Best Mould Remover for Walls & Damp Areas

Black spots on bathroom plaster, window reveals and shower grout call for the best mould remover for walls & damp areas in 2026. A thick gel clings to tiles, silicone and painted walls in steamy UK rooms, where thin sprays just run off and leave stains behind. Look for a formula made for bathrooms, kitchens and other damp corners.

For stubborn growth in humid rooms, it also helps to compare the best mould remover in the UK with a dedicated mould remover spray and a specialist bathroom mould remover. If the staining has already spread across painted surfaces, follow a proper method for how to remove black mould from bathroom walls to treat the affected area thoroughly and reduce the risk of it returning.

Discover our Best Mould Remover for Walls & Damp Areas - GLEAN

Why Mould Grows on Walls and Damp Surfaces

Mould likes still, moist air and a cool surface. In many UK homes that means bathrooms after a shower, kitchens after cooking, and bedrooms where clothes dry on radiators. Warm, wet air hits a cold wall or window reveal. Water sits there. Spores already in the room settle and grow.

You will often see it first as black spotting on silicone, grey bloom on grout, or a dusty patch in a corner behind furniture. Condensation is the usual trigger. Leaks and rising damp can feed it too. Government housing advice is clear on this point. Wiping the stain without cutting the moisture only buys a short pause. The patch comes back.

The best mould remover for walls has one job. It must stay on a vertical face long enough to break the stain and the growth underneath. Thin liquids slide into the bath before they work. Gels and foams cling. That is why format matters as much as brand.

After you clean, keep steam moving out. Run the extractor. Crack a window. Wipe tiles dry. A blocked shower waste keeps the room wet for longer, so a drain unblocker liquid helps when hair and soap scum sit in the trap.

How to Choose a Mould Remover in the UK

Pick the product to match the surface, not the loudest claim on the bottle.

Painted plaster and emulsion walls. You want a formula that will not strip paint or leave a bleached halo. Test a hidden patch first. Leave it for the full dwell time.

Tiles, grout and silicone. These hold moisture in tiny pores and in the bead around the bath. A non-drip gel sits in the joint. A mist spray often runs off before it reaches the stain in the silicone.

Ceilings and high corners. Foam or gel beats a watery jet. You need contact time, not a shower of drips on the floor.

Outdoor masonry and garden walls. Indoor bathroom gels are the wrong tool. An outdoor treatment for algae, lichen and black spotting belongs on patios, brick and render. GLEAN’s outdoor range covers those wet external faces.

Also check dwell time. Some sprays ask for a few minutes. Gels made for deep black marks often need hours, or overnight, then a wipe. That extra contact is the point on walls. Ventilate the room. Wear gloves. Keep the product off fabrics, as many active cleaners can bleach cloth.

If grout still looks grey after the mould has gone, a grout reviver and sealer kit can restore colour and add a water-resistant film. That is a finish step, not a substitute for killing the growth.

Best Mould Remover for Walls & Damp Areas

1. GLEAN - Best Mould Remover for Walls and Damp Areas

GLEAN Mould Remover Gel Spray is a 500ml trigger gel made in the UK by GLEAN in Biggleswade, Bedfordshire. The thick, non-drip body is the reason it suits walls. It hangs on tiles, painted plaster, grout and silicone instead of racing into the tray. You shake the bottle, spray the mark, and leave it to work. Light spotting can shift in as little as 30 minutes. Deep black mould is left for at least 6 hours, and up to 24 hours, then wiped with a damp cloth. No heavy scrubbing is built into the method. The gel is aimed at bathrooms, kitchens and any indoor corner that stays damp. Regular use is described as helping to hold a barrier against fresh growth. The bottle has an on/off nozzle so you can place a bead along a shower seal without soaking the whole wall.

Facts and information

• Thick gel clings to vertical and overhead faces

• Made in the UK

• Targets black mould and mildew on tiles, walls, grout, silicone and windowsills

• Light marks can show a change from 30 minutes. Stubborn stains can stay coated overnight

• Smart trigger with an on/off nozzle for neat lines on seals

• Suited to bathrooms, kitchens and other moisture-prone rooms

Mould Remover Gel Spray | 500ml | GLEAN

Mould Remover Gel Spray | 500ml | GLEAN

Description

• TARGETS BLACK MOULD FAST: Cuts through black mould and mildew on tiles, grout, walls and silicone seals.

• CLINGING NON-DRIP GEL: Stays put on vertical and awkward surfaces so the formula can work deeper for longer.

• CONTROLLED TRIGGER SPRAY: Easy-squeeze bottle with on/off nozzle for precise, mess-free application.

• BUILT FOR DAMP ROOMS: Ideal for bathrooms, kitchens, showers and other high-humidity spots.

• HELPS STOP REGROWTH: Regular use keeps treated areas cleaner and reduces mould coming back.

• UK-MADE FORMULA: Quality British formulation designed to be effective and straightforward to use.

GLEAN Green Clean | Algae, Lichen, Moss & Black Spot Remover | 1 Litre & 5 Litre

GLEAN Green Clean | Algae, Lichen, Moss & Black Spot Remover | 1 Litre & 5 Litre

Description

• CONCENTRATED FORMULA: Easy to use - dilute as directed, then spray the target area with a standard garden sprayer and allow it to work. Mix 1 part GREEN CLEAN with 5 parts water before applying.

• WET IT - FORGET IT - WON'T REGRET IT: No rinse step. Coat the full surface and let GREEN CLEAN work in its own time. Once down, the treatment stays active and helps stop growth returning.

• FOR USE ON ALGAE: Timing can vary, but most green growth begins to fade within a few days of treatment.

• FOR USE ON MOSS: Soak the area so the solution reaches the surface the moss is clinging to. Within a few days the moss browns, curls and lifts away.

• FOR USE ON LICHEN: Treat twice, leaving 15 minutes between coats so the formula can penetrate the inner layer.

• NOT ONLY DOES GREEN CLEAN: Restore a growth-free finish - it also remains active to help delay early recontamination.

• SUITABLE FOR USE ON: Timber, natural and manufactured stone, roofs, tarmac, concrete, block paving and any other outdoor surface that receives rainfall.

• NO: Scrubbing, brushing, rinsing or pressure washing needed.

• COVERAGE: 100–300 m² per 5 litres

• MADE IN BRITAIN

Miracle Outdoor Cleaner | GLEAN

Miracle Outdoor Cleaner | GLEAN

Introducing our standout formula for restoring the fresh look of outdoor areas. The high-performance Brick Cleaner for Exterior use and Driveway Oil Stain Remover. Built for a wide range of surfaces, this path cleaner refreshes patios, drives and brickwork with less effort, so outdoor spaces stay clean and welcoming.

Our eco-friendly patio cleaner is a practical household staple that targets typical outdoor marks and growth. Use it as a patio cleaner for pressure washers or as a spray-and-leave treatment; it works on patios, driveways and brick exteriors.

Description

• POWERFUL OUTDOOR CLEANER: Cuts through and helps control green and black staining from mould, lichen and algae.

• MULTI-SURFACE USE: Works on concrete, brick, wood, UPVC, tarmac, natural stone and similar outdoor materials.

• FAST-ACTING FORMULA: Short dwell time and little heavy scrubbing for quicker outdoor cleaning.

• ALL-WEATHER APPLICATION: Outdoor stain remover you can apply in varied weather conditions.

• GENEROUS COVERAGE: One bottle treats up to 25 sqm, good value for patios, driveways and garden surfaces.

Discover our Best Mould Remover for Walls - GLEAN

2. Astonish Mould & Mildew Remover, Astonish

Astonish is a West Yorkshire household brand and this spray is the one many UK bathrooms already have under the sink. It is a ready-to-use trigger for mould and mildew on hard, washable faces such as tiles, grout, window frames, glass and plastic shower curtains. You spray the mark, give it a short sit, then wipe. Fresh spotting on a tiled splashback or around a tap often lifts in one go. That speed is why it gets used as a weekly bathroom habit rather than a once-a-year rescue.

It is a liquid, not a hanging gel. On a high wall or a ceiling you work in small patches so the cleaner does not race into the tray before it has done anything. Old black staining inside a silicone bead can need a second coat. The scent is milder than many chlorine-heavy bottles, yet the room still wants an open window or a running fan. Keep it off fabrics, carpets and untested paint. A hidden patch test on emulsion saves a bleached halo.

This product suits kitchens and bathrooms where you can rinse or wipe the surface after treatment. It is less of a specialist for painted bedroom plaster or for a deep, set-in seal that needs overnight contact. Pair it with dry air after you clean. Wipe the tiles. Leave the extractor on until the mirror clears. Otherwise the same corner spots again the next time the room fills with steam.

• Key features: trigger spray for tiles, grout, uPVC frames, glass and plastic curtains

• Facts and information: British household brand from West Yorkshire. Strong on everyday bathroom marks. Weaker as a cling treatment on tall painted walls. Ventilate while it works and keep it off cloth and carpets.

3. Kilrock Blast Away Mould Brush On Gel

Kilrock makes this gel in Chesham, Buckinghamshire, and the brush in the lid is the whole point. You paint the cleaner into grout lines, silicone beads and the awkward strip where the bath meets the tiles. A mist spray often misses that joint or runs off before it soaks in. The gel stays where you put it, so contact time is longer on a vertical seal.

Use it when the stain sits in a narrow line rather than across a whole wall. Coat the joint, leave it to dwell, then wipe. Stubborn black in old silicone may still need a second pass. The pack is a brush-on size, so a full ceiling or a large run of painted plaster is slow work. Gloves matter. The formula is sticky by design and you do not want it on skin or on a coloured towel.

Kilrock sits in the trade and home-improvement aisle more than the supermarket end cap. That shows in the way the gel is built for a precise job, not a quick spritz of the whole cubicle. After the mould has gone, the bead can still look tired. Replacing failed silicone does more than another coat of gel if water is getting behind the seal. Keep the room aired while the product sits and rinse tools when you finish.

• Key features: brush-on gel for grout, silicone and tight bathroom joints

• Facts and information: UK factory brand in Buckinghamshire. Precise on seals and corners. Less practical for large flat walls. Leave a proper dwell, then wipe. Keep off fabrics that can bleach.

4. Dettol Mould and Mildew Remover

Dettol’s mould spray comes from Reckitt in Slough and is sold as a bathroom cleaner that also deals with germs on hard, non-porous surfaces. The bottle is a large trigger, so it covers a shower cubicle, basin surround and tiled splashback without constant refills. You spray, wait a few minutes, then rinse or wipe. On ceramic tiles and open grout that you can wash down, results show quickly.

It is a bleach-based liquid. That helps on pale tiles and on soap-scum film that sits with the mould. It is a poor match for painted plaster, wallpaper, carpets and most fabrics. The smell is sharp in a small bathroom with the door shut. Open a window. Run the fan. Keep children and pets out until the surface is wiped and the air has cleared.

This is a supermarket staple for a reason. People know the brand and they can pick it up with the weekly shop. It is not a cling gel, so overhead work and tall painted walls need extra care to stop runs. Deep staining inside silicone often fades rather than vanishing in one short dwell. Use it on fittings you can rinse. Dry the room afterwards. A clean tile in a still-steamy box will spot again.

• Key features: large trigger for tiles, grout, sanitaryware and many plastics

• Facts and information: Reckitt brand from Slough. Fast on rinse-off bathroom fittings. Not first choice for painted walls or fabrics. Short dwell. Strong odour. Needs airflow and a wipe or rinse.

5. Cillit Bang Black Mould Remover

Cillit Bang, also from Reckitt in Slough, is sold as a no-scrub spray for black mould in showers, around sinks and on tiled walls. The pitch is speed. You coat the stain and the dark film often breaks down without a hard brush. That makes it popular for a grimy cubicle that has been left too long.

The cleaner is fierce. Fumes build in a windowless bathroom. Surfaces on the “do not use” list need a proper read of the label before you spray. Wood, some unsealed tiles and colour-sensitive finishes can mark. It is a thin spray, so a ceiling or the top course of wall tiles can drip. Work from the bottom or shield the floor if you are treating a high band.

Many households use this as a first attack on a neglected shower, then find the silicone bead still holds a grey line. That bead often needs a gel that sits in the joint, or a full strip and recaulk if the seal has failed. After treatment, rinse what the label allows and dry the area. Speed on the stain does not replace extraction and heat. If the room stays wet, the black film returns in the same corners.

• Key features: spray-and-wipe action on tiles, grout and bathroom fittings

• Facts and information: strong on visible black marks. Short contact on many jobs. Check the label on painted, wooden or porous faces. Ventilate well. Liquid format can run on vertical walls.

6. Polycell 3-in-1 Mould Killer Spray

Polycell sits in the Dulux decorating family and this spray is aimed at rooms you plan to paint, not only at a weekly shower clean. It is sold as a killer, cleaner and surface treatment before you recoat a stained wall or ceiling. That matters in UK bedrooms and living rooms where condensation has printed through emulsion.

You treat the patch, allow the product to work, and then prepare the wall as the label directs. The fungicide note is stronger than a light supermarket mist. Airflow is not optional. The smell can linger in a closed room. Keep it off surfaces you do not intend to wash or redecorate. Test paint. Some finishes dull or lift if the formula is too aggressive.

This is the wrong bottle if all you want is a quick wipe of a tile splashback. It is the right type of product when the stain is on plaster and you need the wall ready for an anti-mould topcoat later. It will not fix a cold bridge or a blocked trickle vent. Clean, dry, then decorate. Painting over a still-damp patch just traps the problem under a fresh film.

• Key features: indoor spray for walls and ceilings ahead of painting

• Facts and information: familiar in UK decorating aisles. Built as prep for stained plaster more than as a daily tile spray. Follow the label on papered and painted faces. Leave the room aired until it has settled.

7. Dryzone Mould Remover and Prevention Kit

Dryzone is made by Safeguard Europe in Redhill, Surrey, a firm known for damp work rather than supermarket sprays. The kit pairs a remover with a follow-on treatment meant to slow new growth. That two-step idea suits a bathroom or bedroom that keeps spotting in the same place after a single wipe.

You still have to deal with the moisture. A prevention coat on a wall that runs with condensation every morning will not hold forever. The sprays are thinner than a hanging gel, so you need even coverage on plaster and a careful hand on ceilings. The kit format is for a whole room more than for one short run of shower silicone.

This option makes sense when the house has a known damp habit, weak extraction, or a history of return growth after ordinary bathroom sprays. It is more process than a single spritz. Read both labels. Allow drying time between steps. Then change how the room handles steam. A kit cannot replace an extractor that no longer pulls, or a wardrobe jammed against a cold external wall.

• Key features: dual-action kit for washing off mould and treating the surface after

• Facts and information: UK damp-specialist brand in Surrey. Aimed at rooms with repeat growth. Works best with better ventilation and heat. Not a spot gel for a single joint.

8. Furniture Clinic Mould Remover Spray

Furniture Clinic is based in Hexham, Northumberland, and is better known for leather, fabric and wood care than for bathroom bleach. Its mould spray is built to treat spores on furnishings and timber as well as some household surfaces. That is a different job from whitening a tile grout line.

Use it on a wardrobe back, a leather chair, a timber window board or fabric that has picked up spotting in a damp room. Always test colour. Dyes and finishes vary, and any wet cleaner can leave a tide mark if you soak a patch and leave it. After treatment the item must dry. A wet sofa cushion in a cold bay window will spot again.

On ceramic tiles and bathroom silicone this is not the strongest stain bleach. Those faces still favour a gel that clings in the joint. The value here is the wider material list. Mould in a home is not only a shower problem. It sits on stored clothes, on the back of furniture and on untreated wood. Pair the spray with airflow and a gap behind large pieces so the wall can dry.

• Key features: spray for mould on furnishings, wood and some household surfaces

• Facts and information: UK specialist maker in Northumberland. Broader than tile-only sprays. Gentler on materials that chlorine products can mark. Test colour. Dry the item fully after wiping.

9. Ecozone Bleach-Free Mould Remover

Ecozone is a UK brand that sells a bleach-free mould remover for people who want to avoid chlorine indoors. There is no swimming-pool smell and less risk of that harsh bleach splash on a coloured grout or a nearby towel. For light mildew on a windowsill or a pale bloom on a tile face, that milder route can be enough.

Heavy black staining packed into old silicone is another matter. Bleach-free formulas often need more time and may still leave a shadow on a deep bead. You treat, wait, wipe, and judge the mark in good light. Repeat if the label allows. Do not assume a gentler bottle will match a trade gel on a neglected cubicle.

It still needs the same room habits as every other remover. Open the window. Wear gloves if the label says so. Keep it off untreated or untested paint. After the surface looks clean, dry it. Bleach-free does not mean moisture-proof. If the wall stays cold and the air stays wet, fresh growth finds the same corner. Use this when the household wants a softer indoor cleaner and the outbreak is still at an early stage.

• Key features: bleach-free spray for indoor mould and mildew marks

• Facts and information: UK brand aimed at milder indoor use. Better on light growth than on old, set-in black beads. Still needs ventilation and a dry room after cleaning.

10. Everbuild 404 Fungicidal Wash

Everbuild, part of Sika and long tied to Leeds, sells this fungicidal wash to decorators and builders. You apply it to walls, masonry and similar faces to clean organic growth before you decorate. It is a wash, not a bathroom gel. You treat an area, allow contact, then move on to preparation and paint.

That makes it useful on a large stained wall in a utility room, a ceiling patch before emulsion, or masonry that has picked up growth. It is clumsy for a neat line of shower silicone. You would not choose it as a weekly cubicle spray. Follow the safety notes on skin, eyes and ventilation. This is closer to site work than to a scented supermarket bottle.

Once the wash has done its job, the wall must dry. Then you decide on a stain block and a topcoat if you are decorating. The wash does not waterproof the room. If the patch sits on a cold external wall with no airflow, the spotting can return through the new paint. Use it as a prep step in a wider fix, not as the only action in a steamy bathroom.

• Key features: wash for mould and organic growth on walls before finishing

• Facts and information: trade-facing UK brand. Good as wall prep on plaster and masonry. Less precise than a brush gel on bathroom seals. Follow the label on contact time and personal protection.

11. Kilrock Mould Spray

Kilrock’s trigger spray sits beside the same brand’s brush-on gel and comes from the Chesham factory. It is the faster, broader coat when you want to treat a tiled wall or a window frame rather than paint a single joint. Spray the face, allow the dwell, wipe or rinse as directed.

On tall painted plaster it can run, which is why the gel remains the better match for grout and seals. On a shower side panel or a run of ceramic tiles the spray is quicker to put down. The formula is strong, so the same rules apply. Gloves. Airflow. Keep it off carpets and clothes. Test paint if you move beyond tiles.

Having both a spray and a gel in one UK range is useful. Treat the open tile with the spray. Treat the bead with the gel. Then dry the room. A second Kilrock bottle will not help if the extractor is dead and washing is drying on the radiator every night. Use the spray for coverage. Use the gel when the product must stay in a narrow, vertical line.

• Key features: trigger spray for mould and mildew on hard bathroom surfaces

• Facts and information: UK-made companion to the brush-on gel. Fast to apply on tiles and frames. Can run on high painted walls. Best on non-porous faces with a proper wipe after the dwell.

12. Pro-Kleen Mould and Mildew Remover

Pro-Kleen is a British cleaning brand that sells a mould and mildew remover aimed at walls, ceilings, tiles and other indoor faces that pick up spotting in damp rooms. It is offered in household sizes and in larger bottles for people treating more than one wall. The pitch is a straightforward spray or apply, wait, and wipe, rather than a decorating-aisle wash.

Coverage is the appeal on a whole bathroom ceiling or a long landing wall. A tiny brush gel cannot coat that area in one sitting. A thinner liquid can. The trade-off is the same as every spray. On a vertical face you watch for drips. On painted emulsion you test first. On silicone you may still want a thicker product that sits in the joint overnight.

Treat it as a room-scale cleaner, then finish the seals with something that clings if the bead stays grey. Dry the surfaces. Keep steam moving out. Large bottles tempt people to soak a wall and walk away. Follow the contact time instead. More product on the floor is not more cleaning on the stain.

• Key features: indoor mould and mildew treatment for walls, ceilings and tiles

• Facts and information: UK cleaning brand with household and larger pack options. Suited to wider wall areas. Less targeted than a brush gel on shower seals. Test paint and ventilate during use.

13. Jeyes Fluid Outdoor Cleaner

Jeyes is a long-running British name and Jeyes Fluid is the outdoor cleaner people reach for on paths, walls and garden faces that have turned green or black. It is not a bathroom silicone gel. It belongs on masonry, patios and external walls where rain, shade and organic growth sit on the surface.

You dilute as the label says, apply, and allow the treatment to work. Results on heavy growth can take time, especially on porous brick. Rinse where the instructions require it and keep the mix off plants you want to keep. Indoor painted plaster and shower enamel are the wrong place for a garden fluid.

This entry sits here because damp areas are not only indoors. A north wall, a shady boundary and a wet patio grow the same family of stains that people describe as mould. Using a bathroom spray outside wastes the bottle and can streak paint or metal. Using an outdoor fluid in the shower is worse. Match the product to the weather side of the house, then keep indoor gels for tiles, grout and internal walls.

• Key features: outdoor treatment for organic growth on paths, masonry and external walls

• Facts and information: historic UK brand. Built for exterior damp faces, not bathroom silicone. Dilute as directed. Keep off indoor paint, fabrics and fixtures that are not listed on the label.

How to Stop Mould Coming Back After Cleaning

Cleaning removes what you can see. The room still makes steam every day. Lasting control is about water, air and warmth.

Keep bathroom doors shut while you shower, then let the fan run until the mirror clears. A short burst of fresh air beats a window locked all winter. Dry washing in a room with an open vent, not on a cold external wall. Leave a gap behind wardrobes so air can move. Wipe window boards in the morning if they bead with water.

Grout that stays dark after treatment often still holds moisture. A tile and grout sealer helps shed splashes. Cloudy shower screens hold film that stays wet. A shower glass cleaner and descaler keeps glass clear so droplets run off instead of sitting in place.

Outdoor walls and north-facing render pick up green and black growth from rain, not shower steam. For those faces, Green Clean is the outdoor treatment in the GLEAN line. Indoor gel does not replace it.

If the patch returns in the same place within days, look for a leak or a cold bridge, not another bottle.

When Bathroom Walls Need More Than a Spray

A remover cannot fix broken pointing, a failed extractor, or a bath seal that lets water into the wall. Soft plaster, peeling paint and a musty smell that never lifts point to a building fault. In rented homes, landlords have a duty to deal with damp and mould, not only to wipe the stain.

Once the wall is dry and the growth is gone, you can refresh the look. Stained grout can take a grout reviver. Failed silicone can come out with a silicone sealant remover before you run a new bead. Floor tiles that stay dull after mould treatment often only need a porcelain floor and tile cleaner rather than another bleach pass.

For products across kitchens and bathrooms, the indoor range groups the wall, tile and shower cleaners in one place. Treat the mark. Dry the room. Then keep steam from sitting on the same cold corner. That sequence does more than a second bottle of the same spray.

FAQ

What is the best mould remover for bathroom walls in the UK?

A thick gel that stays on the wall is the better match for bathroom tiles, grout and silicone than a watery mist that runs off. GLEAN Mould Remover Gel Spray is made for those vertical, damp faces and can sit on the stain for hours so the formula reaches into the joint, not just the shiny tile face. Everyday spotting on easy-to-rinse tiles can still respond to a short dwell. Match the format to the surface, give the bottle the time it asks for, and keep the room aired while the product works.

Can I use a mould remover on painted plaster?

Many bathroom formulas are built for tiles and seals, not emulsion, so a hidden test patch comes first. If the paint fades, blisters or sheds, stop and switch to a product sold for walls. After treatment the plaster needs to dry fully before you decorate, or the mark can print through the new coat. Cold external walls and window reveals in UK bedrooms often hold condensation, so the wall must be dry and the room warmer and better ventilated if you want the finish to last.

How long should I leave mould gel on walls?

Follow the label and match the wait to how set-in the stain is. Light film on tiles can start to lift from about 30 minutes up to a few hours. Deep black mould on grout and silicone often needs at least 6 hours, and sometimes overnight, before a wipe with a damp cloth. Cutting that dwell short is why a wall can look unchanged. Keep children and pets away from wet product, wear gloves, and give the room fresh air while the gel sits.

Does bleach stop mould coming back?

Bleach can lighten a stain on a hard, non-porous face, but it does not dry the room or warm a cold wall. Spores sit in pores, in silicone and in the air, so a wet, still corner grows a new patch. A suitable mould remover for walls deals with the visible growth. Lasting control then comes from extraction, a little fresh air, even heat, and wiping condensation off sills and tiles. A blocked shower trap that keeps the floor wet works against all of that, which is why clear waste pipes sit alongside the clean.

Why does mould return on damp walls and outdoor surfaces?

The stain comes back when moisture stays. Steam from showers and cooking, clothes drying indoors, and cold external walls all feed indoor growth. Outdoor brick, render and patio joints pick up rain, shade and organic growth instead, so an indoor bathroom gel is the wrong product there. Green Clean and other treatments in the outdoor range are aimed at those wet external faces. Indoors, stained grout that still holds water can take a grout reviver and sealer after the mould has gone, and a room that stays steamy needs the fan and a dry wall more than a second coat of cleaner.

Read Also:

• Best Composite Door Restorer UK: GLEAN vs Other Door Colour Restorers

• Best Paving Grout for Patios & Driveways

• Patio Jointing Compound: Complete Guide to Brush In Patio Grout

• Best Outdoor Patio Grout for All Weather

• Patio Grout Mistakes to Avoid

Discover our Best Mould Remover for Walls in 2026 - GLEAN