Shower to bathtub conversion - drain question

Discussion in 'Shower & Bathtub Forum & Blog' started by Jon Lehman, Jul 23, 2012.

  1. Jon Lehman

    Jon Lehman New Member

    Messages:
    4
    Location:
    California
    I am converting a shower to a bathtub, and need to move the drain. As you can see in the pictures, I have already removed the shower, and ripped out some of the concrete slab. Instead of digging up more concrete (which seems to be in two layers, is quite thick, is reinforced, and is difficult to remove with a sledgehammer), I would like to:

    1) cut the existing pipe so that I can
    2) install a 90 degree elbow in it and
    3) use a 1.5 inch pipe to reach the tub drain, approximately 1.5 feet from the elbow.
    4) install a p-trap
    5) insert a 12" plastic box
    6) pour concrete
    ...

    Is the 90 degree elbow ok?

    Also - in order to access the tub to connect everything up, I am going to have to cut a hole in the wall. This is an exterior wall in the back of the house. I'd like to install an access panel to cover up the hole - so that I can get to it later if I need to. What do I need to keep in mind regarding this access panel?



    Note the vent behind the toilet that is barely visible in one of the pictures.

    Also, the shower was 60". I've measured the space, and it is about 60 1/4" wide, so a tub should fit there fine.

    Wide Angle - Bathroom.jpg over drain - Bathroom.jpg
    Last edited: Jul 23, 2012
  2. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,406
    Location:
    North Vancouver, BC
    There is a lot that needs to be done here.

    1). That poly under the slab needs to be mended at the end.

    2). I would keep everything in 2" and change to 1 1/2" just before the T where the drain and overflow connect.

    3). 90's are not allowed unless they drop into a vertical line

    4). I think the make bends can not exceed 135 degrees.

    5). You need to break up more concrete against the back wall most likely. Get your tub in rough position with the drain and overflow dry fit.

    Good Luck.

    JW
  3. Jon Lehman

    Jon Lehman New Member

    Messages:
    4
    Location:
    California
    Thanks for your reply...much appreciated

    So would this be ok?



    over drain - Bathroom - with 45.jpg
  4. Terry

    Terry Administrator Staff Member

    Messages:
    15,123
    Location:
    Bothell, Washington
    You can use a 90 on the trap arm horizontally.

    The tub waste and overflow set right up against the 2x4 stud wall. More concrete will need to come out there.
    What you have drawn there is for the drain in the tub, the p-trap will be against the wall, allowing the overflow to mate up at the overflow position.
  5. Jon Lehman

    Jon Lehman New Member

    Messages:
    4
    Location:
    California
    Here's what I understood you to say...is this right?

    over drain - Bathroom - with 90 and p-trap.jpg
    Last edited: Jul 24, 2012
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,123
    Location:
    Bothell, Washington
    That should work.
  7. Jon Lehman

    Jon Lehman New Member

    Messages:
    4
    Location:
    California
    perfect, thanks!
  8. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,406
    Location:
    North Vancouver, BC
    Terry would it be safer to use a double 45?

    I did not think a 90 was allowed on a horizontal run.

    JW
  9. Terry

    Terry Administrator Staff Member

    Messages:
    15,123
    Location:
    Bothell, Washington
    You can change direction horizontally if you are using waste fittings. Two 45's are the same as one long turn 90.
  10. johnfrwhipple

    johnfrwhipple Bathroom Design & Build - North Vancouver, B.C.

    Messages:
    4,406
    Location:
    North Vancouver, BC
    So one long 90 is OK and a short 90 would be a no go?

    Does the use of the 90 have any affect in flow rates? I have measured slower drain rates when above the P Trap the waste water travels down and out at a 45 degree angle vs straight down. We have be recording flow rates and trying to come up with a rough formula here in Vancouver but because of the fact every shower is different none of the data makes any sense yet. Maybe in another decade a formula will emerge.... lol
  11. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,825
    Location:
    Cave Creek, Arizona
    quote; What do I need to keep in mind regarding this access panel?

    The biggest things are that it is NOT needed and it will probably never be used if you do install it. I have installed hundreds, if not thousands of tubs and have never had to make an access hole if there was not one there already, (if there was one there already it was a convenience, not a necessity). Once the tub is installed, and installed properly, EVERYTHING you have to do to it can be done from inside the room. Use a long radius 90 and you will be fine.
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