And when things go wrong, such as the tenting of our kitchen tile, a decision has to be made...
Should the broken tiles be replaced? Or should we do something a bit more drastic...
In the case of our floor, the tiles began to buckle in a couple of small areas, then began to spread to a much larger area, creating a trampoline effect. How it began is unclear, though we suspect part of the reason is the tiles had not been sufficiently adhered to the slab underneath. And there did not seem to be expansion joints to allow movement caused by changes in temperature. Still, the tenting occurred with no warning.
It has been said, tented tiles can spontaneously explode if the pressure is not released by removing the affected tiles. Tile-shrapnel doesn't sound very appealing. So, we decided to remove the tile. All of it.
This was no easy task. But not impossible when armed with a hammer and a screwdriver. The tile lifted fairly easily, with thinset mortar stuck mainly to it and not to the slab below. With a screwdriver or chisel, the remaining thinset was scraped off the slab. All told, I only got one blister... Wellll, okay, it was a blister on top of a blister. Not a pretty sight.
The plan was to expose the slab and prepare it for staining. This seemed to be the natural thing to do, as we did not relish the idea of installing more tile or any other type of flooring. Stained concrete is by far more economical and easy to take care of.
What we weren't expecting was the black sticky cutback adhesive that had been underneath the tile and thinset. This stuff wouldn't budge. And, because it has been known to contain asbestos, it had to be dealt with wisely.
The best solution was to use a concrete primer that is made for sealing cutback and creates better adhesion for fresh concrete. On top of that, we poured self-leveling concrete underlayment to create a clean surface.
The husband poured, I troweled.
Self-leveling concrete sets very quickly. Though I worked as fast as possible in small sections, it was difficult to create a perfectly smooth surface. Which actually created a good end-result, since we wanted a more stone-like look.
The concrete was allowed to cure for nearly a month. It is recommended that fresh concrete should be cured for about 30 days before a concrete stain is applied. Self-leveling concrete underlayment cures faster than regular concrete, though we didn't want to take chances. That, and we were busy with loads of other goings on!
The next step, was to overcome the fear of staining the concrete. Once it's done, it's basically... done.
Whilst I truly wanted a proper acid stain, which would change the color of the concrete chemically and permanently, the cost was too great. Instead, we opted for an acrylic semi-transparent concrete stain, which is almost like any other acrylic paint though much more watery. It doesn't stain concrete quite as permanently as an acid stain would.
Acrylic concrete stain is a bit tricky to apply, in that, if one applies too much it looks like paint sitting on top of concrete instead of a stain that has penetrated the pores of the concrete. Not attractive for semi-transparent stain. It will also have the tendency to peel off if over-applied and not properly sealed. Even so, acrylic concrete stain is otherwise easy to handle and easy to clean up from tools and hands with a bit of soap and water.
To prepare concrete for staining with acrylic concrete stain, an acid etching is recommended. This cleans up stains and oils from the surface and opens up the pores of the concrete, so it will better absorb the color of the stain. The process is completely different when using an acid stain.
Acid etching is not recommended for acid concrete stain. An acid stain needs to chemically react with the lime at the top layer of the concrete in order to create the color. Acid etching removes this lime layer, so the desired chemical reaction can not occur.
Okay. Back to the fix.
We acid etched the concrete following package directions. Then, instead of rinsing with water, as recommended on the package, we sprayed on a mixture of baking soda and water to neutralize the acid, squeegeed and shop-vacuumed the slurry. After which, we mopped... and mopped... and mopped. Until the surface was clean.
After a day of waiting for the floor to dry, we got out the paints.
Three colors were chosen. Charcoal, a greenish-blue and a "chicory" color. These we applied with large sponges. Blending vigorously, pushing the color into the concrete. We did it this way to create a softer more natural effect. Carefully avoiding overloading the sponges with too much paint.
It took a long, long...long time.
Once that was done, time for a concrete sealer. For the kitchen, "wet-look" was chosen. Three layers of it. I just finished the last coat. Whew! Almost done.
It's drying now, as I type. Yes, I work at night. Ha! After that, a few coats of acrylic wax to protect the sealer and our floor-fix will be complete!