How to Clean Grout Between Bathroom Tiles
Clean dirty grout with bicarbonate of soda paste and a stiff brush, then escalate to vinegar or oxygen bleach for deep stains. Seal afterwards to keep it clean.
Quick answer
Scrub the grout with a paste of bicarbonate of soda and water. For tougher stains, spray diluted white vinegar, let it fizz, then scrub again. Rinse, dry, and seal with grout sealer to stop stains returning quickly.
Grout stains easily in damp bathrooms. Start with the gentlest method and escalate only if needed. Sealing the grout after cleaning keeps it white for months.
What you’ll need
- stiff-bristled grout brush or old toothbrush
- bicarbonate of soda
- white vinegar
- spray bottle
- oxygen bleach gel (optional)
- grout sealer
- grout whitener pen (optional)
- cloth
- steam cleaner (optional)
Step by step
- 1
Identify whether the grout is dirty or mouldy
Grey or brown surface grime is cleanable. Black spots that penetrate the grout are mould and may need bleach or re-grouting. Know which problem you have before you start.
- 2
Apply bicarbonate of soda paste
Mix bicarbonate of soda with a little water to form a thick paste. Spread it along the grout lines and scrub with a stiff brush or old toothbrush. This removes most surface grime without harsh chemicals.
- 3
Spray diluted white vinegar on mineral deposits
For harder water marks or lingering stains, mix equal parts white vinegar and water in a spray bottle. Spray onto the grout, let it fizz for five minutes, then scrub and rinse.
- 4
Treat deep discolouration with oxygen bleach gel
If the grout is still stained, apply an oxygen bleach gel and leave it for the time stated on the label. Scrub, rinse thoroughly, and ventilate the room well.
- 5
Rinse and dry thoroughly
Wipe away all residue with a damp cloth, then dry the tiles and grout with a clean towel. Leftover cleaner can attract new dirt.
- 6
Seal the grout lines
Once the grout is completely dry, brush or sponge on one coat of grout sealer. It dries in about an hour and creates a barrier that repels moisture and stains.
Never mix bleach with vinegar or other acids — this produces chlorine gas, which is dangerous in a small bathroom. Use one product per session, ventilate the room well, and keep the window open or the extractor fan running. Check product labels before combining anything.
Common mistakes
- Mixing bleach with vinegar — produces chlorine gas.
- Scrubbing with metal scourers — scratches glazed tiles permanently.
- Skipping ventilation — bleach fumes build up quickly in an enclosed bathroom.
Frequently asked
Why does my grout turn black again so quickly after cleaning?
Unsealed grout is porous and absorbs moisture and grime. One coat of grout sealer after cleaning creates a barrier that keeps it cleaner for months.
Is it safe to mix bicarbonate of soda and white vinegar for grout cleaning?
Yes, but they neutralise each other and are less effective combined than used sequentially. Apply soda paste first, scrub, then spray vinegar if needed.
How do I know if I need to re-grout rather than just clean?
If mould has penetrated deep into the grout or the grout is crumbling and cracked, cleaning the surface will not help. Re-grouting is the only fix.
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