Hearth & Lawn

The best mould removers for walls, grout and silicone

Last updated: · By the Hearth & Lawn team

How we chose these: We haven't tested these products ourselves, and we couldn't find a large independent lab test of mould sprays. Which? says it hasn't tested mould removers. Our picks are based on what's in each product (from labels and safety data sheets), the makers' directions, UK retailer listings and owner ratings, and a published hands-on comparison by Glasgow Live (May 2026). Prices were checked on 18 October 2026.

A mould spray can shift the black spots on a bathroom ceiling, window seals or the corner of a bedroom wall in minutes. It won't stop them coming back. Mould grows where moisture sits, so the long-term fix is less moisture and more ventilation. Our condensation and black mould guide covers that.

Two things to know before you buy:

  1. Most mould sprays are chlorine-based. Cillit Bang, Dettol, HG and Astonish mould sprays all contain sodium hypochlorite, the active ingredient in bleach. They bleach stains away quickly, but they carry the same warning: never mix them with other cleaners.
  2. UK government guidance says mould and mildew products should be used "in preference to bleach" for health and safety reasons. The guidance also says that while most people can reasonably remove condensation and very small amounts of mould themselves, larger areas should be dealt with by professionals.

Quick picks

Pick Best for Type Size Price checked 18 Oct 2026
HG Mould, Mildew & Algae Remover Spray Best overall for grout and seals Chlorine-based spray 500ml £5.40 at Screwfix
Cillit Bang Black Mould Remover Fast results on tough bathroom mould Chlorine-based spray 750ml £4 at Sainsbury's (£3.50 with Nectar)
Astonish Specialist Mould Blast Best budget spray Chlorine-based spray 750ml £2.50 at Sainsbury's
Scrubb Mould Shield Bleach-free option for walls and fabrics Bleach-free fungicide 500ml £6.59 at Screwfix
Scrubb Blast Off Mould Remover Gel Silicone seals and vertical grout Chlorine-based gel with brush 250ml £8.99 at Screwfix

We also considered Dettol Antibacterial Mould & Mildew Remover (750ml, £4 at Sainsbury's, or £3.50 with Nectar). It's another chlorine-based spray, with 2.59% sodium hypochlorite according to Dettol, and a sensible everyday bathroom option. We left it out of the main picks because we found less evidence on how it copes with stubborn staining.

How to choose a mould remover

Chlorine-based or bleach-free?

  • Chlorine-based sprays (most supermarket mould sprays) remove the black staining as well as the mould, which is why they look so effective. They can lighten coloured surfaces and fabrics, so test a hidden patch first, and check which surfaces the label rules out. HG's spray, for example, is not for wood.
  • Bleach-free products such as Scrubb Mould Shield use a different fungicide. They don't bleach staining away as dramatically, but they're the option to look at for painted walls, fabrics and coloured surfaces, or if you'd rather avoid chlorine fumes.

Spray or gel?

Sprays cover walls, ceilings and tiles quickly. Gels cling to silicone seals and vertical grout lines, so the product stays where the mould is instead of running off.

Mould in silicone sealant

Mould often grows into soft silicone, not just on it. If the black marks are still there after two treatments, the stain is probably permanent. Cutting out the old sealant and resealing is usually the only real fix.

How to remove mould safely

These precautions come from UK government guidance and NHS inform, plus the product labels:

  1. Check it's a small job. UK government guidance says most people can remove condensation and very small amounts of mould themselves. Get professional help for larger areas, and if you rent, report it to your landlord in writing first.
  2. Some people shouldn't do it. NHS inform says babies and children, older people, people with asthma, allergies or other breathing problems, skin conditions such as eczema, or weakened immune systems should stay away from mould as much as possible. Ask someone else.
  3. Protect yourself. Wear rubber gloves, goggles and a mask. Open a window and shut the door to the rest of the house.
  4. Never mix products. The HG label carries the warning: "Do not use together with other products. May release dangerous gases (chlorine)." That applies to every chlorine-based spray here. Don't use them straight after a limescale remover or toilet cleaner, and rinse the surface between products.
  5. Follow the label for how long to leave it, and test a hidden patch first.
  6. Rinse or wipe off, then let the area dry fully.
  7. Bin or wash the cloths straight away, and wash your clothes afterwards.

Throw away badly affected soft items such as carpets or soft furnishings if they can't be cleaned. Government guidance says it may be difficult or impossible to remove mould completely from absorbent materials.

Stop it coming back

Cleaning only treats the symptom. To stop mould returning:

  • Ventilate. Run the extractor fan during and after showers and cooking, and keep trickle vents open.
  • Wipe windows and tiles dry in the morning.
  • Dry washing in one ventilated room, or use a dehumidifier.
  • Keep rooms evenly warm. Cold walls attract condensation.

A small compressor dehumidifier is cheap to run. At the Ofgem price cap of 26.32p per kWh, a 216W model running 8 hours a day uses 0.216 × 8 = 1.728kWh, which costs about 45p a day. Many switch off automatically once the room reaches the humidity you set, so real costs are usually lower. See our best dehumidifiers for picks.

Work out your own figures with our running-cost calculator

If mould keeps coming back within weeks despite all this, there may be a leak, penetrating damp or a building defect.

The best mould removers in detail

1. HG Mould, Mildew & Algae Remover Spray: best overall

Price checked: £5.40 at Screwfix, marked down 20% (18 October 2026).

Key facts (Screwfix listing and label):

  • 500ml trigger spray with a targeted, low-splash spray
  • Chlorine-based ("anti-mould cleaner with bleaching effect")
  • For grout, seals, tiles and other damp areas; indoor and outdoor use, but not on wood
  • Hazard warnings include skin and serious eye irritation, very toxic to aquatic life, and the chlorine-gas mixing warning
  • Rated 4.8 out of 5 by 73 Screwfix customers

"HG mould remover" gets around 3,600 UK searches a month, more than any other brand we checked. In Glasgow Live's grout comparison it was the tester's favourite: after the 30 minutes the label asks for, the mould wiped away and the grout came up white. She also found it the most pungent of the three products, "very bleach-like", so open the windows.

Pros

  • Highly rated by owners, and the favourite in a published grout test
  • Targeted spray reduces splashes

Cons

  • Smaller bottle than supermarket sprays
  • Strong chlorine product: ventilate well

2. Cillit Bang Black Mould Remover: fast results on tough mould

Price checked: £4 at Sainsbury's, or £3.50 with a Nectar card until early November (18 October 2026).

Key facts:

  • 750ml trigger spray
  • Chlorine-based: 2.19g sodium hypochlorite per 100g, according to retailer ingredient listings
  • Rated 4.6 out of 5 by 129 Sainsbury's customers

Easy to find in supermarkets and well rated by owners. It's a strong product, so wear gloves, protect your eyes and ventilate the room. We didn't find an independent side-by-side test of it, which is why it's second rather than first.

Pros

  • Well rated by owners
  • Widely available and cheap

Cons

  • Strong fumes
  • Can bleach coloured surfaces

3. Astonish Specialist Mould Blast: best budget spray

Price checked: £2.50 at Sainsbury's (18 October 2026).

Key facts:

  • 750ml trigger spray
  • Contains sodium hypochlorite, according to its ingredient listing
  • Rated 4.6 out of 5 by 13 Sainsbury's customers

The cheapest spray here. In Glasgow Live's test it was runny and ran down the tiles, but after 10 minutes the mould "wiped away in one wipe". The tester felt it didn't penetrate as deeply as the HG spray. It's the one to buy to keep on top of a bathroom that gets the odd spot.

Pros

  • Very cheap
  • Fine for regular maintenance

Cons

  • Less punchy on old, deep staining
  • Few retailer reviews so far

4. Scrubb Mould Shield: best bleach-free option

Price checked: £6.59 at Screwfix (18 October 2026).

Key facts (Screwfix listing):

  • 500ml spray; bleach-free fungicidal treatment
  • For walls, floors, ceilings, fabrics and tiles
  • Maker says it leaves a protective barrier against regrowth
  • Rated 4.7 out of 5 by 10 Screwfix customers

For painted walls in bedrooms, or where bleach would mark the surface, a bleach-free product is the safer bet. It's newer and has few reviews. It may not lift old black staining as dramatically as a chlorine spray.

Pros

  • No chlorine
  • Can be used on more surfaces, including fabrics

Cons

  • Less proven, few reviews
  • Won't bleach out old stains

5. Scrubb Blast Off Mould Remover Gel: best for silicone

Price checked: £8.99 at Screwfix (18 October 2026).

Key facts (Screwfix listing):

  • 250ml thick gel with built-in applicator brush
  • Contains chlorine-based bleaching agents
  • For tiles, grout, shower seals and window frames
  • Rated 4.6 out of 5 by 9 Screwfix customers

A gel stays put on vertical seals and grout lines, so it works longer where you need it. If the staining is deep inside the silicone, though, no gel will fully clear it. That's the point to reseal.

Pros

  • Clings to vertical surfaces
  • Built-in brush for corners

Cons

  • Small tube for the price
  • Still a chlorine product, with the same warnings

FAQs

What is the best mould remover for walls? For painted walls, try a bleach-free product such as Scrubb Mould Shield first, and test a hidden patch. Chlorine sprays work fast but can mark paint and wallpaper. If an area of wall is badly affected, get professional advice, and fix the moisture problem.

What kills black mould permanently? Nothing you spray on will stop it for good if the room stays damp. Cleaning removes what you can see; less moisture, more ventilation and warmer walls stop it returning.

Is it safe to use bleach on mould? UK government guidance says mould and mildew products should be used in preference to bleach for health and safety reasons. Many mould sprays still contain chlorine, so follow the label, ventilate, wear gloves and goggles, and never mix products.

How do I remove mould from silicone? Use a gel, leave it as long as the label allows, then rinse. If the black marks remain after a second go, the mould has grown into the sealant, so cut it out and reseal.

Does vinegar kill mould? Which? suggests washing-up liquid and warm water for small areas, and a 1:1 white vinegar solution for more stubborn mould. Never mix vinegar with a chlorine product.

My landlord says the mould is my fault. Is that right? UK government guidance says landlords should tackle the underlying causes of damp and mould, not blame tenants' "lifestyle". See what your landlord must do.

Sources