Porcelain tile on concrete -- some general advice needed

Have you considered concrete polishing? I had the same flooding problems with my basement. Instead of tar, I had the sticky remains of a rug pad and uneven concrete. Polishing smoothed out the surface and it looks great. Most people think I laid out a granite floor on my basement. It’s also very easy to maintain and clean. In my case, concrete polishing cost just as much as laying out new tile. I hope this helps.

Many thanks!!!

This is like a test: “Which item on the list is not part of a set (A, B, C, D, or E)?” The correct answer is D, Ditra. That is an uncoupling membrane made of plastic, A -C and E are Portland cement products. Ditra is used between your substrate and your tile. It is the orange waffle stuff, if you watch home improvement shows. Your pictures show an intact substrate, but it is hard for me to evaluate condition from these surface shots. I don’t see obvious unstable cracks, but I can see the result of the flood: Your asphaltum adhesive appears to have lifted off the concrete in places, but not other places. It looks like vapor pressure has released the bond in a vague puckered pattern. Check out this video of a guy demonstrating his solvent and methods of removing the same gook you have: http://www.youtube.com/watch?v=AKPbhywRdcA. I noticed when the guy started, his concrete floor was completely covered with the adhesive, it doesn’t look like yours. But, you too will have to remove it and it looks like a messy job. The Ditra will help. Read about it on Schluter.com. There are also videos showing how to install it. A good tile setter can get this from a trade outlet, not the small rolls sometimes available at Home Depot. “Uncoupling” refers to the way Ditra attaches to the substrate, and the other side to the tile, and allows movement between. And, that is important, but Ditra also has air channels running under your tile. Allowing vapor to escape from normal ground moisture, or… Flooding in basements happens all the time. This could save you from repeating this miserable experience. Vapor pressure from wet concrete is strong enough to release the stickiest impermeable adhesive, as your pictures suggest to me, and strong enough to push impenetrable porcelain tile up and off from below. I don’t work for Schluter, but they did put me up in a hotel for a few days while they trained me. Not everything among the remaining items makes any sense. If you had a flat, stable, concrete floor before, that is your substrate. You can and should use it again. But first, you need to remove the impenetrable tar, asphaltum, adhesive, whateveryoucallit, off. Completely, clean off. I don’t know the product shown in the video. It is probably a really, smelly and unhealthy chemical, but interesting that it mixes with water. That this product exists, suggests a lot of people are dealing with the same problem you have. You can find me in the directory under tile and stone, or shower stalls. Obviously, I think the person recommending Ditra is on the right track. I can’t tell you more without seeing it, and I am not sure I want to see it. If that person is also the most expensive, that would increase my confidence. Tile is a capital improvement. If done right, it will become a permanent feature of your property. You are correct, in noting a lot of opinions are out there. Engineers have studied these issues in laboratories and in field tests, and made their findings known in the tile and construction industry. Tile setting is not a matter of opinion, or a mysterious craft. It is also not intimidating or hard to understand. If you are confused, perhaps the person explaining also doesn’t get it. “We do it this way, because we always do it this way,” is not an answer. You can see tile failures in basements, subway stations, showers, dry areas too, but you can also see where jobs are done to last. Where liquid water and water vapor are not accounted for, you can see a lot of tile failures. Green Mountain.