Installing rain shower head with 20" shower arm

Discussion in 'Shower & bathtub Forum & Blog' started by AlSr1, Nov 8, 2012.

  1. AlSr1

    AlSr1 New Member

    Messages:
    1
    Location:
    Renton, WA
    We have a new home under construction and we are considering putting a 20" long horizontal shower arm for a 10" rain shower head. Our general contractor feels that such a long shower arm is not feasible. I am exploring whether we could make this work.

    I assume that there will be a drop ear elbow, a nipple, shower arm, and the shower head (connected in that order). Please assume standard part dimensions for drop ear elbow and nipple.
    a) Is there a convenient way to attach the drop ear elbow more rigidly to the 2x6 cross brace? Would it be helpful to further clamp the drop ears with small metal bars to the cross brace?
    b) Would the threaded joints between the drop ear elbow and the nipple be strong enough? Is there a way to provide additional support to the nipple - by a bracket perhaps?
    c) Will the threaded joint between the nipple and the shower arm be strong enough? Are there brackets used to provide additional support to shower arms?

    Thank you in advance for your attention and I would really appreciate your comments.
  2. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    When you say "shower arm" I am thinking an arm extending from the WALL. That is not a good way to mount a rain head....20" is way too long for that. Piping inside the ceiling to a drop ear elbow secured to a brace is the way to go,
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    Your problem will NOT be with the drop ear elbow. If you have a problem it will be with the 20" arm snapping its thread where it is screwed INTO the drop ear elbow.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    You really want the thing coming from the ceiling, hanging down, not cantelevered off of a long arm unless you can find one with a support near the end to keep it from flopping around...that's a long lever, and often the rain heads aren't all that light.
  5. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,944
    Location:
    North Vancouver, BC
    20" arm is not that long. It really depends on the quality of the fittings.

    Many parts these days are Chrome Plated Plastic. Not so good. You seen them in many suppliers parts. Better parts are Chrome Plated Brass which many of the higher end suppliers use.

    When fitting a large shower arm it is important to remember the weight of the shower head and you might need to angle the "Wing Back" (part that the shower arm threads into) a little up so when the shower arm and shower head are installed the arm sits level.

    You should also check that the arm comes out at 90 degrees to the tiled wall.

    [​IMG]

    Here is a shot of my plumber fine tuning this for our client. If the shower arm is adjusted a little out of level to compensate for the weight of the shower arm it is important to let the tile setter know so he does not change this when the grouting is placed.

    JW
    Last edited: Nov 10, 2012
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    shower arms are not made with the highest grade, or heaviest, brass pipe, so they WILL crack at the attachment thread under stress. IF the weight of the shower head flexs the arm to the extent that you have to compensate for it, then you DO have a lightweight arm, even if it is brass.
  7. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,944
    Location:
    North Vancouver, BC
    Thanks HJ

    I think the real key step here is having the pieces onsite so the plumber can dry fit and check both that the arm sits level and square to the wall.

    JW
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    I would NOT install a big rain head with the shower arm 20" long unless it was coming out of the ceiling and thus vertical (but that would require quite tall ceilings to be of practical use). The risk is just too great of cracking the arm in the wall. Your results may differ...I'm somewhat risk adverse. If you did, you'd want to make sure the fitting was well anchored to a solid piece of blocking and the arm itself was the highest thickness/grade you can find.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,488
    Location:
    Cave Creek, Arizona
    I replaced a short shower arm yesterday, (not the first one ever, however), which snapped off at the drop ear elbow, and if it can happen to a short one with a medium sized head, I would never trust a long arm with a big head;.
  10. johnfrwhipple

    johnfrwhipple I love these ACO Shower Drains - Best in Class

    Messages:
    3,944
    Location:
    North Vancouver, BC
    Yet another reason I love the Dornbracht fixtures. The design of the Dornbracht system allows for worst case scenerios like this to leak out the face of the trim not the back side of the shower wall.

    JW
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