Granite Tile Discoloration during installation

russ2008 · 10-05-2008, 04:26 PM

I need help with a discoloration problem I'm having installing 12in Madura Gold granite tiles on a bar countertop
Here's the steps I've taken:
1) 3/4in plywood base
2) Hardibacker Backerboard, screwed down.
3) Mixed Thinset from Lowes using brand Laticrete 220 Marble & Granite White Mortar
4) Spread thinset on backerboard using a 1/4in trowel and backbutter the Madura Gold tile and bed in mortar.
The problem is that after 30 minutes the face of the tile dramatically changes color, as if it's in the process or curing and stays that way. I've waited 24 hours and face of the tile is still discolored (went from a light colored tile, to a dark color tile).

What am I doing wrong? And are the tiles salvagable somehow? I'm starting to get a lot of money tied up in this project.

Bud Cline · 10-05-2008, 04:46 PM

Calm down, calm down.

What you are seeing is simply moisture from the thinset that has permeated the stone. It will go away, but not in twenty-four hours. Depending on atmospheric conditions at your location it could take a couple of weeks to dry out. It happens all the time.

WHATEVER YOU DO - DON'T apply any sealer to that stone until it has dried completely.

You can also expect the edges to darken from moisture after you grout.

Be patient.

russ2008 · 10-05-2008, 08:24 PM

Whew!

Bud, Thanks so much for the quick response and easing my fears.

I haven't sealed the tile yet, or grouted, so I'll wait. I'll plan on giving the tile the time it needs to dry out.

The local Home Depot tile person mentioned sealing the back of the tile PRIOR to installation, but I don't plan on doing this. Nothing I've found in researching has indicated sealing the back of the tile before beding in mortar should be done.

I plan on taking your advice and am confident things will turn out just fine.

Thanks,
Russ

Bud Cline · 10-05-2008, 09:30 PM

You never want to seal the back of any tile, this would only compromise the bond. I don't know where those characters get some of the nonsense they so willingly give to people.

gallen · 03-01-2009, 08:28 AM

My granite also discolored....Can I grout before the color comes back? VER PANICKED

buletbob · 03-01-2009, 08:38 AM

Quote:

Originally Posted by russ2008

Whew!

The local Home Depot tile person mentioned sealing the back of the tile PRIOR to installation, but I don't plan on doing this. Nothing I've found in researching has indicated sealing the back of the tile before beding in mortar should be done.

I plan on taking your advice and am confident things will turn out just fine.

Thanks,
Russ

your best bet is not to listen to the sales person in these big box stores, There are some smart sales people working there but mainly in a higher up position, the one's on the floor were mainly self employed contractors who could not make it out on there own.

I see this all the time.

WallY Z · 03-06-2009, 10:51 AM

I am having the same problem. Can I grout the floor before it is completely dried or do I have to wait until it,s dried.

Quote:

Originally Posted by Bud Cline

Calm down, calm down.

What you are seeing is simply moisture from the thinset that has permeated the stone. It will go away, but not in twenty-four hours. Depending on atmospheric conditions at your location it could take a couple of weeks to dry out. It happens all the time.

WHATEVER YOU DO - DON'T apply any sealer to that stone until it has dried completely.

You can also expect the edges to darken from moisture after you grout.

Be patient.

JazMan · 03-06-2009, 12:42 PM

You can grout the granite before all the moisture goes away. I would wait an extra day or so if possible though. Just wait a few weeks to seal the grout. The trapped moisture would still evaporate thru the grout and sealer, just a bit slower.

Hey BuletBob, You're implying that there is someone at those stores that are true experts in the use and installation of ceramic tiles. Will you please let everyone know at which location he/she can be found?

Jaz

paul s · 04-28-2009, 06:27 PM

I had installed granite tile for a shower enclosure over cement hardy backer board. It is Perla Rosa granite - a very light grey color with pink and mica flecks. The adhesive used was Tile and Stone Adhesive recommended by the tile store - not a thinset but it is described as a mastic. Mastic was applied with a trowel. Almost immediately the tile became dark and discolored. The mastic container said not to use on water sensative stone but that is what was recommended by the tile store. Using a fan on the tile, I gave it almost a month to dry but when it did not, I contacted the tile store who were intially sympathic. They even contacted the mastic representative but then became unwilling to assist with any abatement and blamed the tile installer. I have a service now with a dehumidifier and 3 industrial fans attempting to dry out the tile. Some tile are getting lighter and some are showing movement of the water with the development of serpiginous, almost geographic areas. i have had the fans and dehumidifer in the room for 5 days now

and it is about 105 degrees in there. What is the prognosis for the tiles. Any advice is appreciated. The tile company is a nationwide retailer so I will not name them but can provide more information if needed. Many thanks.

Bud Cline · 04-28-2009, 07:31 PM

See if the "mastic" label reports the chemical contents (makeup) of the mastic and determine if any of those ingredients contain any oils. Do you see where this is going?

paul s · 04-29-2009, 04:06 PM

here is the link to the Product info and MSDS sheet:

http://www.northamericanadhesives.ne...ds/NA_2300.pdf

http://www.northamericanadhesives.ne...00D_A08Evp.pdf

Many thanks for your quick response!!

ccarlisle · 04-29-2009, 04:50 PM

It says right there 'not for shower floors'. Take it out and do it right.

Or take a number of showers and watch as the mastic dissolves away down the drain, then just pick up your tiles...

Don't waste your time trying to find ingredients in US MSDSs. Half of them are phony or 'hidden' ingredients anyway...and certainly not from Mapei. They're too big and too good to give you their recipes. The best you'll learn is that a mastic contains a PVA resin.

That's like saying "My Rolls-Royce has an engine..."

paul s · 04-29-2009, 04:58 PM

this is for shower surround. not floor.

ccarlisle · 04-30-2009, 07:37 AM

Oh, OK Paul s, my bad. I just assumed your shower included the floor.

But the gist of my reply remains. The fact is that mastic is an organic adhesive usually in the form of an emulsion of PVA resin in an organic solvent carrier. A bit like a paint...without colour.

I am not sure of the water content of mastics (if any) but I can say that the solvents may or may not fully evaporate once the resin has polymerised to form the adhesive function. But either way, it is water-sensitive, so much so that running water, or high humidity, with time, will break it down. So it's fine for a backsplash - but nowhere near a shower.

And although I have nothing against mastic as a product, there was a time when the advertizing would not specifically say "not for showers" so a lot of people got burned when their tiles just fell off. It's better nowadays but the wording is very well selected, IMO.

The evaporation of the solvents in mastic will affect the look of the tiles especially if the tile is anywhere absorbant. Solvents have lower surface tension than water normally and therefore can 'wet' a surface easier. This translates into more or less visibility of stains through the tile. Now some stains may disappear with time but the whole concept of staining just shouldn't be an issue than a tile setter should hang his hat upon IMO.

We know thinset and how it works. Mastic is a different horse...

Vinnieman · 03-26-2013, 11:32 PM

Is ther anything you can do if you've alredy applied sealant to granite, and moisture from the thinset has soaked through? Is there anything I can apply to the granite to reverse the sealing effect? Or is there a possibility the granite will EVENTUALLY dry out? If anyone has a possible solution, please help?

Yours trully, idiot DIYer