bathtub to shower conversion

Discussion in 'Shower & bathtub Forum & Blog' started by slapappy, Jan 20, 2011.

  1. slapappy

    slapappy New Member

    Messages:
    5
    Location:
    Chicago
    Hi all, I'm new to the forum, and had a question about shower drains. My customer has chosen to replace his tub, and install a fiberglass shower receptor. The tub had a 1 1/2" trap and trap arm, which ties into the 2" drain line. I know that a shower is supposed to have a 2" drain, but it's simply not an option. Even if I could get access, which would involve wrecking the ceiling of the recently remodeled powder room below, there isn't any way to tap into the drain line. The bathroom is on the second floor, with another bathroom behind it, and a laundry room is on the side wall. There are drain and vent pipe connections for 2 tubs, 2 lavatories, and the laundry standpipe. The tees off of the drain pipe are spaced so close together, that even is I could cut out the 2 x 2 x 1 1/2 tee, there wouldn't be enough pipe next to the adjacent tees to solder on a new one. I know they are not going to want me to trash the powder room below, and the wet wall in the newly remodeled kitchen to cut out everything and start over. I have informed them of the possible risks involved with using 1 1/2" drain pipe for a shower, and that it was against code. They are willing to accept the risk, and so am I. I live in a 110 year old house, with 1 1/2" cast iron drain in my shower, and never had any problem. My question is, what to do about the shower drain. Every drain I've seen with a 4 1/4" flange is designed to be connected to 2" PVC, and I need to connect to 1 1/2" copper. I've been a remodeling contractor for 25 years, so I'm not some naive homeowner who doesn't know what they're doing. I've simply never run into this situation before. Please, no condescending remarks, or lectures on needing to trash their house in order to "do it right". I'm all for doing it right when at all possible, and usually go beyond code to know that what I've built will still be there in 100 years, but I know that my customer isn't going to spend 30 grand to remodel a 5 x 7 bathroom!! Any ideas regarding the shower drain?
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,947
    Location:
    New England
    First, if this is being inspected (and legally, it should be), see if the inspector will give you a variance. If not, walk away, as your license is up for grabs...
  3. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    If your looking for someone to say to use the 1-1/2" drain you won't find him here. You also say you have a 1-1/2" cast iron drain in your shower. There is no such thing as 1- 1/2" cast iron.

    John
    Last edited: Jan 20, 2011
  4. slapappy

    slapappy New Member

    Messages:
    5
    Location:
    Chicago
    I meant 1 1/2" steel drain pipe, and I was talking about my house, not my clients'. What exactly is your point? To feel superior? To belittle me? Any constructive advice?
  5. The Canadian code never got around to increasing from 1.5" to 2", and showers drain just as well in Canada as in your house. Hint hint. I think the increase to 2" size was good for builders; it allowed them to build bigger houses without worrying about venting as much.
  6. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,049
    Location:
    North Vancouver, BC
    Post(s) deleted by John Whipple
    Last edited: Mar 18, 2014
  7. slapappy

    slapappy New Member

    Messages:
    5
    Location:
    Chicago
    Thanks for the reply, John. Any idea where I might find a drain designed for a fiberglass shower receptor? The flange would need to be 4 1/4". Also, just curious, why cast iron? Wouldn't it be better to use a brass trap when tying into copper?
  8. Try Oatey.

    There are two concepts mixed together here.

    One is whether to use brass or another material. That is UNimportant for now. Later, you can figure out which material to use and why.

    As JohnFR pointed out
    "Many 2" drains ... 1 1/2" in the outlet hole anyway."
    Do you know if the Schluter drain have a 2" hole in it or a 1.5" hole? Go look.
    Getting comfortable with 1.5" is easy.
    Talking to authorities about it might not be the happiest moment.

    A 1.5" drain carries water a certain distance.
    A pipe smaller or larger carries water a different distance.
    Hint hint.
    It's all a matter of the length of the pipe. Developed length.

    Any pipe self-vents well up to a certain distances, depending on the length and its slope. Don't overslope it; that will reduce its carrying capacity. A pipe carries air backwards while it carries draining water forwards, so it needs a gentle slope. Stay at 1/4" per foot if you want to be sure you know (and everyone else knows too) its carrying capacity.

    In your next post, you owe me a word thanking me.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,947
    Location:
    New England
    The Kerdi drain has a standard 2" pvc or abs socket on the bottom, and that is the smallest opening in the thing. http://www.schluter.com/media/ShowerHandbook.pdf They do also have conversions from a standard clamping drain and commercial metal (ss) versions, if required, for your application. The (stated) reason the US went to a 2" drain for showers (where 1-1/2" is still okay for a tub) is that if the drain was momentarily blocked (say standing on it or dropping a washcloth, etc.) is that the 2" drain would allow the accumulated water to drain fast enough to not overflow the (usually) short curb once you realized it. A tub has an overflow drain, a shower does not - if it overflows, it goes out on the floor. Few like standing in water while taking a shower, and the larger drain helps to prevent that. All things being equal, a 1-1/2" drain should work, but the codes are written for the 'what-if' situations.
  10. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,049
    Location:
    North Vancouver, BC
    Post(s) deleted by John Whipple
    Last edited: Mar 18, 2014
  11. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    4,049
    Location:
    North Vancouver, BC
    Post(s) deleted by John Whipple
    Last edited: Mar 18, 2014
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