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jsharum
10-30-2014, 09:14 PM
First of all I want to say hello and thanks in advance for any responses. My name is Jamie and I just acquired a home with my fiancÚ in Fayetteville, AR. This is a slab home that was built in 06 I believe. I have laid a few thousand sq ft of tile in my life so I guess maybe im more advanced than the average DIY'er but not so much a pro.

Back to this house. All of the tile that was laid when the home was built is not stuck to the slab so we are removing it all and replacing it. When I say not stuck I mean not stuck. Grout line were falling apart and tile flex can be heard on many tiles and all sound hollow when tapped on. I have already ripped out and replaced the laundry room...more on that later. The thinset is very stuck to the tiles but not at all on the slab. So first question is why did it not stick? There is an abnormal amount of overspray on the slab but I find it hard to believe most tile setters that are the low bidder go and scrub a slab perfectly clean due to the hours it takes to accomplish this. Some theories I have heard is that a modified thinset was not used. The thinset froze before it set and the heck I don't know theory. Actually I know 4 more houses in thie neighborhood that this happened to. All on slabs.

Secondly is there an easy way to get the slab clean? I fear the answer is no. I used a razor scraper and DA sander in the laundry room to get the slab clean along with mopping with clean water and letting the slab dry before I laid the new stuff. Sanding creates quite the dust storm and the woman doesn't care for all the dusting afterwards.

Third. Thinset. The tile shop sold me Ultraflex 1 and I don't think I want to use this. Too late for the laundry room because its already laid with UF1. A call to MAPEI resulted in them telling me its really coverage that matters more than anything. More so than trowel size or type of thinset.

The tile im putting down is a 12x24 Vitromex ceramic. It seems pretty dang flat. Using the UF1 and a 1/4x3/8 trowel seemed to work fine. Lippage was not an issue. Im returning the rest of the UF1 and I bought Large Tile mortar by MAPEI from Lowes because Lowes said its the same an Ultracontact and another call to MAPEI said its very very similar and a good product for the 12x24. Again coverage was stressed more than anything else. Oh and im doing a 8 inch offset pattern.

As with everything in life ive received a lot of different advice and very little was similar so I wanted to pick the brains of pros and see what you all thought and what advice you all can give.

Thanks again,
Jamie

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cx
10-30-2014, 09:35 PM
Welcome, James. If you prefer Jamie you can change that in your User Profile. :)

I can't see your slab from here, but the surface contamination could be most of your problem. It's also possible that a curing agent was used on the concrete when it was finished. That can cause exactly what you're seeing.

The remediation, unfortunately, is not gonna make Mrs. James happy. Mechanical scarification is the only remedy to my knowledge.

And I'd recommend you spend some time with a long straight edge on the rest of that floor to see how flat it was. That you were able to lay those large format tiles in one area without difficulty is encouraging, but I sure wouldn't count on the whole floor being in the same condition.

The folks at MAPEI are giving you good advice, as we would expect.

My opinion; worth price charged.

jsharum
10-30-2014, 09:53 PM
If it means anything water did soak in the area I laid and did not puddle. All tiles sound good and solid. No hollow spots like the old ones!

Kman
10-30-2014, 11:32 PM
Hello, James.

Unfortunately you seem to have gotten one of the many houses in NWA that suffer from substandard tile installation. I've demolished a good number of them, many times quite easily.

One problem I've noticed that is very common is the lack of expansion joints in the perimeter of the tile floor, as well as within the tile field. It's very common for the tile that have no space for expansion to sheer off the floor, leaving the slab clean. So in addition to removing all the contaminants from the slab, make sure to leave a gap at every vertical obstruction. That gap can be filled with caulk or covered with trim.

If you have tile that run continuously for more than 15', I would also recommend that you leave a joint somewhere in the field ungrouted and fill it with a color-matched caulk.

Premier Designs
10-31-2014, 07:42 AM
It's also possible the problem was installer related ... the slab needs to be scraped of all paint and overspray and other contaminants, dust will break the bond between tile and slab, mortar could have been too dry also ..

I mop before I set, after scraping and vacuuming .. so your're doing the prep correct, it may not have been initially.

Custom's Marble and Granite is another excellent choice for large format tile.

MAPEI - Product Support
10-31-2014, 09:14 AM
Good point Dan...

We've done mock-ups over concrete, with one area swept, vacuumed, AND mopped (or damp sponge-wiped), and another swept and vacuumed, revealed subtle differences in test results, always favoring the "cleaner" slab. No one is advocating the mopping of slabs, but it is nonetheless interesting to see how that little "extra" dust can actually negatively affect (even slightly) the bond.

jsharum
10-31-2014, 02:17 PM
Thank you all for your help. Its odd to me that this floor popped up. Ive laid a number of floors right on top of old lineolium and they are stuck to this day, but a slab pops. Im just want to make sure it doesnt pop up again.

jsharum
10-31-2014, 03:22 PM
Heres a shot of the laundry room. Ill grout it tonight.