How to clean tile grout

Inspired by the B&Q grout cleaning guide. This walk-through draws on the step-by-step video "How to clean grout" published by B&Q on their YouTube channel - a straightforward demonstration covering grout cleaning methods, product choices, and the kind of practical detail that makes the difference between grout that looks better and grout that stays that way.

1. Work out what you're actually dealing with

Not all dirty grout is the same. Light discolouration on kitchen tiles is usually cooking grease and general grime. Dark lines in the bathroom shower are often a mix of soap scum, limescale, and mould. Each responds to slightly different treatment.

Run a damp white cloth over a small patch. If it lifts easily, surface dirt is the main culprit. If the grout still looks dark when wet, you're dealing with deep staining or mould that's worked its way into the porous surface.

2. Mix up a bicarbonate of soda paste for general cleaning

For everyday grime, bicarbonate of soda with a splash of water makes a simple, effective paste. It's mildly abrasive without scratching tiles, and most households already have a box. Mix it to the consistency of toothpaste.

You can also add a few drops of washing-up liquid to help it penetrate grease on kitchen tiles. Nothing fancy needed.

3. Apply and leave it to work

Spread the paste generously onto the grout lines. Don't rush this. Let it sit for five to ten minutes - longer if the grout is badly stained. Give it time to break down the grime rather than relying on elbow grease alone.

For commercial grout cleaners, follow the dwell time on the label. Most need a few minutes to actually do anything useful.

4. Scrub along the grout lines

Use a stiff-bristled grout brush - narrow enough to fit into the lines without going all over the tile face. An old electric toothbrush head works surprisingly well on bathroom grout where the lines are tight. Work in short strokes along the line rather than across it.

Apply a bit more paste as you go if it starts drying out. On floor tiles, a stiff hand brush or a drill-powered brush attachment saves your back considerably.

5. Deal with mould separately

If there's black mould in shower grout, bicarbonate alone won't shift it. You need a bleach-based product - a grout pen, a bleach spray, or neat white vinegar for lighter cases. Apply directly to the mould, leave for fifteen minutes, then scrub.

Good ventilation here. Open the window or run the extractor fan. Bleach fumes in a small bathroom are not pleasant.

6. Rinse thoroughly

Rinse with clean water and wipe off the residue with a damp sponge or cloth. Any cleaning product left in the grout will attract more dirt more quickly.

Buff the tiles dry with a clean cloth - avoids water marks on the tile faces and gives you a better view of how well the grout has come up.

7. Seal the grout when it's fully dry

This step gets skipped far too often. Unsealed grout is porous - it absorbs moisture, soap scum, and mildew. Apply a grout sealer with a small brush or applicator pen, let it cure overnight, then buff off the excess.

Properly sealed grout stays cleaner for much longer and resists future mould. Worth doing once a year in a shower, every couple of years elsewhere.

When to call a handyman

If cleaning makes no real difference and the grout looks patchy, crumbly, or is missing in places, it needs regrout rather than cleaning - that's a bigger job that Richard can help with. Same if tiles have started to lift or feel hollow: cleaning won't fix an adhesion problem underneath.