Hi Craig
Sorry for the delay in getting back to you on your post. I found out about it yesterday but haven’t had a chance to respond until now.
From the pictures it’s very hard to see/tell what’s going on for me. For instance in the first picture (under that piece of furniture) the “pattern” appears to go across from one tile, across a grout line and is continued onto the next tile. If that’s the case to me it would indicate that something has gone from the top down, as in being spilled or poured onto the floor – like being improperly cleaned; most often with vinegar, TSP (Grout Haze Remover) or some other acid. Vapor migration won’t normally come up through two different tiles in one continuous pattern like that. As to pattern, the same thing goes with pictures 2, 3 & 4; what ever is going on is doing it across almost the entire tile with only a few small places if at all where the tile looks normal. How long has this tile been down and has it always had this appearance? If the floor always looked like this from day one or very shortly there after I’d say someone tried to remove grout haze as if they were trying take it off of ceramic tile and etched the stone.
Also notice the grout, true there is a small measure of “ashiness” in a few areas, for the most part it looks fairly consistent. Grout is way more absorbent than the stone is going to be. It is also going to let evaporation pass through it at a greater rate than the stone will. That being the case it would seem there should be substantially more deposits on the grout then there is on the stone, there should be large clumps of crystals along the grout lines and they’re not there.
Let’s say for a second that it is efflorescence. Efflorescence is not the problem it’s a symptom. What the problem is, is that there is moister/water getting behind the stone somehow, evaporating and bringing with it minerals that get left on the surface. You can do your best to mask the problem but I feel pretty sure that in time there will bigger and more serious problems. Try this; take a piece of visqueen, heavy plastic or even a large kitchen garbage bag. Lay it out flat on the floor and tape down (completely seal off) the edges. I would normally never encourage you to tape anything to stone because the adhesive on the tape can have acid in it and it can etch the stone – in this case that’s the least of your worries. Give it at least 24 hours or more and then first inspect the plastic without disturbing it. Can you see droplets of water collecting on the underside of the plastic? If you can’t see anything then try removing the plastic, do the tiles that were under the plastic look wet or even damp? If so then there is a very good chance that there is a serious moisture problem with that floor and you could in fact be seeing efflorescence.
In the end how are you going to fix the problem? If it is efflorescence adding water to the floor is only going to exacerbate the situation but you won’t have too much choice. Clean the surface with an aggressive pad, I’d suggest using a very aggressive strip pad (often called a High-Pro or Lightning pad) that gets used for stripping VCT. Apply a neutral cleaner, scrub the floor and get it picked up ASAP. If you’re using a high pressure recovery system I’d turn the PSI way down. Put an air mover on it and get it dry a fast as you can. Allow it to dry and apply a very good quality penetrating sealer to it. I have had very good success in this situation using a product called Stain Proof. You could also try using honing powders to mechanically abrade the surface and remove it that way but I wouldn’t recommend it. You’ll need to have the stone wet for too long and I don’t think you’ll get the effect you’re looking for. If the surface is badly etched (which is what I think is actually going on here but it’s hard to say without inspecting it personally) then I’d suggest resurfacing the floor with diamonds, bringing it up the desired appearance level and sealing it.
David Gelinas
Marbleguy
PS Dang I need to type faster, that only took 1 hour 12 minutes.