I'm planning to remove a bathtub and replace it with a shower. I'm planning to create the shower base myself, rather than buy a pre-made pan. However, I won't be able to move the drain, since I'm on a slab. So the new shower base will be the same dimensions as the tub, with the drain in the same location. Is there any problem with setting up the shower this way? If I put the shower drain on the end rather than in the middle, will it lead to any issues that I'm not expecting?

  • Concrete is not immutable - you can move the drain if you want to, and apply a hammer and masonry chisel (diamond saw optional.)
    – Ecnerwal
    Jan 27, 2018 at 1:46
  • Yes, but I own a unit (condo) in an apartment building. I haven't actually confirmed that I'm not allowed to move the plumbing in the slab, but if I can help it I'd rather not.
    – Joel M.
    Jan 27, 2018 at 2:00

2 Answers 2


As long as you have sufficient slope to the drain you are okay. Typically 1/4" per foot.

  • 1
    I agree as long as there is a slope it will be fine , center drain all draining to the center, or a leniar drain along 1 wall both work, I have done both on different homes with good results.
    – Ed Beal
    Jan 27, 2018 at 1:44
  • 2
    Schluter even makes two tub-to-shower foam bases, one for center drain, and one for the tub's original drain location. (This would be for a kerdi membrane tiled shower, but illustrates the point of drain location)
    – Tim B
    Jan 27, 2018 at 1:47
  • 1
    +1 on the Schluter foam pans. They are fast and easy to install and much easier to really waterproof well with their kedri membrane than traditional dry-packed mortar and redguard. They are also easy to customize if they don't quite fit the actual installation dimensions quite right.
    – C Knight
    Jan 27, 2018 at 2:32

the only thing stopping you is wether or not it is a 2 inch drain. almost ever 1 tub to shower convertion ive done has been 1 1/2 inch drains. shower need that 2in. drain to be effective. with 1 1/2 in. the water could fill the base. other then that, drain placement make no difference for a custom pan. 1/4in. per foot off the longest run, transfer that line around the rest of the base. and if your doing a 3 piece shower drain please remember the preslope.

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