Porcelain Tile vs. SoCal Concrete

[2CWG]

Given the success many here have had with porcelain tile, it is my first choice for an ongoing garage renovation. The combination of durability, easy maintenance and upscale look creates a solid driver. Unfortunately, predominately clay soil and California's penchant for earthquakes give me pause.

We recently moved into a 12y old home and the post-tension slab is showing some cracking (pics below). Most are horizontal, although one section does show roughly 1/16" vertical displacement. Not certain if the concrete has been treated in any fashion, but the surface finish is very smooth. Water will sit on the surface for ~5min, but will eventually soak in.

I'd appreciate advice on the feasibility of this project based on the current slab condition and environment. Any thoughts on crack isolation and pre-installation leveling would also be welcome. Of greatest concern is the vertical displacement near the crack junction featured in the close-up shot .

Threads from Dakota, Jack, JimVonBaden, slickgt, nicobkn, bdamico and many others have helped immensely in narrowing down tile attributes, thinset brands and many other parameters. My thanks to all who've taken the time to record their journey.

Overview. You can see the a few of the larger cracks and some spiderwebs. Note the previous owner's attempts at repairs (discolored bands following the cracks:

Nice stamped warning regarding the slab. Fairly common in houses I've seen out this way:

Closer view of the most badly cracked section near the junction of several faults. Note the ~1/16" vertical displacement boxed in red:

Another angle of the displaced section:

 

[Paultergeist]

I have no answers, but I share many of your questions. The best parts of my two-car garage slab are on par with the sketchier part of yours, and I am in SoCal as well (San Diego County). I will be watchng this thread with some interest.

I already have about 1/3 of the tile I will need to cover my (roughly) 20 x 20 garage floor [left over from other projects], so I am leaning heavily in the direction of porcelain tile.

Please keep us posted.

 

[Dakota00]

I'll provide my opinion...
Clean out the cracks good, inject epoxy "crack repair" into the cracks, let it dry.
Next rough up and degrease the area around the cracks, let dry.
Apply at least 2 coats of a liquid crack isolating membrane like RedGard or AquaDefense 12" on either sides and on the cracks. Let it dry for 24hrs.

Now you are ready to tile the floor, I would highly suggest using thinset with a flex agent already added to the powder like Flexbond found at Home Depot
http://www.homedepot.com/p/Custom-B...ied-Thin-Set-Mortar-Gray-50-lb-FB50/100122448
Or you can go with the latex additive mixed into the thinset with Kerabond/Keralastic System from Mapei, it's a more expensive but well worth it.

 

[Track t-4]

Dakota00

How does the crack isolating membrane work? Does it stop the crack from widening? It sounds like a rubber substance, does the tile/mastik stick to it? What does it do with respect to the crack? The tile?

 

[2CWG]

The pros will likely have a more complete response, but while researching for the project I ran across the following:

What is an anti-fracture membrane?
The internal make-up of this membrane is such that movement in the concrete is not directly transferred to the tile. Although the membrane is bonded to the concrete and the tile to it, the membrane stretches where needed to prevent or reduce force transference. These membranes are either trowel applied or sheet applied. In many cases, multiple components or steps are part of the system. Performance varies also - it is important to check with the crack isolation membrane manufacturer regarding their installation instructions and intended use.

Source: http://www.tcnatile.com/faqs/24-crack-isolation-membrane.html#faq5

 

[Dakota00]

Dakota00

How does the crack isolating membrane work? Does it stop the crack from widening? It sounds like a rubber substance, does the tile/mastik stick to it? What does it do with respect to the crack? The tile?

The crack isolating membrane doesn't stop cracking or shifting in the slab. The membrane is basically a "shield" or an absorption layer which will absorb any movement resulting in cracks. Which minimizes the chance of the tiles and/or grout work from cracking.

Once the liquid membrane is applied and then dried. Thinset is applied in the normal fashion for setting tiles.

 

[85camaro]

I would advise against putting tile on that slab. However, if you do, use flex guard over the large cracks, and an isolation membrane will suffice for the smaller cracks. And yes, even a hairline crack needs isolation membrane.

Thin set should be a kerabond with keralastic mix. If you take all of these steps and apply the anti fracture material correctly, it will give you a fighting chance of avoiding cracked tile. However, there isn't much you can do to avoid hollow tiles once movement begins.

 

[slickgt1]

I would fill those cracks. Paint on isolation membrane. Install tile on top without even worrying of thinking twice. Seriously what do you think will happen? Tile will be jumping off? You going to get holes or cracks in the tile? No. And if you do, its not like the repair will require you to redo the whole floor. Tile repair is easier than Sheetrock repair.

 

[breeaad]

Disclaimer: I am no tile expert. But I have laid several floors and I have repaired several cracked floors where shoddy prep caused cracked tiles.

if that were my garage, I would not lay a tile floor. That slab has settled, causing it to crack. It will continue to move over time. This movement, in my opinion, has a high likelihood of cracking tiles in the future. Now while removing a cracked tile, leveling the floor, and replacing with new tile is not that big of a job, regrouting the entire floor is. If you don't, you will end up with grout that doesn't match, and the repair will stick out.

I can totally see where some would lay tile and worry about it later. But myself, I would like to avoid that future repair hassle. And there WILL be future repairs!!!!

 

[slickgt1]

I still say do it. Isolation membrane a must, but if it doesn't move when you drive a car on it, i would not worry.

If you are replacing a few tiles, why would you Re-grout the whole thing? Save a box of grout. This is a garage after all, who cares if its a shade different. This floor will still be stronger than most options.

I'm no expert, but I've done a **** load of tile. I will tell you, my floor was worse. A section moved when i walked on it. Perimeter lower than center, settling. Looked like i had two separate pours. No barrier. Drain ditch infront of garage. North east. As soon as Jack O recommended tile for me, it all clicked and i never looked back.

I poured columns into moving section. No isolation membrane. Cheapest thinset. Sand and cement for mud job. Fill cracks, no. Remove paint, no. Ask me if anything cracked in 3 years.

If you do what Dakota suggested, it will be a more pro install than what I have.