Monday, February 25, 2008

Tile a Picture Window Sill

Small two-inch tile turned out to be the perfect finish for our window sill. The window has a nine-inch space almost ten-feet long. The project is a viewing area of an indoor horse arena. We choose a small tile in order to enhance the colored grout line. While the brass railing helps prevent viewers from resting their dirty riding boots on the window sill, we wanted an easy to clean and durable surface.

We selected an near white tile with dark green grout. The light-colored tile accents the pine paneling and matched the painted white window trim. The dark green grout matches the wrought iron furniture.


  • Sponge float
  • Notched trowel
  • Sponge
  • Tile cutter
  • Tile snipper
  • Bucket
  • Work gloves


  • Ceramic tile
  • Grout
  • Mastic adhesive
  • Grout sealer

Level of Difficulty 2 out of 5
Time Required: 4 hours


The window still is two layers of 3/4" plywood with no measurable deflection. Normally cement backer board would be used, but the window will not be walked on. The wood surface should be clean and free of surface imperfections. Use a hand scraper or planner to ensure that the mastic will adhere to the clean surface.


With the surface scraped, vacuum the area and start the layout. First check the area to ensure that the sill is a uniform width. Next, run a string line to see how straight the sill is. It is best to identify any imperfections before trimming the tile. There is probably no need for a chalk line for this particular project.

We purchased tiles in one foot square lots with caulk tabs separating each tile. Depending on your experience level, you may wish to trim off the last row of tiles and cut these tiles separately. We choose to trim off the last row as there are several more cut outs required for the center window columns.

Cut the tile

The best way to cut tile is with a cutter. This unit (often can be rented where you purchase the tile) is used to score and break the tile in a straight line.

To fill pieces near the window column use a tile snip or Rotozip.

For a small project like this, it is best to cut and trim each tile to fit. Be sure to leave a grout gap of about 1/8" around the edges. Now carefully, remove all the tiles from the sill and set them aside.

Spread the adhesive

The adhesive, known as mastic, goes onto the window sill with the notched trowel. We used a small "V-notch" for the small 2" tiles. When applying the adhesive, use the flat edge to apply a layer of adhesive first. Next, hold the trowel at a 45 degree angle to the wall and "comb" the mastic out. With less than 10 square feet, one can probably cover the entire surface in one pass.

Placing the Tile

Start at the edge and work your way down the sill. When pushing the tile against the adhesive, use a slight twisting motion in order to set the tile firmly in the adhesive. If you are using spacers, now is the time to set the spacers on the outside edge of the tile in order to work on the next row of tiles.

After all of the tiles have been placed and the adhesive has setup a bit, clean the adhesive from between the tiles and from their faces. A toothpick is a great tool for this. Allow the adhesive to setup overnight before grouting the tile

Grouting the Tile

After the tile adhesive has had time to dry (usually overnight), it is time to grout the tile. Grout is also available pre-mixed or dry. For the dark green grout, we purchased dry mix. It is easy to blend, just follow the instructions. It should be fairly thick, but not so thick that you can't force it into the joints (gaps).

After the grout is ready to go, take your foam rubber float or other appropriate implement and scoop some grout out. Place the grout on the wall and holding the rubber float at a 45 degree angle to the work piece run the float parallel to the joints in the tile. Round up the excess grout and run the float over the surface several times in order to fill in the joints. When the gaps are full, run the float over the surface at a 45 degree angle to the joints. Run the float over the surface several times until most of the grout is either in the joints or on the trowel.

Cleaning Excess Grout

Allow the tile to set up for 15-30 minutes, or until firm, in the joints. Using a damp sponge or cloth wipe any excess from the face of the tiles. Rinse out the sponge or rag often enough to keep it clean.

Allow the grout to dry another 45 minutes or until a haze forms on the tiles and use the sponge to polish the surface of the tiles. Be careful not to rub the grout from the joints. If it seems like you just can't get the tile clean then let it dry a bit more. After several hours you should use a clean towel to polish the tiles.

Curing the Grout

For the next three days, before using a grout sealer, lightly mist the grout. On the fourth day, use a grout sealer to ensure a good solid installation. These sealers will keep the grout sealed from stains and water.

1 comment:

new_tangled said...

Great little artical, thanks very much