Quick answerClean the surface mould, dry the room properly, improve ventilation and replace failed silicone where mould has gone behind the sealant.
DifficultyBeginnerTimeRealistic timeline: 45 minutes to 3 hours for surface cleaning depending on severity. Recurring mould, failed ventilation, leaks or mould behind silicone can require further maintenance work over several days.DIY cost£8-£35 for cleaner, gloves and clothsProfessional costDeep bathroom cleaning commonly starts from £95 depending on condition and property size
Small or medium job
Who this guide is for, and what decision it helps you make.
Best forUnderstanding the job, cost and risk before booking work.You will learnClean the surface mould, dry the room properly, improve ventilation and replace failed silicone where mould has gone behind the sealant.Next actionSend photos, postcode, measurements and deadline. We will tell you whether the next step is a fixed quote, inspection or professional visit.
DIY or professional?
Can you do this yourself?
Light surface mould on tiles, grout and painted areas can often be cleaned safely by a homeowner with proper ventilation and gloves.
Before you start
Understand the job before you touch the tools or spend money.
Light surface mould on tiles, grout and painted areas can often be cleaned safely by a homeowner with proper ventilation and gloves.
Do not treat it as a simple cleaning job if mould keeps returning quickly, there is damp plaster, failed extractor, leaks, swollen wood or mould behind silicone.
Tools and materials
What you need before you start.
Required skillsSafe cleaningVentilation awarenessBasic surface inspectionTools requiredGlovesEye protectionSoft brushMicrofibre clothsOld toothbrushSpray bottleMaterials requiredBathroom mould cleanerWarm waterMild detergentKitchen rollReplacement silicone if sealant is stained through
Safety and UK regulations
Read this before touching the job.
Safety warningsNever mix bleach with other cleaners.Ventilate the room while cleaning.Wear gloves and avoid breathing spray mist.Persistent damp or black mould may need a property maintenance assessment.UK regulations and professional limitsRental homes should be fit for habitation and landlords may need to address damp and mould causes.Bathrooms should have suitable ventilation under Building Regulations where relevant to works.
Price and timeline reality
What affects cost, duration and whether a fixed quote is possible.
Realistic UK cost rangeDIY: £8-£35 for cleaner, gloves and clothsProfessional: Deep bathroom cleaning commonly starts from £95 depending on condition and property sizePrices are guidance only. A fixed quote requires photos, measurements or inspection.What affects the priceScopeConditionMaterialsAccessUrgencyWhether inspection is requiredWhat affects the timelinePreparationProduct availabilityAccessWorking timeTesting and clean-up
Step by step
How an experienced tradesperson would think through it.
Step 1
Open the window or run the extractor. Remove towels, toiletries and bath mats.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Step 2
Wash the area first with mild detergent to remove soap scum and body oils.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Step 3
Apply mould cleaner according to the manufacturer instructions. Do not mix products.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Step 4
Agitate grout lines gently with a small brush. Do not scrape away sound grout.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Step 5
Rinse and dry thoroughly. Moisture left behind encourages mould to return.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Step 6
Inspect silicone. If the black staining is behind or inside the silicone, cleaning will not solve it; replacement is needed.
Why it matters: this stage reduces mistakes before they become expensive. Work slowly, check the result, and do not move to the next step until the area is safe and understood.
Technical note
Bathrooms fail when moisture is hidden behind a neat surface.
Rental homes should be fit for habitation and landlords may need to address damp and mould causes.
Bathrooms should have suitable ventilation under Building Regulations where relevant to works.
Decision flowMoisture control
Check ventilation, seals, grout, substrate and curing time before treating the visible finish as the whole job.
Documents, approvals and rules
What to check before the job becomes expensive.
Regulation notesVentilation, electrics, water, drainage and gas can trigger professional requirements. Do not hide services before they are checked.Useful documentsPhotos of the existing conditionMeasurements and room/property detailsProduct manuals or model numbers where relevantQuotes, invoices and certificates for previous workDo not rushDo not hide defects before they are diagnosed.Do not buy expensive materials before checking compatibility.Do not accept a vague quote for regulated or hidden work.
Cost guide
What it usually costs.
DIY cost£8-£35 for cleaner, gloves and clothsProfessional costDeep bathroom cleaning commonly starts from £95 depending on condition and property sizeTime requiredRealistic timeline: 45 minutes to 3 hours for surface cleaning depending on severity. Recurring mould, failed ventilation, leaks or mould behind silicone can require further maintenance work over several days.Best next stepCleaning
Common mistakesSpraying bleach on dirty soap scum and expecting a lasting result.Closing the bathroom door after a hot shower.Ignoring a weak extractor fan.Sealing over damp silicone or grout.Professional secretsMost bathroom mould is a ventilation and moisture-control problem, not just a dirty surface.After showers, leave the extractor running and wipe heavy condensation from glass and tiles.If silicone is peeling, stained through or soft, remove and replace it rather than painting over it.Red flagsA quote with no scope, exclusions or assumptions.Someone pushing you to start before photos, measurements or access are clear.No explanation of what happens if the job changes.Advice that ignores water, electrics, gas, structural risk or manufacturer instructions.
Before hiring anyone
Questions that protect your budget before work starts.
Ask these questionsWhat exactly is included and excluded from the price?Can this be quoted from photos, or is inspection required?What could change the price once work starts?Who supplies materials, and who carries the risk if they do not fit?What happens if hidden damage is found?How long should the job take, including drying, curing, testing or return visits?What Perfect Living needsPostcode and access detailsPhotos or short video of the issueMeasurements, product links or drawings where relevantDeadline, tenant/guest constraints and parking notesHow Perfect Living can helpSend photos, postcode, measurements and deadline. We will tell you whether the next step is a fixed quote, inspection or professional visit.If the job is simple, photos may be enough for a price range or fixed quote.If the job involves hidden defects, structure, water, electrics or high-value finishes, inspection is the safer first step.
Interesting factMost bad DIY results are caused by preparation mistakes, not the final visible step.
Run ventilation during and after showers, keep grout clean, repair failed silicone early and avoid leaving wet towels in the bathroom.
Troubleshooting
If it does not go to plan.
IssueLikely causeFix
Mould returns within two weeksPoor ventilation, cold surfaces or hidden moistureCheck extractor performance, window use and possible leaks.
Black lines stay in siliconeMould behind the siliconeRemove and replace silicone after drying the joint.
Paint flakes above showerWrong paint or persistent condensationDry, prepare and repaint with suitable bathroom paint after fixing ventilation.
Printable checklist
Before you start, check these items.
Preparation checklistOpen the window or run the extractor. Remove towels, toiletries and bath mats.Wash the area first with mild detergent to remove soap scum and body oils.Apply mould cleaner according to the manufacturer instructions. Do not mix products.Agitate grout lines gently with a small brush. Do not scrape away sound grout.Rinse and dry thoroughly. Moisture left behind encourages mould to return.Inspect silicone. If the black staining is behind or inside the silicone, cleaning will not solve it; replacement is needed.Shopping listGlovesEye protectionSoft brushMicrofibre clothsOld toothbrushSpray bottleBathroom mould cleanerWarm waterMild detergentKitchen rollProfessional decision pointsNever mix bleach with other cleaners.Ventilate the room while cleaning.Wear gloves and avoid breathing spray mist.Persistent damp or black mould may need a property maintenance assessment.
SummaryClean the surface mould, dry the room properly, improve ventilation and replace failed silicone where mould has gone behind the sealant.
Run ventilation during and after showers, keep grout clean, repair failed silicone early and avoid leaving wet towels in the bathroom.
Questions
Frequently asked questions.
Can I just paint over bathroom mould?
No. Painting over mould traps the problem. Clean, dry and fix the moisture cause first.
Why does mould grow on silicone?
Soap residue, moisture and failed sealant allow mould to sit in or behind the silicone.
When should I call someone?
Call for help if the mould is persistent, linked to leaks, behind silicone, on plaster or caused by poor ventilation.
