Mould on grout isn’t uncommon, especially in high-moisture areas such as bathrooms and kitchens. Not only is it ugly, unwelcome, and hard to ignore, but it can also be hard to remove. Grout attracts moisture, and if left on the surface, it will eventually penetrate the grout, encouraging mould to grow.
Introducing the best bathroom extractor fans is a solution that can help remove humidity from the air. However, once mould takes hold, you’ll need to deal with it, and the sooner the better.
Is it possible to remove mould from grout?
Yes, it is possible to remove mould from grout, and this guide offers a range of tried-and-tested techniques to solve the problem. However, how successful it will be will depend on how long the mould has been left to sit on the grout.
In some cases, the grout may be beyond repair and require replacement. Regrouting tiles will undoubtedly give you a fresh new look, but it is a time-consuming process. Stephen Russell of Ashley Cross Tiling explains how to remove the old grout. “To lessen the chance of scratching the tile, get a sharp utility knife and run along the edge of the tile and grout. This means you don’t need to get so close to the edge of the tile when using your grout removal tool.”
There are a few options here, continues Russell, “You can use a manual grout removal tool, but this can be hard work and slow.” He adds, “Alternatively, use a power tool, like an angle grinder with a masonry disc for larger grout lines or a multi tool with a suitable blade.”
He finishes by saying, "This can be a messy job, so put down dust sheets, and wear a mask and safety googles.”
Stephen is an independent tiler with over 30 years in the industry. He specialises in kitchen tiling, walls and floors and general tiling repairs.
10 ways to remove mould from grout
1. Use the power of elbow grease
Before cracking out the chemicals or mixing up any homemade cleaning products, it is well worth trying a good old-fashioned scrub to see whether it can bring your grout back to gleaming.
Steve Jenkins, DIY expert, says, “Get a bucket of warm water, add a squirt of washing up liquid and get a fresh kitchen scrubber.” He adds, “Put on a pair of rubber gloves and start scrubbing.” You can use an old toothbrush or nail brush (like this Wooden Nail Brush from Amazon). After scrubbing an area of grout, rinse it with warm water to see how it looks. If needed, scrub again.
You can also buy special grout brushes, designed specifically for the job — try this set of four grout brushes from Amazon.
Steve Jenkins is a freelance content creator and a keen DIYer with over 20 years of experience in transforming and renovating the many homes he has lived in. He specialises in painting and decorating, but has a wide range of skills gleaned from working in the building trade for around 10 years.
Try these products to remove mould from grout
A compact handheld steam cleaner that comes with a host of attachments to tackle mould on grout and clean a host of other surfaces. Heats up and is ready to use in five minutes.
Bicarbonate of soda is a natural, eco-friendly, safe and inexpensive cleaning product. This 500g pack will provide enough powder to clean an entire bathroom and leave you enough to do it all again.
This bottle of concentrated lemon juice is ideal for helping remove mould from grout. Simply spray onto mouldy grout, leave for 15 minutes and rinse off for fresh grout and a lovely lemon smell.
2. Try one of the many bleach removal methods
We have heard great things about this first method of cleaning grout and it really does take minimal effort — although you will need to stock up on cotton wool.
All you need is some cotton wool pads – the bigger the better – and a bottle of household bleach. Be sure to protect your clothes, skin and any soft furnishings in the vicinity before you begin.
A note here, this is a method that is going to work best on the grout of floor tiles or other horizontal surfaces where the cotton pads won't slide off down walls.
Soak the cotton pads in bleach before covering your grout lines with them and leave for up to 12 hours. In this time, the mould will, hopefully, disappear. Wash off the bleach and dispose of the cotton wool.
Alternatively, make a bleach spray by combining water and bleach in a reusable spray bottle, apply to the affected areas, leave for around 30 minutes then rinse away.
Some people also swear by making a paste out of bleach and bicarbonate of soda, scrubbing it into the grout and leaving it for 15 minutes or so. You can then rinse it away with clean water.
3. Give whitening toothpaste a try
Yes, really, apparently whitening toothpaste is good for more than just your smile.
Use a scrubbing brush or old toothbrush (or one of the tools mentioned above) to work whitening toothpaste into the grout lines until the mould stains begin to lift. The idea behind this solution is that the slightly abrasive nature of this type of toothpaste with bicarbonate of soda or whitening agents, will help eliminate unsightly mould spots.
4. Remember that vinegar is good for more than chips
Where would we be without this trusty store cupboard staple? Cleaning vinegar is a great all-round natural cleaning solution that can work on all kinds of stains and can be used for removing mould from walls, wood and silicone sealant too.
In the case of grout, you may well find that this is a technique that will only help with light stains. Fill a spray bottle with half warm water, half white vinegar before spraying it on to the grout. Leave for 5-10 minutes before scrubbing away with a brush.
Using a vinegar spray regularly on grout can help prevent mould from forming in the first place too.
5. Make a DIY solution with bicarbonate of soda
Bicarbonate of soda is the secret ingredient for many homemade cleaning solutions, and it works well on grout. To create a homemade mould-busting solution, simply mix bicarbonate of soda and white vinegar.
Jenkins says, “Mix one cup of white vinegar with a couple of teaspoons of bicarbonate of soda. You can add more for a thicker paste.” He adds, "Work the solution into the grout with a cloth or toothbrush, and leave for 15-20 minutes. To finish, rinse off the paste.”
This is also a great way to remove black mould from silicone sealant.
6. Get fresh with lemon juice
Not only could lemon juice help with mould stains on grout, but it will also leave your room smelling fresh and zingy too.
Cleaning experts recommend spraying lemon juice over the affected areas, leaving it to get to work for around 15 minutes then washing it away with warm water and a scourer or scrubbing brush.
Alternatively, apply the lemon juice by slicing a lemon in half and rubbing it directly onto the mouldy grout.
7. Splash out on a specialist mould cleaning spray
If you have tried the above methods and had no luck then it is probably time to give some of the best grout cleaners a try.
Although there are plenty of grout cleaning sprays on the market, many of these are designed to tackle dirt, stains and discolouring as opposed to mould — so it is better to pick a mould removal spray, unless the grout cleaner you are considering specifically states it is effective on mould.
HG Mould Remover Spray from Amazon consistently receives rave reviews and costs around £6. Another highly-rated product for removing mould from grout is Dettol Anti-Bacterial Mould and Mildew Remover.
8. Give a grout pen a go
Grout pens are a good way to give mouldy grout an instant refresh — but be aware they mask stains rather than remove them. Jenkins says, “Grout pens can be a good short-term solution.” He adds, “After a while, their effect will wear off, and the grout will need to be redone.”
To use a grout pen (like these GLEAN Grout Reviver Pens from Amazon), thoroughly clean the grout, removing as much mould, dirt, and debris; rinse, and leave to dry. Then apply the pen. Leave to dry and redo if needed.
9. Consider a deep cleanse with a steam cleaner
If you happen to be the owner of a steam cleaner then you are in luck – they can be a great way to remove mould from grout – particularly those that come with grout cleaning attachments.
Before getting started, spray the affected areas with a solution of equal parts vinegar and water and let this sit for 15 minutes. You can then get to work with your steamer, holding the nozzle close to the mouldy spots you want to eliminate.
The heat of the steam will not only help with stains, but it will also kill spores.
10. Refresh by sanding and sealing
If the mould stains in your grout are deeply ingrained in the surface, you can remove the top layer and seal it with a specialist sealer, shares Jenkins. “Get a fine sandpaper grade, P120 or 180 grit will do, and wrap it around the end of a paint scraper and start sanding with a steady hand.”
Once the surface layer is gone, sweep and wipe the tiles clean, vacuum up any dust and finish with a grout sealer, such as this Vividye grout sealer from Amazon. This will help protect the grout from water and stop mould forming.
How to prevent mould on grout
Once you have removed the grout mould in bathrooms or kitchens you will no doubt be keen to prevent its return.
There are several steps you can take:
- Check for leaks: Internal leaks caused by bad pipework, blocked gutters and failed roofs can all cause water penetration which, in turn, will cause damp — and damp usually equals mould too.
- Improve the room's ventilation: If you haven't got one already, invest in a good quality extractor fan. In addition, open windows daily to get fresh air circulating around the space.
- Clean the grout down daily: Natural sprays made from vinegar and lemon will help prevent mould, as will many readily-available bathroom cleaners.
- Do a daily dry down: A quick wipe of walls and floors with an old towel will really help to stop the problem returning.
Mould on grout is caused by constant exposure to moisture, so it's important you know how long it takes for grout to dry before it is exposed to any moisture. Get water on grout too soon, and its will become a breeding ground. Check out our cleaning grout guide for keeping it fresh and if it's time for new tiles, then take a look at our where to buy bathroom tiles guide.
