Tiling a countertop

Installing a ceramic-tile countertop creates a beautiful, long-lasting, and functional work surface. Like floor tile, countertop tile is permanently installed using mortar adhesive and grout. Most tiles are countertop material—glazed, quarry, mosaic, or even stone tiles, such as slate or granite. You have your choice of many sizes and shapes of tile, but be aware that different sizes affect the finished appearance. Smaller tiles require more grout lines that may stain or degrade with use. Larger tiles are more appropriate for floors. Midsize tiles (4 to 6 inches) are ideal for countertops.

The surface below the countertop tile may be more important than the surface beneath a tiled floor. Carefully follow the steps involved in preparing the substrate (the surface below the tile) to avoid problems.


• Mortar is a mixture of sand and Portland cement.

• Dry-set mortar is a specially formulated mixture for application over backerboard.

• Latex Portland cement mortar has a latex additive that makes the mortar more flexible, and is best suited for countertops. You’lt find two types—one is a powder to which a liquid latex additive is added; the other is a powder containing dry latex resin to which water is added. Both do the job equally well.

• Backerboard is a rigid panel that provides a sound substrate for setting tile. Depending on the manufacturer, backerboard can be made of cement, fiber cement, gypsum, plywood, or plastic. Fiber cement panels do not require fiberglass mesh to bind the material into a panel. Although several thicknesses are available, 1/4 and 1/2 inch are commonly used for both walls and floors in residential construction. Follow the manufacturer's recommendations for installation.

MATERIALS: Ceramic tiles, edge tiles or edge bead, mortar, grout, grout sealer, scrap 2x4, 3/4 inch exterior-grade plywood, 4-mil plastic sheeting, backerboard, backerboard screws, 1 1/4-inch drywall screws, 3-inch fiberglass tape, tile spacers

TOOLS: Drill with 1/8 inch masonry bit and Phillips bit, tape measure, utility knife, notched trowel, drywall tape knife, tile cutter or wet saw, tile nippers, level, rubber grout float, burlap

A BALANCED APPROACH - The tiles around your sink look best when they are the same width on all sides. The time to solve this problem is while you're laying them out. On a straight counter, lay out the tiles so that the first one is centered over what will be the center of the sink and work toward the ends. If the counter is L-shape, however, lay out the tiles with a full tile in the corner. If placing the tile there creates problems at the sink, reposition the sink opening before you cut it to make sure you have equal widths all around the sides.

1 INSTALL A PLYWOOD SUBSTRATE. The base cabinets form the structural support for the countertop. Install 3/4 inch exterior-grade plywood cut to fit. Screw it in place with 1 1/4-inch drywall screws, shimming as necessary to ensure a flat surface.

2 CUT OUT PLYWOOD FOR THE SINK. New sinks often come with a template or measurements. (If you are reusing the old sink, measure the opening after you remove it.) Position the template. Make sure the new faucet will clear the wall behind the counter. Mark the cutout. Drill a 3/8 inch starter hole inside the cutout near one of the corners; then cut with a saber saw.

3 INSTALL BACKERBOARD. Cut it to fit by scoring and snapping. Cut sink curves freehand on both faces. Finish curves by snapping material away with pliers. Leave a 1/8-inch gap between pieces for mortar. Predrill screw holes every 6 to 8 inches. Remove the pieces and staple on a 4-mil plastic moisture barrier. Apply mortar on the plastic with a 1/4-inch notch trowel. Reposition the pieces and install them with backerboard screws.

4 TAPE AND FILL SEAMS. Reinforce exposed edges of the backerboard with three layers of fiberglass tape. Then apply a 3-inch-wide layer of latex Portland cement mortar to fill the gaps between sheets of backerboard. Lay a strip of fiberglass mesh tape across the gap. Press the tape firmly into the mortar with a 4-inch taping knife.

5 APPLY AN EDGE BEAD. Apply a stainless steel decorative edge by bending it around the corners and nailing it into the backboard with galvanized nails. An alternative is to use ceramic edge trim for a softer look.

6 CUT THE TILES TO SIZE. Use either a score-and-snap-type tile cutter or a wet saw to make straight cuts in the tile. Mark the tile with a felt-tip pen and position it against the fence on the tile cutter. Hold the tile firmly and slide the scoring wheel across the tile in a continuous motion. Reposition the tool with the pressure plate flat against the face of the tile and press down to snap the tile.

HELPING HAND - Cutting tiles is fairly simple, but if you’re uncomfortable about it (or just don't want to spend money on the one-time use of a tool), mark all the tiles that need to be cut and take them to a tile supply company or a home center with a reputable tile department. They usually employ a tile cutter, who will make the cuts for a fee. Mark the tiles carefully with their locations in the layout.

7  DRY-FIT THE TILES. Tiles vary widely from the size they're supposed to be. To avoid surprises, lay out the entire countertop before applying mortar. Lay all the full tiles first, then cut the others to fit. In countertops with a sink, adjust the layout to ensure the tiles are even on each side of the sink. On an L-shape countertop, start with a full tile at the inside corner. Use tile spacers to maintain even spacing. Leave a 1/8-inch gap between perimeter tiles and the wall.

8 CUT THE TILES AROUND THE SINK. Cutting curves or notches is more challenging than straight cuts.  Mark the cut with a felt-tip pen. Gradually nip off small pieces of tile with tile nippers to reach the mark. Sand or smooth with a file if necessary.

9 SPREAD THE MORTAR. Mix the mortar according to the label directions. Spread an even coat of mortar with a notched trowel. The mortar instructions will specify the appropriate notch size, which is determined by the size of the tile. Hold the trowel at a consistent angle (about 45 degrees) and drag it against the backerboard surface.

10 LAY THE TILES IN THE MORTAR. Start laying the full tiles at the more critical areas of the layout—around the sink or at an inside corner of an L-shape counter. Work from front to back, placing as many of the full tiles as possible. Press each tile into the mortar with a slight twisting motion. Use tile spacers to keep the tiles aligned. To level the set tiles, place a straight piece of 2x4 on its edge across the tile, then tap gently on it. Check for flatness with a 2-foot level.

11 LAY PARTIAL TILES AT THE PERIMETER AND AROUND THE SINK. When all the full tiles are in place, set the partial tiles and any tiles cut to fit around the sink. Use the spacers between cut tiles and full tiles. Let discrepancies in spacing end at the wall—the backsplash or trim will hide any flaws.

TILING THE BACKSPLASH - The section of wall against the countertop covered with countertop material is called a backsplash because it protects the wall from splashes, bumps, and spills. You can make the backsplash a few inches high, or run it to the cabinets above, as shown at right. Whatever method you use, put up backerboard before you tile. Follow the same procedure as for the countertop: Put mortar directly on the wall, put backerboard over it, and screw it to the studs. Leave spaces between the edges, fill with mortar, and cover with fiberglass tape.

12 TILE THE BACKSPLASH, running the tiles from the counter to the bottom of the wall cabinets, or stopping after a single row. If you're only applying a single row, use bullnose tile, which has a finished edge. If the backsplash wall contains electrical outlets, cut tiles around them and add box extension rings (available in the electrical department) to bring the outlets flush with the tiles.

13 TILE THE EDGE. If using edge bead, cut the tiles so that they bridge the grout lines on the main countertop, as shown. Apply grout. Put the tiles tightly against the bead and tape them in place to hold them while the mortar dries. If using edge tiles, it's unnecessary to tape them because part of the tile sits on the countertop. Space edge tiles so the grout lines between them match those on the counter.

14 GROUT THE TILE. After the tile has completely set [check the mortar instructions), pull out the spacers and apply the grout. Mix the grout following the manufacturer's directions. Spread grout across the counter with a rubber grout float. Work the grout into the joints by moving the float diagonally across the tile. Once all the joints are filled, remove excess by wiping diagonally with a wet sponge . Rinse the sponge frequently in clean water. Sponge off the excess grout from the surface of the tile and leave the grout slightly depressed in the joints. Let the grout dry, then rub the tiles with cheesecloth to remove the haze left by the grout.

15 SEAL THE GROUT. Because grout is prone to staining, seal it with a silicone grout sealer after it has cured completely—about 30 days, or as recommended by the manufacturer. Apply the silicone grout sealer to the grout lines with a foam brush or applicator, let it soak in for a few minutes, and wipe away the excess.

TILING OVER PLASTIC LAMINATE - You can lay tile over a plastic laminate countertop as long as there are no loose areas, and as long as the edges are square. (Rounded-over edges, or ’'waterfalls," between the backsplash and counters can't be tiled.) Edges that have lifted should be glued down with construction adhesive and clamps. Then screw down cement backerboard and follow the steps on these pages. Tiling over an existing countertop will make counter edges thicker and may affect sink and faucet installation.

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