How to Regrout Wall Tiles – DIY Guide
How to Regrout Wall Tiles
Refresh tired, cracked, or discoloured grout lines and make wall tiles look new again.
To regrout wall tiles, rake out the old grout, clean the joints, then work fresh grout into the lines using a rubber float. Wipe off the excess before it sets and polish the tiles once dry. Most bathrooms take 2–3 hours to regrout.
- Grout rake or oscillating multi-tool with grout blade
- Rubber grout float
- Bucket
- Sponge
- Soft cloth or microfibre cloth
- Screwdriver or pointed tool for cleaning corners
- Safety glasses
- Dust mask
- Unsanded or sanded wall tile grout
- Grout cleaner or sugar soap
- Masking tape
- Clean water
- Grout sealer (optional, for porous grout)
- Tile trim or silicone sealant (for movement joints at edges)
Step-by-Step Guide
Rake Out the Old Grout
Use a grout rake or oscillating multi-tool fitted with a grout removal blade to dig out the existing grout to a depth of at least 2–3 mm — shallow removal leaves too little room for the new grout to bond and it will crack out again within weeks. Work along each joint at a steady pace and keep the tool square to avoid chipping tile edges. Wear safety glasses throughout; old grout produces fine, sharp dust. If you notice any signs of damp on the wall behind, address the cause before regrouting.
Clean and Prepare the Joints
Vacuum out all loose dust and debris from the joints, then wipe the tile faces and open grout lines with a damp sponge wrung almost dry. Mix a small amount of grout cleaner or sugar soap solution and scrub any mould or soap scum from the tile surface — grout will not bond to a greasy or contaminated joint. Allow the wall to dry completely before you proceed; in a bathroom with poor ventilation, this can take 30–60 minutes.
Mix the Grout to the Right Consistency
Pour the correct amount of clean water into a clean bucket first, then add the grout powder gradually and mix to a smooth, lump-free paste roughly the consistency of thick peanut butter. Follow the manufacturer’s water-to-powder ratio precisely — too much water weakens the final joint and causes shrinkage. Let the mix stand for two minutes, stir once more, then work within the open time stated on the bag (typically 30–45 minutes for standard wall grout).
Apply Grout Across the Tiles
Load the rubber float with grout and spread it diagonally across the tile surface, pressing firmly into the joints at a 45-degree angle to pack each line fully. Work in manageable sections of around one square metre at a time. Diagonal strokes prevent the float edge from digging into and pulling grout back out of the joints as you move across the wall. For joints around bath edges or where tiles meet different surfaces, use silicone sealant rather than grout — these are movement joints and rigid grout will crack. See our guide to tiling a bathroom wall for full guidance on which joints to seal.
Clean Off the Excess Grout
Wait 10–15 minutes after applying each section — the grout should start to firm up but remain slightly soft. Dampen a sponge and wring it out thoroughly, then wipe across the tile faces in a circular motion to remove surface grout. Rinse the sponge frequently and use as little water as possible; excess water dragged into the joints weakens them. Repeat this cleaning pass two or three times until the tile faces are clear. A thin grout haze will remain — this is normal. If you need to replace a broken tile in the same area, do that before regrouting the whole wall.
Polish the Tiles and Seal the Grout
Once the grout has fully cured — typically 24 hours, though check the bag — buff away any remaining haze with a dry microfibre cloth using firm circular movements. If you are using a porous, cement-based grout in a wet area such as a shower enclosure, apply a grout sealer with a small brush along each joint to protect against moisture ingress and staining. Keep the area dry and unsprayed for at least 24 hours after finishing. For guidance on tackling any broader wall repair work around your tiles, see our blown plaster guide.
Frequently Asked Questions
Can I apply new grout over old grout without raking it out?
No. New grout applied over existing grout has no mechanical key and will crack or peel away quickly. You must rake out the old grout to a minimum depth of 2–3 mm before applying fresh material.
What type of grout should I use for wall tiles?
For standard wall tiles with joints up to 3 mm wide, use an unsanded wall tile grout. For wider joints or floor tiles, use a sanded grout. In wet areas, choose a grout labelled as water-resistant or use an epoxy grout for maximum durability.
How do I remove black mould from grout before regrouting?
How long should I leave new grout before using the shower or bath?
Allow at least 24 hours before exposing fresh grout to water, and 48–72 hours for full cure in a heavily used shower. Check the specific cure time on your grout packaging as it varies between products.
Do I need to seal grout after regrouting wall tiles?
It is not always essential, but applying a grout sealer to cement-based grout in wet areas — particularly shower enclosures — significantly extends its life and prevents staining. Epoxy grout is non-porous and does not require sealing. Our Walls & Plastering Guide covers related maintenance tasks in the same area.
Before loading the float, dampen the tile face very lightly with a barely wet sponge — this slows the surface absorption of the grout and buys you a longer working time for cleaning, particularly in warm rooms. Don’t wet the open joints themselves, only the tile glazing.
Sources
- HSE — Working with cement and grout: skin and respiratory risks — hse.gov.uk
- Which? — How to regrout tiles — which.co.uk
- RIBA — Guidance on movement joints in tiling — architecture.com
This guide is for general information only. Always work safely and follow manufacturer instructions. DIYnut accepts no liability for injury or damage arising from DIY work.
