Where the heck is the P-trap? (Tub drain in slab, with pics)

Discussion in 'Remodel Forum & Blog' started by joshuagmh, Apr 15, 2019 at 8:26 PM.

  1. joshuagmh

    joshuagmh New Member

    Missouri City, TX
    Hey guys. New member here. In the middle of my home bathroom remodel. I have a background in construction, but I will admit I am very limited on plumbing experience.
    The house is on a slab, in Texas (Houston area).
    I had and existing tub, and am adding a new one. I knew from the beginning that getting the new tub drain to align properly would be my biggest concern/fear.
    So today I started chipping away at the concrete around the old drain, expecting to find the p-trap pretty quickly. I need to extend the drain about 2 feet from where it currently is. But as I started chipping away, the first bend that I thought was the beginning of the trap just bends 90 and goes straight down.
    I was going to add the trap directly beneath the overflow drain on the new tub, and was just trying to dig the old one out tonight to get an idea of the slope and angles I will need. But I cant find the dang thing.
    Could it really be buried even deeper under the slab? I've hit dirt!
    I attached some pics for reference.
    The first is the original tub still in place, with its drain pipes in tact.
    The second is the hole after chipping away the concrete. You can see the pipe dive down. No trap (yet).
    The third is a view looking toward the wall where the vent pipe is. The green tape on the wall marks where the vent goes up. So I assume the vent pipe connects (generally) directly to the drain in this direction. (There is also a shower, directly behind me from the perspective of this pic)
    The last one is a pic of the general slab layout/rough-ins that they do in this area, just as a reference. I know slab construction can vary heavily depending on what part of the country you live in (this is another house in my neighborhood currently being built).

    So, what am I missing here? Is there a trap? Is it possible there isnt one? how deep or far away could it possibly be?
    Previous tub drained fine, and had no issues.

    IMG_8707.jpg IMG_9344.jpg IMG_9346.jpg IMG_9282.jpg
  2. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona
    The trap is at the bottom of the riser pipe. DO NOT put another trap under the new tub.
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  4. joshuagmh

    joshuagmh New Member

    Missouri City, TX
    Thanks for the reply!

    So I can extend that drain about 20" without problem, and rely on the existing p-trap under the riser?
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