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Community and Q&A

Basement cement floor as shower pan

blueskye | Posted in Green Building Techniques on

Our planned basement shower pan is a 5′ x 5′ area of the poured concrete floor, sloped on all four sides to a central drain and sealed.

This isn’t a normal request for a concrete contractor, I’m sure. Has anybody our there done it this way? Are we setting ourselves up for trouble?

(By the way, Plan B is to have the contractor drop the floor a couple of inches in this area and have the tile guy build a conventional mortar bed, Kerdi waterproofing and tile shower pan.)

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  1. Expert Member
    Michael Maines | | #1

    Esther, in theory your approach could work, if the concrete sealer never fails and if you can get the drain assembly to work in a cast-in-place installation. In reality, it is highly likely that the sealer will eventually fail and you will be saturating the concrete, leading to various problems.

    You will be much better off recessing the concrete as a "mud pan," using Kerdi (or another waterproof membrane) on top of the pre-sloped concrete, using a standard drain assembly, and finishing the shower floor with tiles. There are porcelain tiles that are made to look like concrete.

    If you really want the monolithic concrete look, instead of tiles you could use a special concrete mix with small aggregate, allowed to set up very slowly for maximum strength, over the waterproofing membrane. The concrete would need to be sealed and maintained. You would want to find someone skilled in concrete countertops and other specialty work, not your average tiler or concrete guy.

  2. blueskye | | #2

    Michael - thanks so much for your detailed response! I appreciate the options you laid out.

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