Over the past 20 years I have heard many stories about the reasons stone will fail, turn color, fade, etc. Many of these stories are funny and almost all of them are just plain false. The following is a brief synopsis of these myths and the real reason for these conditions.
Green marble warping
Many seasoned installers who have tried to install green marble tiles with ordinary thin set or other water-based setting materials have experienced warping problems. I cannot tell you how many times I have encountered the same problem as an inspector. The following are some stories I have heard for the reason that green marble will warp.
"Green Marble will warp because it contains living plant material. As water is added to the marble, the plants start to grow, which makes the marble warp." I actually heard an installer telling a customer this and about fell to the floor, trying not to laugh. I thought he was kidding, but he really believed it was the reason.
"Green marble will curl on the edges because the installer did not put enough setting mortar on the edges. The green marble will have a tendency to lift off the floor where there is not mortar and hence it will curl." This falsehood isn't as bad as the first one, but it is just as wrong.
The real reason it warps is a condition known as hysteresis. Green marble is very sensitive to moisture and when water enters the stone, it causes the marble to release any internal stress it has and hence it warps.
Stone floors and effervescence
I have lost count on how many times I have heard contractors refer to efflorescence as effervescence. Let's clear this up right now.
Efflorescence is the deposit of soluble salts on the surface of the stone. It is caused by water that carries the salts from the setting bed of the stone to the surface. It is often deposited as a white powder-like residue on the surface of the stone. Effervescence is what happens when something fizzes. A good example is when one drops an Alka-Seltzer in a glass of water. I have never seen a stone effervesce unless someone was pouring acid on it.
Along the same topic I have had so-called experts instruct people who have an efflorescence problem to seal the stone to help it. This is wrong, sealing will only block or reduce the pore size of the stone, which will not only cause more efflorescence, but could also cause spalling.
That's not a crack; it's a fissure
Now I don't want any letters or e-mails from you fabricators out there. The following is an explanation of both of these terms.