Old grout looks grim - cracked, stained, mouldy. The good news? Regrouting is one of the most satisfying bathroom improvements you can do. Takes a day, costs under £30, and the results are dramatic.
When to Regrout
Signs it's time:
- Grout is cracked or crumbling
- Mould you can't clean off
- Grout is discoloured beyond cleaning
- Gaps appearing between tiles
- Water getting behind tiles
Important: If tiles are loose, fix that first. Regrouting won't solve loose tile problems.
What You'll Need
Tools:
- Grout rake or oscillating multi-tool with grout blade
- Grout float (rubber squeegee for applying grout)
- Sponge
- Bucket
- Spray bottle
- Old toothbrush (for corners)
- Safety glasses (bits fly when removing old grout)
Materials:
- Grout (see below for type)
- Grout sealer (optional but recommended)
- Masking tape (optional, for edges)
Cost: About £20-£30 for a standard bathroom
Choosing the Right Grout
Cement-Based Grout
The standard choice. Comes as powder you mix with water.
- Sanded: For gaps wider than 3mm
- Unsanded: For gaps under 3mm (better finish)
Brands: BAL, Mapei, Dunlop. They're all fine for bathrooms.
Epoxy Grout
Premium option. Completely waterproof and stain-resistant.
- Harder to apply
- More expensive
- Lasts longer
- Doesn't need sealing
Good for showers and wet rooms where water resistance really matters.
Grout Colour
White: Classic but shows dirt quickly Grey: Hides dirt better, very popular now Dark colours: Modern look, very forgiving for maintenance
Step 1: Remove Old Grout
This is the hardest part - there's no shortcut.
Manual method (grout rake):
- Run the grout rake along each grout line
- Apply pressure and repeat until you've removed 2-3mm depth
- Brush out debris
- Hoover the dust
Power tool method (faster):
An oscillating multi-tool with a grout blade makes this much quicker. Just don't slip onto the tiles.
How much to remove?
Aim for at least 2mm depth. You're creating a key for new grout to bond to. If old grout is really crumbly, go deeper.
Warning: Don't damage the tiles. Take your time at corners and edges.
Step 2: Clean the Joints
After removing old grout:
- Hoover out all debris
- Spray with water
- Wipe with a damp sponge
- Let dry (or at least let excess water drain)
The joints need to be clean but slightly damp for best adhesion.
Step 3: Mix the Grout
If using powder grout:
- Add water to powder gradually (not powder to water)
- Mix to thick paste consistency - like peanut butter
- Let it slake (rest) for 5 minutes
- Mix again
Too wet: Grout will shrink and crack Too dry: Hard to work and won't bond properly
Only mix what you'll use in 20-30 minutes.
Step 4: Apply the Grout
Technique matters here:
- Load grout onto your float
- Hold float at 45-degree angle to tiles
- Push grout firmly into joints - work diagonally across tiles
- Scrape off excess with float held at 90 degrees
- Work in small sections (about 1 square metre)
Key points:
- Push hard - grout needs to fill the joint completely
- Work diagonally so you don't dig out what you just filled
- Don't leave it too long before cleaning (10-15 minutes max)
Step 5: Clean Off Excess
This is where most people mess up.
First wipe (10-15 minutes after applying):
- Use a damp (not wet) sponge
- Wipe diagonally across tiles
- Rinse sponge frequently
- Don't dig into the joints
Second wipe (30 minutes later):
- Clean any remaining haze
- Use a nearly dry sponge
Final polish (when completely dry):
- Buff with a dry cloth to remove haze
Common mistake: Using too much water. This washes grout out of the joints. Wring your sponge properly.
Step 6: Seal the Grout (Optional but Recommended)
Once grout is fully cured (24-48 hours), apply a grout sealer.
Why seal:
- Prevents water absorption
- Stops staining
- Makes cleaning easier
- Extends grout life
How:
- Apply with small brush or sponge
- Wipe off excess from tiles
- Let dry
- Reapply annually
Epoxy grout doesn't need sealing.
Grouting Around Bath and Shower
Where tiles meet the bath, shower tray, or sanitary ware - don't use grout. Use silicone sealant.
Why? These joints move slightly. Grout will crack. Silicone stays flexible.
Troubleshooting
Grout cracking:
- Probably mixed too wet
- Or joint wasn't filled completely
- Remove and redo
Colour uneven:
- Different amounts of water in different batches
- Or cleaned some sections too wet
Haze won't come off:
- Use a proprietary grout haze remover
- Or very light acid solution (vinegar and water)
Mould appearing:
- Ventilation problem
- Consider epoxy grout next time
- Or apply antimicrobial sealer
How Long Does It Take?
For a standard bathroom (around 10-15 square metres of tiles):
| Stage | Time |
|---|---|
| Remove old grout | 2-4 hours |
| Clean and prep | 30 minutes |
| Apply new grout | 1-2 hours |
| Clean up | 30 minutes |
Total: One solid day's work
Should You DIY or Hire?
DIY if:
- You're patient and methodical
- The bathroom isn't huge
- It's cement grout (not epoxy)
Hire if:
- Large area to do
- Epoxy grout needed
- You want a perfect finish
- Your time is worth more than the cost
Rather have someone else do it? I regrout bathrooms across Exeter - usually in a day. Call 01392 964094 or get a quote.
Sam Hembury
Sam is the founder of Hembury Contracting, providing professional handyman services across Exeter and Devon. With years of experience in property maintenance, he shares practical tips to help homeowners tackle common tasks.