The grout of our tiled bathroom floor (approximately 8 ft x 6 ft total area ), installed some years ago prior to us purchasing the house, appeared stained in various ways, ranging from a sandy white to a dark brown color. The grout also seemed poorly installed (though I have no experience in this), with grout reaching the top of the tile and in parts even covering part of the tiles. We decided to use Polyblend Grout Renew to color (lighten) and seal the grout, a process that's been going just fine with the overall look much cleaner.

While working on staining a section of the grout I noticed that some grout had chipped off (circled), uncovering what looks like another layer of rough, grey grout beneath. This made me wonder whether the entire installation had for some reason been grouted twice.

My goal is to stain and seal the grout on the entire floor. My questions are:

  1. If this top layer indeed is grout, is there a structural reason why it might have been (so poorly) applied in the first place?
  2. Would it be worth trying to remove this upper layer prior to staining?

Removing this upper layer seems like it would be a lot of work (the tiles are 1.75x1.75"), but the result might look cleaner. Staining and sealing the grout as is however looks just fine to me.

Image of the tile floor pre and post stain+seal Small region showing in red region where what seems like an upper layer of grout has come loose showing a base layer of grout

  • You've got several problems going here; the grout was obviously installed by someone inexperienced and/or extremely sloppy, and it looks like they used unsanded grout which probably contributed to the failure. If those tile are 1 3/4" then the grout joints are at least 1/4", that requires sanded grout. Jun 13, 2020 at 23:02
  • Thank you for the insight, really useful to know Jun 15, 2020 at 16:28

1 Answer 1


That layer below is likely the normal tile adhesive.

The grout is the finishing layer above that, so that broken or missing part should be regrouted.

There are tools for removing old grout. You can do as little or as much as you feel you need, but I would just repair faulty sections if there are only a few. When most are faulty then you have to do all of it.

  • "Grout Saw" is a good tool search term.
    – Ecnerwal
    Jun 14, 2020 at 2:50
  • Thanks for the information. Given all this feedback I think I'll plan on doing limited repairs in conjunction with this stain and sealing project, and will keep a full re-grouting in mind either when extensive chipping occurs or in conjunction with other remodeling Jun 15, 2020 at 16:31

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