How to Re-Grout a Shower Yourself (Step-by-Step Melbourne Guide)

Skill Level: Handyperson | Time: Half day (plus 24h drying) | Cost: $60–$150 materials

What You’ll Need

Step-by-Step: How to Re-Grout a Shower

Step 1: Assess the Grout and Plan the Job

Before buying materials, inspect every joint in the shower. Look for: cracked or crumbling grout, black mould that won’t clean off, missing grout sections, grout pulling away from the tiles, and any movement between tiles. Pay particular attention to the floor-to-wall corners and the junction between the shower walls and the floor — these should be silicone, not grout. If any tiles are loose or hollow-sounding when tapped, stop — you may have a waterproofing membrane failure underneath that needs a licensed tiler to assess before you re-grout over it.

Step 2: Remove All Old Grout

Fit an oscillating multi-tool with a carbide-tipped grout removal blade. Run the blade along each joint, keeping it centred to avoid scratching the tile edges. Aim to remove at least 3–4mm depth of grout to give the new grout enough key to bond properly. Work systematically — top rows down, left to right. Vacuum out all loose grout dust before moving on. This step creates significant dust; open windows, wear a P2 dust mask, and protect bathroom surfaces with drop sheets.

Step 3: Prepare the Surface

After removing old grout, vacuum all joints thoroughly, then wipe down the entire shower with a damp cloth. Check each joint with a torch — the base should be clean, dry, and free of grout fragments. Any black mould remaining in the joints can be treated with a diluted bleach solution (1 part bleach to 4 parts water) applied with an old toothbrush. Allow to dry completely — at least 4 hours — before grouting. Tile surfaces must be completely dry for new grout to bond correctly.

Step 4: Mix and Apply the Grout

Mix the grout with clean water following the manufacturer’s ratio — typically 3 parts grout powder to 1 part water. Mix to a smooth, thick peanut butter consistency using a margin trowel or mixing stick. Let it rest (slake) for 5 minutes, then briefly remix. Load your rubber grout float and push the grout diagonally across the joints, working in sections of about 1 square metre at a time. Push grout firmly into each joint and work at a 45-degree angle to the tile joints to prevent the float from dragging grout back out.

Step 5: Clean Off the Excess and Shape Joints

Wait 15–25 minutes after grouting (depending on temperature — faster in warm Melbourne spring weather, slower in winter). The grout should feel firm but not rock hard. Wipe diagonally across the tiles with a damp, well-wrung-out sponge. Rinse the sponge frequently in clean water — dirty water redeposits grout haze. Use a damp fingertip to shape a slightly concave surface on each joint. A second pass with a cleaner sponge after another 20 minutes removes most of the remaining grout haze. For stubborn haze after full curing, use grout haze remover on a soft cloth.

Step 6: Apply Silicone to Corners and Floor Junctions

The corners of the shower (wall-to-wall, wall-to-floor) must never be grouted — they must be silicone. Grout cracks at these movement joints because the walls and floor flex independently. Remove any old silicone with a Stanley knife and silicone remover solvent. Mask both sides of the corner with painters tape, apply mould-resistant silicone from the tube, and smooth with a wet finger or silicone finishing tool. Remove the tape before the silicone skins over (within 5–10 minutes).

Step 7: Seal the Grout

After 24 hours (48 hours in cool, humid Melbourne winter conditions), apply penetrating grout sealer to all tile joints using an applicator bottle or small brush. The sealer soaks into the porous grout surface and dramatically reduces water and mould penetration. Apply two coats, 30 minutes apart. Wipe off any sealer that lands on tile faces before it dries. Do not use the shower for at least 24 hours after sealing.

Troubleshooting Common Shower Re-Grouting Problems

When to Call a Professional Tiler

Re-grouting is a genuine DIY task for most Melbourne homeowners, but stop and call a licensed tiler if you find: loose or hollow tiles (tap them gently — a hollow “clunk” means debonding), tiles that flex when pressed, visible moisture staining on the wall behind tiles, grout failure that keeps recurring in the same spots, or any sign that water has been getting under the tiles. These are symptoms of waterproofing membrane failure — a problem that requires licensed waterproofing work under the Victorian Building Authority’s standards. Re-grouting over a failed waterproofing membrane will not stop water damage — it only delays a far more expensive repair.

Top 10 Shower Re-Grouting Tips and Gotchas

1. Hire the oscillating multi-tool. This is non-negotiable. Hand scrapers take 10x longer and create a jagged joint that new grout can’t fill neatly.
2. Don’t scrimp on grout removal depth. Remove at least 3–4mm for proper adhesion. Skimming over existing grout almost always fails within a year.
3. Use epoxy grout for the floor. Floor grout gets the heaviest traffic and water. Epoxy grout ($60–$120 for a kit) is far more stain and mould resistant than standard cement grout.
4. Match the colour when buying. Take a photo of your existing grout to a tile specialty store or Beaumont Tiles. Grout looks different dry vs wet — always check the dry sample card.
5. Seal it or redo it in 2 years. Unsealed cement grout in a Melbourne shower typically turns black within 6–18 months. Sealing adds one extra step but extends the life of the job by years.
6. Silicone at every corner, grout on flat runs only. The single most common re-grouting mistake is grouting the wall-to-floor corner. It will crack. Always silicone these movement joints.
7. Keep the sponge clean. Rinsing in dirty water redeposits grout haze on tiles. Use two buckets — one for rinsing the sponge, one with clean water to wash the sponge out.
8. Temperature affects drying time. In Melbourne’s winter (under 15°C), grout takes longer to cure — wait 48 hours before sealing and before using the shower.
9. Ventilate the shower after every use, forever. The best re-grout job fails fast in a poorly ventilated bathroom. Run the exhaust fan for 15–20 minutes after every shower.
10. Check for hollow tiles before you start. Tap every tile before starting work. Hollow tiles mean the tile adhesive has failed — fixing this before re-grouting saves you from having to redo the entire job later.

Local Melbourne Resources

• Bunnings Grout and Tile Products — Standard cement grout, silicone, and sealer
• Beaumont Tiles Melbourne — Epoxy grout, colour matching, and tile specialty advice
• Total Tools — Oscillating multi-tools and grout removal blades for hire or purchase
• Mitre 10 — Silicone sealant, grout floats, and tile cleaning products
• Victorian Building Authority — Licensed tiler search for waterproofing and full retiling jobs

Frequently Asked Questions