The world of tile allows for many specialties to emerge from the old-world kilns. The author looks at some of the methods used in the completion of a Mexican Saltillo Paver Tile installation.



Mexican pavers are so porous, it is almost impossible to grout them unless they are sealed with a penetrating or top-coating sealer of oil, wax, or grout release (photo 1 and 2). The tiles seen here are sealed with a single coat of penetrating oil prior to grouting; they will be given another coat after grouting has finished.

Various treatments involving oils, impregnators, colorants and waxes can be used with Mexican paver tiles, but they must be sealed before grouting. After grouting, it is good practice to add at least one more coat of sealer, since the grouting process is comparable to sanding and will remove much of the luster of the first coat. A finish layer could be a coating of paste wax or a liquid-applied material.

Grouting Mexican Paver Tiles

Because of the width of the joint required for Mexican paver tiles, and the varying nature of the color of the tiles, I normally use a natural cement-colored grout made with Portland cement, sand, and a latex additive. The preferred mix is one part Portland cement to two or three parts all-purpose sand. Finely graded sand, the kind used in regular-sanded grout, may cause some shrinkage in the wider joints. Coarse sand gives better results.

The powders and liquid are mixed together, allowed to slake for about ten minutes, remixed, and applied to the joints. Use the face of the trowel to compact the grout (photo 3), and the relatively sharp edge to remove excess grout from the face of the tile (photo 4).

Mexican pavers will require more work to grout than smooth floor tiles, but the procedure is about the same: compact the grout; allow it to set up firm; clean with a minimum of water; remove any lingering haze within an hour or two of grouting; and allow the grout to cure before applying any more sealer or wax. Too much water in the mix or during cleaning will result in soft, powdered, or cracked joints; use the least amount of liquid possible.

Timing is extremely important. If you attempt to begin cleaning the excess to soon, grout may be sponged out of the joints, leaving low spots that are unattractive and hard to clean. But if you wait too long, the grout may crust over on the tile surface and in the joints, making cleanup more difficult as well as allowing the grout to harden too much, which usually results in an uneven joint surface. On most installations, it is good practice to spread 15 to 20 square feet of grout, then test the firmness of the grout in the joints. If it is soft and plastic, allow more time for it to set up, spreading more grout while you wait. If it is firm, begin cleaning. Width and depth of the joint, plus temperature, humidity, and wind speed across the surface of the tiles, all help determine how quickly grout will set up.

Begin by spreading grout over one end of the floor and work toward the opposite end, holding the grout trowel at a low angle and packing the grout from several different directions so each joint is completely filled and flush with the surface of the tiles. As each section of the floor is grouted, hold the face of the trowel perpendicular to the surface of the tiles, and the edge of the trowel diagonally to the direction of the joints, scraping away the excess grout. Wide joints need extra time to setup, so it is important that as much excess as possible is removed. Any residue on the surface of the tiles will set up, harden, and require extra time and energy to remove.

Finishing

Final cleaning begins with a barely damp sponge and a bucket of clean water. Wring as much water as possible from the sponge, shake off any excess so that no water drips on the tiles, and gently scrub the surface of tiles until the grout residue is loosened (photo 5). Rinse the sponge frequently, as build-up on the sponge can rake grout out of the joints.

After the surface of the tiles is clean, turn to the grout in the joints, using the sponge to smooth and make them as uniform as possible. Give the tiles a final cleaning by slowly dragging the sponge across the surface, using a clean side of the sponge for each stroke (photo 6). This procedure continues until the entire floor is clean.

Once the grout is quite firm, and a faint grout haze has formed on the surface of the tiles, use the tip of a narrow tuck pointer to scrape out grout from the expansion joint slots (photo 7). The grout comes out rather crumbly and dry; remove it with the help of a vacuum. At the margins of the floor, use a tuck pointer or margin trowel to trim the edge of the grout surrounding the decorative spots. Any lingering haze is removed with a soft cloth. The grout is allowed to dry and harden undisturbed for 72 hours before the final coat of sealer is applied and the expansion joint is filled with flexible sealant.