How to Regrout Tiles
Tired, discoloured grout makes even good tiles look bad. Regrouting is one of the cheapest bathroom refreshes you can do.
Difficulty
Easy
Time
3-5 hours
Cost
15-40
Safety First
Wear safety goggles when removing old grout as small pieces can fly off. Use a dust mask if using a power tool. Keep fingers clear of the grout rake blade. If working in a bathroom, ensure good ventilation when using grout sealer.
Regrouting is one of the most satisfying DIY jobs. It takes a bathroom or kitchen from grimy to gleaming in an afternoon. Old grout absorbs moisture, harbours mould and looks terrible. Fresh grout transforms the space. You do not need to remove tiles. You just remove the old grout from between them and apply new. The whole job costs under 40 in materials and takes a few hours.
What You Will Need
Tools
- - Grout rake or grout removal tool
- - Grout float (rubber)
- - Sponge (large, damp)
- - Bucket of clean water
- - Old toothbrush or detail brush
- - Dry lint-free cloth
- - Masking tape (optional)
Materials
- - Tile grout (premixed or powder)
- - Grout sealer
- - Silicone sealant (for corners and edges)
- - Silicone removal tool (if replacing sealant too)
Step-by-Step Instructions
Remove the old grout
Use a grout rake to scrape out the old grout from between the tiles. Work carefully so you do not chip the tile edges. You need to remove at least 2-3mm depth. For large areas, an oscillating multi-tool with a grout blade speeds things up enormously. Vacuum out all the dust and debris.
Clean the joints
Wipe down all the joints with a damp sponge to remove dust. Let the tiles dry completely. Any remaining dust will stop the new grout adhering properly.
Mix the grout
If using powder grout, mix it in a bucket according to the packet instructions until you get a smooth, thick paste like peanut butter. Do not mix too much at once as it starts to set within 20-30 minutes. For bathrooms, use a waterproof or anti-mould grout.
Apply with a grout float
Scoop grout onto the rubber float and spread it diagonally across the tiles, pushing it firmly into the joints. Work in sections of about one square metre at a time. Make sure every joint is completely filled with no gaps or air pockets.
Clean excess grout
Wait about 10-15 minutes until the grout starts to firm up, then wipe the tile faces with a damp sponge in circular motions. Rinse the sponge frequently. Do not wipe too hard or you will pull grout out of the joints. After an hour, polish off any remaining haze with a dry cloth.
Seal the grout
Once the grout has fully cured (usually 24-48 hours), apply a grout sealer with a small brush or applicator. This prevents water and stains from penetrating. Re-seal every 12 months in wet areas like showers. For corner joints and where tiles meet the bath or shower tray, use flexible silicone sealant instead of grout.
Colour Choice
White grout shows dirt fastest. Consider a light grey for bathrooms or a colour that closely matches your tiles. Dark grout with light tiles is a bold look but makes any imperfections more visible. Always test on a spare tile first as grout dries lighter than it looks wet.
Speed Tip
Use masking tape along the tile edges if you want ultra-clean lines, especially with contrasting grout colours. Remove the tape before the grout fully sets.
Common Mistakes to Avoid
- - Not removing enough old grout (new grout needs at least 2-3mm depth to bond properly)
- - Mixing too much grout at once (it sets in the bucket and you waste it)
- - Wiping too soon (pulls grout out of joints) or too late (grout haze becomes very hard to remove)
- - Using grout in corners and movement joints (these need flexible silicone sealant)
- - Forgetting to seal the grout (unsealed grout absorbs water and stains)
When to Call a Professional
If tiles are cracked, loose or the wall behind is damp, you need a tiler to investigate. Regrouting over damaged tiles or water-damaged substrates is a waste of time. Also consider a professional if you have natural stone tiles which need special grout and sealing.