Is this a normal occurrence for mosaic-type floors, or is this a result of poor install?

Not sure. My first reaction is that they didn't "tamp" the floor in with either a beating block, or flat trowel. ALot of times, using mosaic tiles, either ceramic OR stone, if you don't tamp the floor in, you'll end up with the problem you're describing. Additionally, sometimes the indvidual tiles won't be bonded very well, either and it could cause problems down the way.

however, if this is a rustic type mosaic stone, or a tumbled stone, this could be the way it's SUPPOSED to be. Rustic stone is not, by definition, SUPPOSED to be perfect. There are supposed to be imperfections in the floor, and in fact, many times, you'll find stones of different thicknesses throughout the floor.

When you post pics, maybe I'll be able to tell you. But right now, the jury's out.

hey bill
thanks so much for your quick reply!

i'm uploading a close-up of the tile; it is definitely not "rustic."

i doubt that you will be able to see it in the image, but maybe you can discern the slight "dip" ??? it is not very visible even in person, unless you look closely, but when i walk barefoot on the tile, the floor doesn't feel completely flat.

i think they tamped it down, but not with something like a trowel. i recall that he was using the flat side of a piece of baseboard trim. i don't know if that is all he used. but obviously, whatever he did use did not have the surface area to ensure evenness when laying the tile.

i guess what i need to know is if this will cause problems later on in terms of loose tiles or cracked tiles, and if this is grounds for a redo... i don't want to be overly anal, since the guys seem very professional in everything else & do take their time & effort with everything. plus, i hate wasting the marble! but if they were grossly incompetent, i would have to take action & would need to know if i should make them rip it all out or just partially. sorry i am rambling, but i guess i would like to know what the "tolerance" should be for a "very good" tiling job.

Here is a link that might be useful: bianco cararra basketweave tile

It's time to beak out the belt sander. 8 )

glad you are here as well, mongo! i remember your name from the plumbing faq which was the only place on the web i could find where everything was laid out in a way that i could understand it. thank you so much for that!

what do you mean by "breaking out the belt sander"? are you saying i should literally ask them to sand my tiles level????! yikes. i am getting more stressed by the minute....

if that is really what you are saying, what EXACTLY should i be telling them to do (e.g., grit, etc.) & is this structurally necessary (will the tiles end up cracking if i don't)?

Mongo was being facetious. The very worst thing you could do is put a belt sander to that floor. It'll take down all the ridges sticking up, but you'll see it all afterward, every single place you hit with the sander.

My first reaction was right. I'll bet he didn't tamp it in. Being that this is a bathroom floor and won't get much traffic or stress, you'll probably be all right structurally. But it's a matter if you can live with all the up and down tiles, as to whether you raise a stink about this or not. I know if it were me, I wouldn't be very happy with it, but I have a feeling the installer's going to tell you at best, you buy the tile and he'll redo it.

I hit the button too quick--

It's up to you how far you want to take it. You have every right to tell him to rip it up and replace it, if it's as bad as you describe. At HIS cost.

Actually you can have the floor professionally resurfaced. Not sure what's involved in terms of grit steps or cost, as it's not something I've ever had to do.

If it's polished and you want it to stay polished, that can be a bit of effort, as the resurfacing will take the polish off, and the steps required to get it back to an even polish across the floor can be extensive.

If it's honed and you want to keep it honed, resurfacing the top is a lot easier, it could be a consideration.

Though I've not done it myself, Michael Byrne actually does take a belt sander to marble that needs leveling as this installation does.

I had a paper article that was sent to me years ago, I might even have the magazine it was in filed away. Let me see if I can at least reference it somewhere online...nope can't find the entire article, only this partial reference online:

{{gwi:1415688}}
To provide a perfectly smooth floor with these soft, honed marble mosaic tiles, the author uses an 80-grit carbide grit belt sander that is normally used for wood projects.

I know afterwards that he then uses 120 grit, I'm not sure if he continues on the belt sander or changes to a random orbital sander. I don't think I recall him going past 120 grit. It seems awfully low to me, but the photos of the finished floor looked quite nice.

He seems to know what he's doing in the field of tile, but me? I'd definitely want to experiment on some spare tile before I attacked a floor with 80 grit.

If you're interested I'll dig and see if I can find the entire article.

Since this isn't something I'm used to doing, I really can't endorse the steps. But hey, it's thrown out for discussion.

Th cost is just about the same as the initial installation. The problem with refinishing is that if the tile WASN'T tamped down, you could stand a chance of loosening alot of the tile up when they run the machines over it.

As for Michael's article, I just went right to him. Below is a link to a forum where he's the moderator, and I addressed a thread directly to him, so hopefully, we'll get an answer pretty quickly. If this is really possible, I'd be interested in it as well, because everything I've been taught as well as my experience has been a direct contradiction to this, and it'd be great if someone has a way to spot refinish without it showing up as different.

Here is a link that might be useful: Michael B.-- spot refinishing marble

thanks, guys...

i am interested, mongo, but with some trepidation...

bill, i definitely will be keeping an eye out on the link -- thanks for posting the q.

i think spot correction would be the best route for everyone involved, but i have to say, i am terrified that it will turn into a big mess! ack!

Bil are you a "JLC guy"? I used to write for them years ago. I was going to do the same thing, post over on the tile forum, but when I went to do it it's been so long I couldn't remember my login info!

I don't think the floor could be spot refinished, I'd think the entire surface would have to be treated.

I agree, and that's what I was talking about when I said the machines they use (not belt sanders) would end up knocking alot of the tiles loose.

zanne_lh-- you might want to check that thread-- Michael just answered it.

thanks, bill. i just checked the thread. i don't know if that's the path we'll end up taking (at a minimum, i'm making them pop out the patches that are the most noticeable, then retile those sections), but it's nice to know that that's an option (thanks mongo). i'll post a follow-up when/if it gets resolved. thanks again for all your help. : )

I just read this thread and realized that we had the exact same issues with the exact same tile. It turns out that the tiles themselves are very uneven thicknesses. I also had a panic attack after installation (this was two years ago). My installer wasn't a lot of help. So before the grout went in, I got down on my hands and knees and very gently smoothed the sharpest edges with some fine grit sandpaper. My husband thought I was nuts! After doing a few, my standards of what needed to be fixed relaxed somewhat so I really didn't do that much fixing. Now, two years later, with a couple of small bath rugs in there, it is fine, unnoticeable and the floor and total bath does look terrific.
Hope this helps a little.

thanks, lnmc. i am trying to relax, but every time i walk on it, my blood pressure shoots up! if it was a few isolated tiles, i would be ok, but there are a few sections where my foot "settles" into the tile. not really deeply, of course, but enough to be noticeable.

my contractor is a pretty reasonable guy, and he has patched a couple of the major sections, and a stone floor guy is coming in next week to do exactly what mongo had suggested. i will update this when all is said and done. you are so brave to take matters into your own hands!!!

crossing my fingers....

***update***
if anyone cares...

My contractor patched a couple of particularly low sections & had a stone restoration guy come in to sand it down. They sanded it wet starting with a 50 grit & went over it two more times with higher grits. I don't know what the final grit was, but they used honing powder when they sanded the final time.

The floors are much flatter; it feels like any normal tile floor, except for the edges, where they sort of "feathered" out the sanding toward the border, which didn't really need to be sanded. The only caveat is that, upon close inspection, there are fine scratches on all the tiles. Either the 50 grit was too aggressive to begin with, or they didn't hone it enough at the end. That is a little disappointing, considering that it is a brand new floor (and we are a barefoot kind of family, so it probably never would have happened on its own), but I guess I have to cut my losses at some point, and move on with my life....

Many thanks to bill and mongo for your invaluable input.

...will post pics when the chandelier is hung!

Thanks for the update. Looking forward to your completed bath pics :-)