Converting tub/shower to just a shower

Discussion in 'Shower & Bathtub Forum & Blog' started by Home Girl, Nov 11, 2009.

  1. Home Girl

    Home Girl New Member

    Messages:
    3
    Location:
    Vacaville, CA
    I have a large soaker tub from the 70's with wide sides and a deep tub. I need to convert this to a standard shower for handicap access (the current tub presents a safety concern with getting in and out of it). The house foundation is concrete slab and I have already located a supplier for a shower pan that can use the existing drain location for the new shower. What is the simplest way of dealing with connection/drain issues? Can I leave the existing tub drain/vent in place and work with what is there? I am a single woman on a limited income and want to do the work myself if at all possible.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,269
    Location:
    New England
    Your first problem is the probable size of the drain...a tub is generally plumbed with 1.5" line, and a shower requires a 2" drain. Now, since it is in the slab, and some locales have a minimum size required for below slab, it may transition to 2". But, you'd have to crack some concrete. once you've done that, you could put the drain anywhere you want and not be limited to a specific shower pan. Depending on the labor rates, and the cost of the pan, it may be about even to have a tiled shower base installed, then that could be any size or shape you wish with the drain where you prefer it.

    The reason a shower is required to have a larger drain than a tub is a tub has a lot more capacity to hold water if for some reason the drain gets blocked before overflowing - plus, the tub has an overflow drain connection that a shower doesn't. Drop the wash cloth, cover the drain, and if not careful, it could be running over the curb. Not likely to happen in a tub.

    A good resource for tiling help is www.johnbridge.com. Even if it is just to understand if your contractor is building it right, it's a good resource for knowledge and understanding.
  3. Gary Swart

    Gary Swart In the Trades

    Messages:
    7,387
    Location:
    Yakima WA
    You will definitely have to go with the 2" drain since this will not have a raised curb to create a holding reservoir like a regular shower. The few that I have seen have just a gentle slope into the actual shower area. That's enough as long as the drain stays open, but a clogged drain could be a serious problem!
  4. You can use the existing drain. You can keep it the same size. You do not need to increase the size of the drain. To be good, tell the next buyer of the house tht the drain is only 1.5" diameter. It's not a big deal.

    Having said that, I or others may still need to respond to future posts from people who would have you replace the entire drain pipe under the concrete slab. Stay tuned for more learning.
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,269
    Location:
    New England
    Your building inspector might give you a variance on the size of the drain, but, at least in the USA, the code says it must be 2". Yes, it is likely to work, but you'd need an adapter for the pan, since 99% of the shower drains are 2" to comply with the code. It's never a good idea to neck down a drain, so you'd have to try to find a 1.5" drain, which won't be easy - plus, nearly all pans are made to fit a 2" one.

    So, good luck...
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,056
    Location:
    Cave Creek, Arizona
    shower

    IF you get one of the "retro" shower bases with the drain at the end, which were made to utilize the existing tub drain location, it may be set up for a 1 1/2" pipe. If not, then you will not know what size drain you have until you break out the concrete.I can appreciate you wanting to do it yourself, but a bad shower drain installation will NEVER go away.
  7. Inspektor Ludwig

    Inspektor Ludwig Journeyman/Inspector

    Messages:
    167
    Location:
    In the good ol' UPC
    I agree with the other posts that say
    you need to have to 2" tailpiece, trap and trap arm. I believe CA. uses the UPC for plumbing code and it clearly states that you need to increase to 2". The tub should have 1 1/2 all the way to the vent, which should be right next to the existing location of the tub drain. When you remove the tub, there should (hopefully)be a boxed out portion of the slab where concrete was not poured. This made installing the tub and tub drain easier. Follow the tub drain to the wall. At that point there should be vertical pipe going up (vent) and one going down (drain). If that drain pipe going down is 2" then that makes it easier to change the trap, if it's 1 1/2, then you would need to follow that drain pipe down until you find where it goes horizontal. At that point it should turn to 2". It may seem like a lot of work but there's a reason why you need a 2" drain for shower. The amount of water is not a "set" amount like filling a bathtub. Your shower pan can easily overflow if you have hair in the drain or a bar of soap blocking the drain etc. Do it right the first time then you don't have to worry about it later!;)
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,056
    Location:
    Cave Creek, Arizona
    drain

    quote; if it's 1 1/2, then you would need to follow that drain pipe down until you find where it goes horizontal. At that point it should turn to 2".

    If the drain is 1 1/2" to the tee, and usually even to the trap, then the ENTIRE line from the connection at the main line will be 1 1/2". Changing that connection to 2" will usually be well beyond the abilities of a DIY'er.
  9. daren

    daren New Member

    Messages:
    4
    Location:
    Buffalo,NY
    I plan on doing this soon and I haven't fully research this yet but wouldn't be cutting out old connection and attahing new with a "Fenco?" fitting?

    DRB
Similar Threads: Converting tub/shower
Forum Title Date
Shower & Bathtub Forum & Blog Converting old 2-faucet to single faucet on tub/shower Feb 17, 2005
Shower & Bathtub Forum & Blog Converting a tub/shower to shower only Nov 28, 2004
Shower & Bathtub Forum & Blog Basement tile shower (drain) install - converting existing floor drain Mar 13, 2014
Shower & Bathtub Forum & Blog Converting an old Adobe Wall into a new tiled shower wall - How to plan step by step Jun 4, 2013
Shower & Bathtub Forum & Blog Converting from tub to shower - Drain questions Mar 9, 2012

Share This Page