How to Clean Grout Between Bathroom Tiles Effectively

Grout is the hardest-working and least appreciated part of any tiled bathroom. Those narrow lines of cement-based filler hold your walls and floors together, yet they quietly absorb soap scum, hard-water minerals and body oils every single day. Within a few weeks a crisp white grid can look dull and grey, and no amount of wiping the tiles themselves will fix it. The good news is that you don't need specialist products or professional help. A stiff brush, a homemade paste and a bit of patience will bring those lines back to life.

Why Grout Turns Grey So Quickly

Grout is porous. Look closely and you'll see it's packed with tiny channels that grab hold of whatever washes over it. In a shower, that means shampoo residue, conditioner, body oils and the calcium and magnesium found in hard water. On the floor, it's dust, hair and the odd splash of toothpaste.

Humidity makes things worse. A bathroom that stays damp for hours after a shower gives mould and mildew exactly the conditions they need, which is why the grout around a bath or shower tray often darkens first.

Sealing grout helps to slow all of this down, but sealant wears away with regular cleaning. The practical answer is to clean little and often with gentle products rather than reaching for aggressive bleach every few months.

What You'll Need

• A stiff grout brush, or an old toothbrush for awkward corners
• Bicarbonate of soda
• Washing-up liquid
• White vinegar in a spray bottle
• Hydrogen peroxide (3%) for stubborn or mouldy patches
• Several microfibre cloths and an old towel
• Rubber gloves and a small bowl
• Optional: a steam cleaner and a squeegee

Making an Eco-Friendly Grout Paste

This paste is cheap, safe for septic systems and works as well as most shop-bought grout cleaners. In a small bowl, mix three tablespoons of bicarbonate of soda with one teaspoon of washing-up liquid. Add warm water a few drops at a time until you have something the consistency of toothpaste.

For grout that's prone to mould, replace some of the water with hydrogen peroxide. It brightens grout and discourages mould without the fumes of chlorine bleach.

One important note: don't stir vinegar into the paste. The two react and fizz, which looks impressive but neutralises most of their cleaning power. Use vinegar separately as a spray instead, and never mix it with bleach.

Mix only as much as you'll use in one session. The paste dries out quickly and loses its bite.

Working Through the Tiles, Section by Section

Start at the top of the wall and work downwards so that drips don't run over areas you've already cleaned. Spray the grout with warm water first and give it a minute to soften.

• Apply the paste along the grout lines with your fingers or an old brush.
• Leave it for five to ten minutes. This dwell time does most of the work.
• Scrub along the lines, not across them, using short back-and-forth strokes. Scrubbing diagonally across tiles mostly just polishes the tiles.
• Wipe away the residue with a damp microfibre cloth, rinsing it often.
• Finish with a clean damp cloth and dry the area with an old towel.

On floors, work in quadrants and keep the water to a minimum. Flooding the grout soaks it deeper and can loosen it over time. If a section is badly soiled, repeat the process rather than scrubbing harder.

Dealing with Stubborn Stains and Mouldy Grout

Black speckles mean mould has taken hold in the grout or the silicone sealant beside it. Spray the area with white vinegar, leave it for ten minutes, then scrub and rinse. For tougher patches, press a thick paste of bicarbonate of soda and hydrogen peroxide into the line and leave it for fifteen minutes before scrubbing.

A steam cleaner is excellent on grout, as the heat lifts grease and kills mould spores without chemicals. Keep the nozzle moving so you don't crack the tiles.

Some staining simply won't shift, particularly rust marks or old grout that has crumbled. If the grout is cracked, missing or hollow-sounding, cleaning won't solve it. Clean it thoroughly, let it dry completely, then re-grout or re-seal.

Keeping Grout Cleaner for Longer

Prevention is far easier than restoration. Keep a squeegee in the shower and use it for thirty seconds after every use, then leave the window open or the extractor fan running for ten minutes. Wipe up splashes as they happen rather than letting them dry.

A weekly five-minute routine keeps on top of things: spray the grout with a diluted vinegar solution, leave it briefly, then rinse and dry. Once a year, check whether the grout needs resealing.

It's also worth organising your supplies so the job stays quick. Keep a small caddy under the sink containing your brush, a jar of bicarbonate of soda, a spray bottle and two microfibre cloths. Wash cloths at 60°C and never put them away damp, as that's what makes a clean bathroom smell fusty. Ten minutes a fortnight is all it takes to keep those lines looking crisp.