Has anybody else heard of this one . - TilersForums.com

[Dumbo]

I heard In the tile shop that I use another trader went in enquiring about the price of Mapei ucp because they were having trouble with colour of red biscuit tiles bleeding into bal micromax grout .

 

[Andy Allen]

I've had the red biscuit show on the edge of the grout with cheap ceramics because the glaze dosn't go to the edge of the tile, would of thought you would get that with any grout though..

 

[Tile Shop]

I would have thought that would only be possible if the clay back was pigmented and a slowset or dispersion adhesive was used and grouted too soon. Can't see why it would discolour one make of grout and not another. Or even the tile was underfired and was still a bit chalky and some residue contaminated the grout?

Did see grout discolour once when the plaster behind got wet after a leak. White grout went pinky. Slighty discoloured the tiles to so maybe more to do with a dodgy background than the tile?

Who knows. Loads of reasons why grout can discolour.

 

[Lairdy1]

Ive seen charcoal black grout turn electric blue and im not kidding. Even the rep who visited and did all the tests ect was baffled. Had to stain the whole lot with pure charcoal dust and water.nearly 200mts of it.