Constant exposure to water and sedimentation or displacement of the walls of the bathroom can make grout around the tiles to crack. When this happens, it must be repaired to keep water away from the cracks. Over time, water may damage the structure and decompose the underlying layers. This will trigger costly repairs which could have been avoided by repairing the broken grout. This type of repair is a job that you can do yourself without hiring a professional.

Instructions

1. Cut the grout lines with a saw meant for that purpose. This is a hand tool that has a narrow diamond leaf. The blade is designed to fit inside the grout lines between the tiles. Move the saw back and forth as much as you can along the old grout.
2. Use an industrial vacuum to get up all the pieces and wet the tiles with a damp cloth.
3. Fill a 1-gallon (3.78 L) bucket with water to a depth of no more than 1 inch (2.54 cm). Pour the grout mixture into the bucket a little at a time. Mix the grout in the water with a 3 inches (7.62 cm) spatula. Continue adding the grout powder to the water until the mixture is slightly thicker than cake batter. The grout should be thick enough to stay on the spatula but thin enough that it can be spread.
4. Spread the grout between the tiles using the spatula. Do not cover larger than 3 by 3 feet (0.9 by 0.9 m) areas. Keep the leveling to 45 degrees and drag on the tiles. Collects excess grout with a spatula and place the surplus back into the bucket.
5. Fill a 5 gallon bucket (18.90 L) with hot water. Dip a sponge in water and wring it out. Hold the sponge flat on the tile, passing over the grout lines. Apply gentle pressure to the sponge and pass through the grout lines to soften. Move the sponge horizontally for horizontal grout lines and vertically for vertical grout lines.
6. Rinse the sponge often and repeat steps five and six for completion of the grouting.

Tips & Warnings

• If the grout is old and stained, replace the entire shower grout. Cut the grout lines with the saw deep enough so that it can contain all new grout.
• You can use a 4 1/2 inches (11.43 cm) grinder with a diamond carbide wheel to the extent that there is enough space between the tiles. If you use this method, be careful not to get too close to the tile as you can break it.
• Do not grout areas larger than 3 by 3 feet (0.9 by 0.9 m). The grout dries quickly and is extremely difficult to remove once it has dried.