Replies

1. 
   Mongo | Jan 04, 2014 12:50pm | #1

   I recommend thinset

   An issue with mastic and marble is that marble is porous and mastic can stain into the thickness of the tile. The front surface can and up looking mottled, blotchy, and discolored. So I recommend a true thinset.

   As far as thinsets go, use a white thinset. Gray thinset can sort of muddle the brightness of marble.

   If you use a notched trowel to apply the thinset to the wall, make sure to fully compress the thinset ridges when you set the tiles so you get full thinset coverage on the back of the marble tiles. Sometimes uncompressed thinset ridges and valleys can shadow through marble.

   Be aware that after setting, the marble may absorb some of the moisture from the thinset. That might cause the marble to darken. It might be a uniform or blotchy discoloration. But after the thinset has fully cured and the marble has dried out, the marble's brightness should return. 

1. 
   moosehead333 | Jan 04, 2014 01:40pm | #2

   Thanks, good things to keep in mind.

1. 
   Mongo | Jan 04, 2014 08:56pm | #7

   my apologies...

   ...in that I never recommended an adhesive.

   As I wrote earlier, I recommend you avoid mastics. If you go to a box store and they try to sell you a "premixed thinset" that comes in a resealable plastic tub, avoid it. It's mastic.

   Use any modified thinset. Dry powdered portland cement based thinset that comes in a bag. A lightly modified or a heavily modified will do you fine.

   Of you use Laticrete, use something along the lines of 252, 253, or 254. If you shop at Home Depot and want to yse Custom's thinsets, use VersaBond or FlexBond. Flex is more modified than Versa.

   For an interior installation in a decorative setting, a lightly modified (252, 253, or VersaBond) will save you a few dollars and give you very good performance.

   Or you can buy an unmodified thinset and modify it yourself by mixing it with a liquid latex admix. But the already modified in a bag will probably be easier and less expensive.

2. 
   Mike_Mahan | Jan 04, 2014 02:49pm | #3

   Green marble

   If the marble is green (color not unripe or non poluting) you have to use epoxy thinset.

1. 
   sapwood | Jan 05, 2014 12:33pm | #9

   Why is this the case with green colored marble? And, if true, what was used before epoxy was created?

1. 
   Mongo | Jan 05, 2014 07:51pm | #10

   The Rainbow of horror...

   "Why is this the case with green colored marble? "

   Green "marble" which is often a serpentine is the most common stone that is moisture sensitive. I've heard black and red are too, though I've never installed either. Don't know if I've ever even seen red marble.

   Green itself? Exposure to moisture can relax some of the internal bonds within the stone, causing the stresses within the stone to show themselves and warp the tile. When it dries, it may indeed lay flat, or almost flat again. But the repeated flexing can cause the stone to exhibit a sort of scale. You drag your fingernail over it and it's sort of rough like the edge of a deck of cards that is slightly fanned out. The flexing can also cause small pieces to break off, the stone can be covered in a fine grit.

   Moisture sensitive stones need to be set with epoxy, as epoxy does not contain water. Thinsets do contain water.

   Once properly set with epoxy, water exposure will not be a problem. The strength of the epoxy bond will prevent movment.

   When you buy, you simply have to ask if the stone is moisture sensitive. Not all stone sold as green marble is indeed true marble. Nor is all green stone moisture sensitive.

   "...what was used before epoxy was created?" I have no idea.

3. 
   robcon | Jan 04, 2014 04:58pm | #4

   marble on sheetrock

   I would worry about the weight of the marble pulling off the paper. I would first install non concrete backer board with  countersunk screws, then install marble with thinset. I saw too many mastic failures in Florida, especially in baths.

   Robcon41

1. 
   DanH | Jan 04, 2014 07:18pm | #5

   Aw, what could possibly go wrong?

   (I recall seeing some pictures here a couple of years back where someone had done a bathtub surround with something like slate.  It jumped off the walls several hours after install and smashed the cast iron tub.)

2. 
   Mongo | Jan 04, 2014 08:19pm | #6

   "I saw too many mastic

   "I saw too many mastic failures in Florida, especially in baths."

   With mastic being water soluble, that's not a surprise.

1. 
   moosehead333 | Jan 05, 2014 11:52am | #8

   I'm going with thinset. The marbel is tan so I won't have the expoxy requirement. And if the marble is exposed to water, I'll have bigger issues to deal with than teh drywall coming apart.

   THANK YOU for the help.

1. 
   Mike_Mahan | May 30, 2016 10:47am | #12

   Nevermind

   nevermind

4. 
   easternceiling | May 30, 2016 06:49am | #11

   (post #209064)

    Although there are drawbacks with mastic, there are advantages. Mastic has superior holding strength, easier to apply, and sets quickly. When used to tile walls it’s strength allows you to set tile, and if you’re good with eyeballing, you can set tile without the use of spacers. If you attempt to set wall tiles using thinset without spacers, you’ll end up with a bunch of tiles that have slid into each other before the thinset has had time to set, resulting in a giant mess.