Natural stone tile flooring.

Natural stone tiles are durable, natural tiles used as surface materials for floors, walls, and countertops, but they may still crack due to accidents or natural wear and tear. Fortunately for homeowners, these cracks, thick or hairline, may be remedied with the use of non-sanded caulk. Although using epoxy is also an option and may provide better results, its use is reserved to Phoenix Tile Cleaning & Sealing DIYer’s experienced in handling polymers.

Step 1 – Clean the Surface

Prepare the mild detergent solution by mixing water with detergent or dish washing liquid. Dip the sponge in the soapy water and clean the surface of the tiles that have cracks. Rinse with water. If your tiles are used in moist areas like the bathroom or kitchen sink, you have to clean it with oxygen bleach to remove molds, algae and other organisms that might be attached to the surface. Mix oxygen bleach with water in a 50:50 ratio and wipe it on the surface of the tiles. Rinse with water. For kitchen floors, apply degreaser on the tile to remove oil on the surface. Apply and rinse using the manufacturer’s instructions. Let the surface dry completely.

Step 2 – Prep the Crack and the Tile

Dry the surface thoroughly with the help of a hair blower if you plan to fill the crack immediately. You may skip this if you allowed the surface to dry overnight.

Strip the old sealer off the surface of the tile. Apply stripper on the surface with a paintbrush. Rub the surface with a cloth or scouring pad to mechanically shed off the old sealer. Prep the cracks next.

For hairline cracks, insert the single edge razor blade on the crack. Move the blade up and down, as though you are sawing the crack. Blow on the inside of the crack to remove debris and remaining dirt, or use a vacuum cleaner. Use a nail file for thicker and larger cracks. This is to create an even, yet rough surface for the caulk.

Step 3 – Fill the Crack 

Purchase a nonsanded caulk in a color that matches your tile and that comes with a gun. Prepare the caulk using the manufacturer’s instructions. If you are a novice Phoenix Tile Cleaning & Sealing DIYer, you may purchase a pre-mixed caulk.

Squeeze the caulk gun and fill the crack with caulk. Use a toothpick to push the compound into the bottom of the crack. Let the caulk overflow on the surface to allow the caulk to fill all the spaces. To scrape it off flat, get the one-sided razor blade again, and scrape the sharp edge perpendicular to the line of crack. Wipe the surrounding areas with a wet cloth or sponge to remove excess caulk. Let it dry overnight.

Step 4 – Apply Sealer

Apply sealer on the surface using a paintbrush. This is to protect the surface of the tiles, as well as the newly repaired cracks from moisture, oil and chemicals.