How to Repair Cracking Grout in the Shower

Grout is the cement-like substance that fills in the spaces between your shower tiles. If it starts to crack and crumble, it means either that it wasn't properly installed in the first place, or that moisture or mildew has gotten into it. Cracked grout in a shower should be extracted and replaced immediately because it can become a pathway for water to seep into the wall behind the tiles, growing more mildew and causing loose tiles. Plan on being without use of the shower for a few days.

Things You'll Need

• Grout saw (straight carbide blade on a handle)
• Vacuum with hose attachment
• Grout
• Grout float
• Sponge
• Grout sealant
• Small paintbrush

Instructions

1. Dig out the damaged grout with your grout saw by running the saw forward and back over the grout line, breaking up the surface and gradually working your way down. Extract the grout from the full length of any tile where it's damaged at any point (so you're not re-grouting half a length of tile). Make sure not to scratch the tiles.

2. Use your vacuum hose to clean up any dust or debris out of the lines.

3. Scoop up some of your grout with your grout float (it's a flat rubber trowel), and press it directly into the open lines. Run the edge of the float over the area at an angle to squeeze the excess grout off the surface.

4. Let the grout sit in the lines for a minute, then wipe down the surface with a damp sponge. Wipe it gently, just enough to take up the excess grout from the surface without digging it out of the lines.

5. Let the grout set for at least two days. (Don't use the shower during this time.) Apply grout sealer on the new lines with the tip of a small paint brush.

Tips & Warnings

• Wear eye protection when digging out your old grout.

References

• HouseTask.com: Regrouting.