Building New Shower Pans

Discussion in 'Shower & bathtub Forum & Blog' started by Designie, Sep 8, 2010.

  1. Designie

    Designie New Member

    Messages:
    39
    Location:
    Detroit, MI
    Well, I'm sure there is a thread somewhere on here, but in case there's not....

    I'm building a new home and I have 2 fully tiled shower surrounds in 2 of the bathrooms. The first thing I noticed is that when i rough plumbed the drain, the book I had said to cut a 7" hole. Now, I have a hole that is bigger than the standard 3 piece drain from Sioux Chief that I got at HD. What is gonna hold up the mud when I try to build my first mortar bed? I'm already confused....

    Anyway, if anyone has a good step by step for building a good, solid pan, please let me know.

    Thanks.
  2. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    Your best bet is to check out johnbridge.com

    Start with the "Liberry" (couple good threads about deck mud and building showers): http://www.johnbridge.com/vbulletin/forumdisplay.php?f=8

    They are also very helpful over there, so if you have additional questions, just post them up and I'm sure you'll get some excellent help.

    Before you build the shower, you may want to look into Kerdi or other surface applied membranes. They have several advantages over a traditional shower. If you do build a traditional shower, do lots of reading and take your time. A traditional shower can work great if it is done correctly, but there are several spots where people typically make mistakes when constructing a traditional shower pan.

    Good luck!
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,691
    Location:
    Cave Creek, Arizona
    1. You read the WRONG book.
    2. You also may have the wrong drain if it is much smaller than your opening.
    3. What is supporting the drain fitting, if you do not have any subfloor under it?
    4. At this stage, you just pour the mortar up to the edge of the opening.
  4. Designie

    Designie New Member

    Messages:
    39
    Location:
    Detroit, MI
    Yeah, I believe I mis-read the part about cutting the hole for the drain, I'm pretty sure that was for a pre fab shower pan, not a built up pan.

    That Kerdi stuff looks pretty impressive. Do you mean to tell me that you can tile right over it once it's set? And you can use drywall on the walls instead of concrete board??

    I may have to re-consider how I am going to build these. I really like this Kerdi system.
  5. nukeman

    nukeman Nuclear Engineer

    Messages:
    711
    Location:
    VA
    That is correct. You do need the Kerdi drain instead of the one you have, though. Basically do this:

    - set Kerdi drain
    - build mud pan (cheap/easy)
    - regular drywall on the walls
    - cover all surfaces (to shower head or above) with Kerdi, 2" minimum overlap at seams. Consider Kerdiban in the corner seams to minimize build-up
    - cover with tile

    If you build a regular shower, it is a little cheaper, but there is more work. The Kerdi is also totally waterproof and dries out faster, so less mold/mildew problems on the title. A regular show also requires to build a pre-slope part of the pan, properly install the liner (easier said than done), then build the top part of the pan. The drywall that can be used in the Kerdi shower is also cheaper and easier to work with than the CBU used in a traditional shower.

    There is lots of info on Kerdi on the johnbridge site. They also have a great e-book on the tricks for making the install easier/better on that site for $10.

    Some people will build the walls and Kerdi/tile them before even making the pan. The advantage of this is that the thinset tends to fall off the walls and make a mess. If you do the floor last, then you don't have to worry about cleaning the thinset off your finished tile floor.

    I would strongly consider Kerdi. If you run into any questions/problems on the install, just start a thread on johnbridge and the guys over there will help out with whatever you need.
  6. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    I've used Kerdi several times, and it works well. I think they have a conversion drain that you might use on your existing one, but it still does need to be supported. You might end up cutting a section of subflooring out and replacing it to get the needed support with either a conventional or a Kerdi shower. If you are leary about building a mud pan (it's not really that hard), they do make foam panels that are sloped...you can just cover with Kerdi and tile. You don't need to wait for the Kerdi thinset to cure before you start installing tile. And yes, drywall is the preferred medium for walls on a conventional shower. They do recommend cbu IF you are building a commercial steam shower, but then those things see far more moisture than any home unit ever would.
  7. Designie

    Designie New Member

    Messages:
    39
    Location:
    Detroit, MI
    I am replacing the section of subfloor around the drain so that I can cut proper size holes and give the drain flange support. Then I can build the mud pan. I have no worries about building the pan, I'm pretty comfortable with mortar, cement and such.

    Using drywall is definitely a cost and ease of installation advantage. The reason I can think of to use Durorock is that it would make a more rigid wall for the tile to be set on.
  8. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    Assuming you have normal stud spacing, normal drywall with the membrane then tile is plenty stiff enough. The Kerdi membrane acts like a reinforcement layer, and then you have the tile grouted together and it is plenty stiff. BTW, the paper grain on drywall makes it stiffer when installed horizontally, not vertically. If you want more stiffness, you could use 5/8" stuff...it would depend on the trim of the edges of the tiled shower whether that would be a pain or not, but it is not needed.
  9. johnfrwhipple

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

    Messages:
    4,234
    Location:
    North Vancouver, BC
    Post(s) removed by John Whipple
    Last edited: Mar 18, 2014
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,691
    Location:
    Cave Creek, Arizona
    fasten a piece of plywood UNDER the subfloor with the smaller hole in it, and then set your shower drain on it. That should position it at the proper level.
  11. RenePF

    RenePF New Member

    Messages:
    6
    Location:
    Chicago IL
    I just put in a TileRedi prefab tileable pan. Like Kerdi. Expensive ($600), but no worries about leaking into the condo below me. The hole in the floor doesn't need to be that precise, as the pan covers a variety of sins.
  12. Wedi is a product I haven't heard much about recently. I've used it. Very impressive. Way easier and faster than Kerdi.
  13. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,059
    Location:
    New England
    Kerdiboard would end up similar, except you'd still need to put the membrane on the pan. Wedi offers more kit options for pan sizes, and pieces to extend the size from one of the 'stock' sizes. they also have some really interestingly shaped kits, like a doorless scrolled design that would be hard to replicate any other way. With Wedi, you need to use their glue/adhesive on the penetrations and seams, then mesh tape and cover them, similar to using Kerdi-band on the seams of Kerdi or kerdiboard, except you are using thinset rather than the more expensive adhesive. The biggest part of any of those kits is the pan, and Kerdi works just as well if you choose to form yours out of deckmud verses their foam one, so that gives you a little more flexibility and the possibility of cost savings.

    When you compare cbu, tape, screws, verses drywall and Kerdi membrane, the cost differential goes down on a conventional construction shower. Then liner, corners, clamping drain verses the flexibility of the Kerdi drain, and the pan isn't too bad. The Kerdi drain is one of the more expensive parts, though. The flexibility and square cover are nice. It's the only one I know of where you have about 1-2" of flexibility of the drain location to optimize where the tile joints go regardless of the exact location of the actual drain pipe.
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