By Ray Thompson, Jr.
As a retired floor layer, I bought the house next door and planned on remodeling it. Part of the plan was to move walls and update the entire structure within. This was done without any problem. When it came to the floors it was another story. The house was constructed on a concrete slab in the desert area of the Southwest in 1972.
In the living room the concrete had settled about 1/8” on one side which caused the existing ceramic tile to crack across the width of the room. When I removed the ceramic tile, what appeared to be alkali salts were along the concrete crack making me think there could be a moisture concern. Also, the ceramic tile was poorly adhered.
In the living and dining room, further observation revealed that there had been vinyl asbestos tile installed with cutback adhesive. Later, the vinyl asbestos tile was removed, and carpet was installed over the cutback residue. Then the carpet was removed, and ceramic tile was installed over the cutback residue. The thin-set mortar was not sticking to the cutback particularly well.
The other area of concern was the kitchen, which featured a heavily embossed inlaid sheet vinyl—likely an asbestos backing from the era in which the product was installed.
Ceramic tile. Ceramic tile was a 12” x 12” ceramic installed over a cutback adhesive residue, which had asbestos since this was original floor was done in 1972. While the majority of the ceramic tile was installed over cutback adhesive there was a small, hard-to-remove portion with no cutback adhesive. Here, it took a lot of manpower.
Skim coat. With cutback adhesive, asbestos was not removed from the product by manufacturers until 1979. Since the bond of the thin-set to the cutback was poor, the tile came up easily. We were careful to not break the encapsulation of the asbestos in the cutback adhesive. It would have to be skim coated with an encapsulant or be removed. Removal was not our choice, but I had concerns about the cutback bleeding through the vinyl plank over time. That reinforced the need for an encapsulant.
As mentioned before, carpet was installed after the vinyl asbestos tile was removed. I have no idea when that happened, but I know that the tack strip concrete nails left pockmarks in the concrete and through the cutback adhesive as well. These pockmarks had to be filled with a cementitious filler.
Cracking of concrete. The concrete was cracked about 20’ into the room, and ledged about 1/8”. In the crack there appeared to be alkaline salts, which meant in all likelihood there was moisture in the slab. So I set two moisture probes in compliance with ASTM F-2170 about 10’ on each side of the crack. I drilled down to about 1 3/4” as recommended by the manufacturer. I feel that the measurement at 40% of the slab thickness is much more accurate than the calcium chloride test, and the wait is much shorter. I awaited the allotted time for the probes to calibrate and give us a reading of either a plus or negative for moisture. The readings were 77% and 79% which meant that it was good to install the new flooring product. We vacuumed out the salts and any other debris so we could acquire a good bond.
Embossing leveling. The inlaid sheet vinyl featured a heavily embossed pattern, and the possibility of asbestos was likely because it was most probably the original floor installed in 1972, and all the white felt backing was asbestos until 1979. We decided that because it was well-bonded we would remove about an inch in a doorway that had curled and place an embossing leveler over the entire sheet vinyl area. Remember to work on a diagonal to the pattern.
Ardex embossing leveler and encapsulant. We needed a cementitious filler that would do all the tasks I needed at once, so I looked to Ardex for an embossing lever, an encapsulant, a crack filler and a hole filler. They had just the item, mixed with an additive for bond strength. The only downside was that it was slower to dry, but the benefits of using only one product more than made up for it.
The floor was ready for the new vinyl plank. We started in the living room because it was the longest and straightest wall. We determined how much we had to cut off, so we did not end up with a small piece along the wall somewhere. We ended up cutting 1 1/2” off the starting row to accomplish that.
We took into consideration the expansion zone required which is 1/4” around all permanent obstacles. We also decided on how to space the end joints, which we determined to be about one-third of the 4’ boards (16”). We worked three rows out of three cartons at a time, so we did not get too many of the same color planks in the same areas. The floor went in as nice as one could expect and in suitable time.
The installation has now been in close to a year, and it looks like a new floor should.