How to Regrout Shower Tile (Step-by-Step Guide for Walls and Floor)

Shower tile grout takes more abuse than almost any other surface in your home — constant moisture, soap residue, temperature changes, and daily scrubbing all wear it down over time. When shower grout starts cracking, crumbling, or growing mold that won't go away, regrouting is the most effective long-term fix.

This guide walks you through how to regrout shower tile on both walls and the floor, with tips specific to wet area applications.

Signs Your Shower Grout Needs Replacing

• Grout is cracking or crumbling in multiple places
• Black mold keeps returning despite cleaning
• Grout has turned permanently grey or brown and won't clean up
• Water is getting behind the tiles (soft wall behind tiles, musty smell)
• Grout is more than 10 years old in a heavily used shower

What You'll Need

• Grout Removal Tool — to remove all old grout
• Pre-Mixed Tile Grout — use a mold-resistant formula for showers
• Grout Float
• RMR-86 Mold Remover — to treat any mold before regrouting
• Damp sponge and bucket of clean water
• Grout sealer rated for wet areas
• Silicone caulk (for corners and transitions)
• Safety glasses and gloves

How to Regrout Shower Tile: Step-by-Step

Step 1: Stop using the shower for at least 24 hours.
The shower must be completely dry before you start. Moisture in the joints will prevent new grout from bonding properly.

Step 2: Remove all old grout.
Use a grout removal tool to rake out all old grout from every joint — walls and floor. For shower walls, work carefully to avoid gouging the tile edges. Remove grout to a depth of at least 2–3mm.

Step 3: Treat any mold.
With the grout removed, inspect the joints and tile edges for mold. Spray RMR-86 Mold Remover on any affected areas, allow to sit for 5 minutes, then wipe clean. Allow to dry completely before proceeding.

Step 4: Vacuum and clean all joints.
Vacuum out all dust and debris. Wipe with a barely damp cloth and allow to dry fully — at least a few hours, or overnight for best results.

Step 5: Apply new grout to walls first.
Start with the shower walls before the floor. Load your grout float and press grout firmly into the joints at a 45-degree angle. Work in small sections. Wipe excess off the tile surface with a damp sponge before it sets.

Step 6: Grout the shower floor.
Once the walls are done, move to the floor. Apply grout the same way — pressing firmly into joints and wiping excess promptly.

Step 7: Use caulk in corners and transitions.
Do not grout the corners where the wall meets the floor, or where two walls meet. These areas experience movement and grout will always crack there. Use waterproof silicone caulk instead — it stays flexible and creates a watertight seal.

Step 8: Allow to cure.
Do not use the shower for at least 48–72 hours after grouting. Grout in wet areas needs longer to cure than in dry areas.

Step 9: Seal the grout.
Once fully cured, apply a grout sealer rated for wet areas. This is non-negotiable in a shower — unsealed grout in a shower will absorb water and develop mold within months.

Shower-Specific Tips

• Choose a mold-resistant grout formulated for wet areas — it contains additives that inhibit mold growth
• Use unsanded grout for joints under 1/8 inch, sanded grout for wider joints
• Always caulk corners — never grout them in a shower
• Reseal shower grout every 6–12 months for maximum protection
• Run the exhaust fan during and after every shower to reduce moisture buildup

Frequently Asked Questions

How long does shower regrouting take?
Plan for 2–3 days total: one day for grout removal and drying, one day for applying new grout, and one day of cure time before use.

Can I regrout a shower without removing tiles?
Yes — regrouting only removes and replaces the grout, not the tiles. As long as the tiles are in good condition and firmly bonded, you don't need to remove them.

What grout is best for showers?
Epoxy grout is the most durable and mold-resistant option for showers. Pre-mixed cement grout with a mold-resistant formula is a good middle-ground option that's easier to work with.

How often should shower grout be replaced?
With proper sealing and maintenance, shower grout can last 8–15 years. In heavily used showers, inspect annually and plan to regrout when you see widespread cracking or persistent mold.