measurement (you can do this in the store or buy them and take them home and return them if it doesn't work)
    – pdd
    Jan 4, 2023 at 17:30

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