Hi Tom,
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)

Hello Jill,
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!

Hi Tom

We are having our bathroom tiled with Carrera marble. We have requested our builder to fit the marble as tight as possible so that it has a ‘seamless’ finish rather than with visible grout lines between tiles. The marble supplier told us that this is possible and recommends cutting playing cards to act as spacers between tiles. However, our builder does not believe that you can fit marble without a wider grout line. Please could advise on how to achieve the ‘seamless’ finish and what grout should be used?

Thanks and regards,
Mariam.

Hello Mariam,

You can put the tiles tight together but you will most likely have to grind down the interior floor afterward because it is almost impossible to avoid slight lippage between the tiles. Marble tile are not cut perfectly so even a normal 1/32″ variance will feel like a lip when tiles are butted together. For this reason, I strongly do not recommend butting the tiles together.

I really don’t feel that your supplier knows what he is taking about and using a playing card is just silly. You should install them with 1/16″ joints and use non-sanded grout. For white marble, I strongly recommend using epoxy grout because white ‘cement-based’ grout is impossible to keep clean.

Your white marble has veins so there is no hope for getting a ‘seamless’ look. Once the joints stop and start between the tiles, it will not appear seamless. If you have a good installer, then 1/16″ grout joints will look even better them butted joints because the joint makes for a nice ‘planned’ transitional pattern in the floor or wall.

Best wishes,
Tom Cordova

My wife and I are designing a pool which will have a planting area as a wall of the pool. The planting area will be covered with marble but we are not sure how the chemicals of the pool can affect the marble. If not marble what other durable choices we should consider?

Robert

Hello Robert,

There are several things to consider here. Some new pool systems clean the water without the need of routine Muriatic Acid treatments. If this is your design, then that eliminates one of the problems with using marble around pool areas. This acid is basic commercial granite Hydrochloric Acid. If your pool design requires this acid or any other acid that reacts with calcium carbonate (marble), then keep in mind that the acid(s) will literally dissolve your marble.

In addition, even sunlight and air pollution will noticeably damage the finish on marble within a year or two. If you do not desire an ancient weathered look, then do not use marble outside and especially not around water features that are designed to required acid treatments.

My recommendation is to use granite. Muriatic acid and sunlight will not harm granite at all. There are hundreds of colors that you can see on www.GraniteStock.com and I am sure you would find one that you like. Note, that a few exotic granites are coated with polyester resin at the factory. Do not use these granite colors outdoors because the resin will deteriorate and ‘yellow’ from sunlight. Just ask the supplier if the granite you like is resin coated or not.

Best wishes,
Tom Cordova

We have purchased marble for our shower – it has unfinished edges – can you stain them or what is the best way to finish them?

Mary Ann

Hello Mary Ann,

You need to have the edges polished by sanding. You need to start with a high speed rotating sander and 80 grit sandpaper. The use 120 grit, then use 240 grit and finally 360 grit sandpaper will bring out the luster. Otherwise I recommend you count the number tiles that you need the edge polished and take them to a fabrication shop and ask them to polished the edges for you. They will do a much better job.

Best wishes,
Tom Cordova