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Laying A Stone Floor

- Continued

Mud Time

The mason mixed a rich, thick mortar of one part cement to two parts sand, plus an acrylic fortifier. Because of the uneven thickness of the slabs, he worked one stone at a time, leveling from our reference marks and from adjacent stones (Figure 6). He used a pointing trowel called a slicker to press the mortar down tight between stones and to remove any excess mortar. We finished this stage by sponging the stones clean

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Figure 6. The mason was responsible for cutting in around passages and other obstructions (left). Because the stone was of varying thickness, each piece had to be carefully leveled in reference to the finish floor height (right).

Sealer

We waited several days before sealing the stone, and as it fully dried, we could see that quite a bit of cement residue and dirt remained on the stones. In the meantime, we researched and tested various sealants and finally settled on a solvent-based sealer with a color-enhancing matte-finish top coat (Figure 7). We used two coats of Miracle Sealants' 511 Porous Plus (800/350-1901; ) and one coat of their Mira Matte. Before sealing, we also used their recommended cleaner, Grout and Concrete Film Remover, to clean the stone, which we had to do twice.

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Figure 7. After cleaning the stone with a proprietary cleaner, workers applied two coats of solvent-based sealer and one top coat to finish the job.

After cleaning, we waited two days and then applied the first coat of sealant. That was a bit tricky because the sealant has the consistency of paint thinner, and since the stones were not yet grouted for the first coat, we had to keep the sealer from running onto the edges of the stone. We used foam paintbrushes and painted the floor stone by stone, wiping up excess sealer after ten minutes of drying time. This was a slow process and required patience on the part of my crew, as well as good ventilation, rubber gloves, eye protection, and kneepads.

Grout

The following day, the mason grouted the stone, carefully squeezing the grout into place from a grout bag and using the slicker to tool the joint. After sponge cleaning, we waited another day before sealing both the stone and the grout. We let everything dry overnight and then applied the Mira Matte finish coat, which brought out the color of the stone without making it shiny. The finished floor was beautiful, but we still had all the wall finishes and trim to install. To protect the floors, we rolled out kraft paper, then put down a layer of 1/2-inch drywall. This makes a wonderful protective cover because it absorbs bumps and dings, has enough mass to stay in place, and can be swept off.

Cost

The cost of the 460-square-foot floor came out around $30 per square foot, not including supervision, broken down as follows:

8 tons of stone plus delivery, $4,225; 500 pounds of grout, $170; cleaner, sealer, and finish, $445; labor for sorting and cutting, 132 hours; dry-fitting, cleaning, sealing, 56 hours; mason's setting labor, $5,000.