I have a two year old tiled shower with glass enclosure. The grout is sanded grout. The exterior corner of the shower curb is leaking a small bit of water after every shower. Over time it has corroded the paint and molding that butts up to the tiled curb.

The leak is through the grout. No water exits on top of the curb.

The shower enclosure is caulked with 100% silicone in the places specified by the installation instructions. The only weird thing to me is that the bottom channel sits directly on a grout line. I'm wondering if water is seeping into the grout and working its way outside.

Any ideas what could be wrong? Pictures show leak location on exterior of curb and the opposite interior side of the shower curb.

exterior of curb where leak is

interior of curb

  • It looks like you have a problem with seepage behind the tile (since a leaking shower should not soak into the wall so much).. My assumption is that water is seeping in from the interior of the shower and running behind your wall tile... Questions: how high do your wall tiles go, do you have wall tiles inside the shower, if you tap the wall tile in the picture, does it sound hollow?
    – Hightower
    Nov 25, 2013 at 14:06
  • The whole shower is tiled almost to the ceiling. During construction I saw that the builder used green wallboard on the walls and some kind of cement looking board up to curb level in the pan. Behind the drywall and base molding that are deteriorating, there are 2x4 studs.
    – Stress
    Nov 25, 2013 at 14:51
  • 1
    They should have used cement board behind all of the tile. Google "green wallboard" and read about it. It's not made for putting behind tile. It sounds like you have an issue with the contractor.
    – getterdun
    Nov 25, 2013 at 16:37
  • Sorry, getterdun, I misspoke. The "green" wallboard was on other walls in the bathroom. The tiled shower had gray cement like walls. I'm not an expert or in the builder trade, so I don't know if it was all done correctly, of course.
    – Stress
    Nov 25, 2013 at 20:58
  • Are there any "features" on that wall in the shower? That looks almost exactly like what happened to my shower because the waterproofing on the shower seat was installed incorrectly and allowed water behind the backerboards. When we dismantled the shower door (after 8 years of soaking), that whole strip of tile just fell off.
    – Zaralynda
    Nov 26, 2013 at 20:56

3 Answers 3


This is not an answer, per se, but so far has solved the issue.

I called the original tile installer to take a look. He pulled the tile piece that is to the left of the leaking grout corner. We inspected the liner and anything else we could see. The leak must have been very slow because there was minimal damage inside--no wood rot.

The exact cause of the leak could not be determined, but the tile guy sealed the liner edge behind the curb corner's vertical and horizontal tile pieces with some kind of rubberized sealant (not silicone) to make a water dam. Then used extra tile and grout mix we had to make it look new again. So far it is holding up. Then again, the leak is very slow. Hopefully, I'm not back on here in a few weeks or months with a different answer!


The leak is from inside the shower door. Take out shower door units and you will most likely see no sealant where door bottom meets tile. The sealant must be applied prior to door install.


Water can behind the tile if the grout has hairline cracks which happens over time as home settles. Grout needs to be maintained. Will will run down backboard and if the floor or pan is pitched correctly water will run to the drain and no problem. If pitched or has shifted towards a corner water can drip out of shower, behind glass, track, door and tile where it is soaked up by the drywall, baseboard or subfloor.

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