We are using polished white marble (I suppose it’s like carrera white with light grey vening) on our bathroom walls but facing some problems. Once we started mounting the tiles on the walls we have watched them change color. They were sparkley white to begin with but after they are up they start turning darker more greyish all over. All of the grey and yellowish/brown hues that were faint to begin with are really coming through on each tile. I could send you pictures if that’s helpful. I’ve waited 36+ hours and they are not changing back to their original color. I thought the water from the wet saw and adhesive moisture was doing it but they seem permanently changed. I tried getting one wet and it dried back to normal color so all I can think of is the concrete backer board (which is dark grey) and/or the thinset. Our contractor is using premixed thinset from Home Depot. It comes in plastic buckets. The color is called ‘white’ and looks white to me, not grey. So I’m confused and unsure if we should tear everything down and start over, or if even the ‘bright white’ thinset sold by some of the tile stores will do the same thing.
We have not sealed the tiles yet because I’m wondering if there’s anything that can be done to restore their original sparkley white color before we seal. Any recommendations on what to do (if anything can be done) and the best sealer to use before we grout then seal again would be appreciated!!
Jill (Denver, CO)
The marble is just really soaked from the moisture in the thinset and it is trying to dry through the tile. The marble tile is more absorbent that the subfloor so this is path of least resistance for all the moisture in the thinset.
Sealing the marble before installing it would have been a disaster and created and permanent problem. Basically, you just have to wait and wait and wait. The tiles will dry at the corners fist because they have the most exposure to air. Because the marble is rough on the back, the water enters easily. However, because the tile is polished on the surface, it struggles to penetrate the surface.
You can also accelerate the drying by renting a large commercial blow dryer which is usually available at equipment rental locations. Somethime they are called ‘salamanders’. They usually run on propane but some may be electrical. You will notice results within a few hours. This works as I have done it myself. Otherwise, you need to wait a couple weeks at least for the marble to dry out before sealing it.
Best wishes and let me know how it turns out!