I work in an architectural office and we completed an elementary school over the summer. We have an issue in the commercial kitchen where the black furan grout is fading to gray and white. The tile in question was a thickset application using products from a major US manufacturer. We thought at first this was efflorescence, but it's been cleaned a few times and continues to get worse. At one bad location the grout was scraped out, and the full depth of the grout was now off-white, not just the surface.
Two adjacent areas - a dry storage room and the walk-in boxes - have the same flooring, but the grout is 100% fine. The dry storage room was thinset application. The submittals for the walk-in boxes suggested that this should be thickset installation, but over the stainless steel floor panels instead of a concrete slab. It's possible this was installed thinset... The concrete slab was treated with moisture-vapor reducing admixture, and a vapor retarder film was installed below the slabs.
The combination of field conditions suggests that possible moisture in the thick-set setting system is a cause, or the crew that installed the thickset floor washed it prematurely and that this is just efflorescence or polymer migration. The fact that it doesn't wash off and that it's not just surface discoloration is concerning though. We're not getting any cooperation from the tiler, the setting materials / grout manufacturer, or the GC (all of whom say it's not their issue.).
Pictures are below - while there is ample dust and debris on the floor in the pictures and the white discoloration looks powdery, it's through the whole grout depth where it was scraped out and cleaning did not remove it. I think it's been cleaned 3X now, and still persists. At this point, with the depth of discoloration in places, can we ever expect that cleaning will restore the original black color? What remediation is recommended? application of grout stain and a sealer?
I'm seeking any help we can get, since this has been going on for 6 months.
Two adjacent areas - a dry storage room and the walk-in boxes - have the same flooring, but the grout is 100% fine. The dry storage room was thinset application. The submittals for the walk-in boxes suggested that this should be thickset installation, but over the stainless steel floor panels instead of a concrete slab. It's possible this was installed thinset... The concrete slab was treated with moisture-vapor reducing admixture, and a vapor retarder film was installed below the slabs.
The combination of field conditions suggests that possible moisture in the thick-set setting system is a cause, or the crew that installed the thickset floor washed it prematurely and that this is just efflorescence or polymer migration. The fact that it doesn't wash off and that it's not just surface discoloration is concerning though. We're not getting any cooperation from the tiler, the setting materials / grout manufacturer, or the GC (all of whom say it's not their issue.).
Pictures are below - while there is ample dust and debris on the floor in the pictures and the white discoloration looks powdery, it's through the whole grout depth where it was scraped out and cleaning did not remove it. I think it's been cleaned 3X now, and still persists. At this point, with the depth of discoloration in places, can we ever expect that cleaning will restore the original black color? What remediation is recommended? application of grout stain and a sealer?
I'm seeking any help we can get, since this has been going on for 6 months.
