Having recently moved into a new (resale) house, I looked closely at the grout lines on one of the tiled shower floors and noticed many small gaps in the grout lines with an unidentified orange material in the gaps. I've attached a picture.

Obviously this grout is not in good condition and needs to be replaced; however, does anyone know what the orange material in the grout lines is? It appears to be coming from underneath and is raised into the gaps between the tiles, so occupies some of the cavity where the grout would normally go.

Thanks for any suggestions.

Grout lines containing unidentified orange material

  • 1
    could be a heated floor? Could also be that someone placed spacers during the tiling process and left them in. Are they hard or soft feeling?
    – Jeff Cates
    Jun 2, 2019 at 22:38
  • Not sure about heated floor - if it is, there's no obvious way to control it. They are hard feeling - they didn't give at all when prodded.
    – mattbg
    Jun 2, 2019 at 22:42
  • 1
    Not enough grout installed. Or mixed wrong. And membrane showing.
    – user101687
    Jun 3, 2019 at 1:37
  • 13
    I don’t see grout. I only see the mortar that the tiles were set in. Jun 3, 2019 at 1:47
  • 6
    There's no grout. Either it was improperly installed, never set, and all washed down the drain or the tile job was never finished in the first place. This is the shower floor, so if the shower was being used water will have soaked through those holes and flooded the ditra underneath. Given it's ditra and assuming there's a proper amount of mortar underneath the water should not have been able to travel far, but there may still be water damage underneath.
    – J...
    Jun 3, 2019 at 12:22

1 Answer 1


Looks like schluter ditra waterproofing membrane. enter image description here

Amazon describes it:

This universal underlayment specifically designed for ceramic and stone tile eliminates the main cause of cracking in your tile installation. Tile and stone are rigid materials and are, therefore, sensitive to stresses originating in the sub floor. This uncoupling membrane allows independent movement between the sub floor and the finished surface, thereby neutralizing these stresses. Exclusively designed for ceramic and stone tile Waterproofs and allows moisture in the substrate to evaporate Replaces backerboard or a second layer of plywood 1/8 in. thick makes transitioning to other surfaces simple Ideal for interior and exterior tile and stone installations Easy to install

Below is an image of tile being installed over ditra using thinset mortar. This is as far as your installation progressed. Your floor was not grouted after the tiles were set. enter image description here I recommend scrubbing and rinsing thoroughly using a wet vac to remove water. Allow floor to dry well then grout with appropriate product.

  • 2
    This^^^. Two notes: don't cut it when re-grouting. And Ditra is generally associated with better quality installs, so you've got that going for you. Jun 3, 2019 at 1:25
  • Thanks all - would you expect Ditra to occupy space between the tiles? It looks like it would only be underneath but I don’t have much experience in this area.
    – mattbg
    Jun 3, 2019 at 1:44
  • 13
    @mattbg Looks almost like the tile was installed with thinset mortar over ditra and never grouted.
    – Kris
    Jun 3, 2019 at 1:48
  • I'm not sure what's going on here, but that's not normal looking grout, and it's not normal looking thinset either. Really looks like Ditra, but looks like there is no grout like Kris said.
    – JPhi1618
    Jun 3, 2019 at 15:02
  • 1
    @Kris: could you add "there is no grout between his tiles" to your answer?
    – Martha
    Jun 3, 2019 at 21:37

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