Two jobs, not one.
Cleaning deals with the growth you can see. Diagnosis deals with the moisture, cold surface, leak or ventilation condition that allowed it to return.
For rented homes, report damp and mould to the landlord or managing agent and keep a dated record. Current government guidance says the underlying causes and health risks need to be addressed, not reduced to blame about household behaviour.
Record
Take dated photographs, note affected rooms and record whether the problem changes after rain, cooking, bathing or colder weather.
Stay safe
Follow the product instructions, ventilate appropriately and do not disturb extensive growth or contaminated materials without suitable advice.
Find the cause
Check extraction, cold surfaces, leaks, outside defects and any damp building materials. Recurrence is a reason to investigate further.
Look beyond the mould patch.
- Humidity and surface conditions
- Ventilation and extraction
- Roof, gutter, plumbing and wall defects
- Heating, occupancy and recent alterations
Clean now, investigate as well.
For a small, accessible area, follow the product instructions and avoid spreading spores through brushing or dry sanding. Do not mix cleaning products. If growth is extensive, keeps returning, follows a leak or involves porous materials that cannot be cleaned safely, pause and ask for appropriate professional advice.
Cleaning is not a substitute for repairing a leak, restoring extraction or dealing with a cold, wet surface. A dehumidifier may help temporarily, but it does not explain where the moisture is coming from.
Give the investigation a useful starting point.
- Room, wall or item affected, with dated photographs.
- Whether the mould returns after cleaning and how quickly.
- Condensation, humidity, cooking, bathing, drying clothes and heating patterns.
- Any roof, plumbing, window, gutter or external-wall issue.
- Who has been told, what was cleaned and which repairs have been attempted.
Official health and ventilation advice.
GOV.UK: health risks of damp and mould explains why visible mould should be removed and the underlying cause addressed. GOV.UK: existing home ventilation guide covers moisture, airflow, trickle vents and extractor maintenance.
Cleaning and recurrence.
Should I photograph mould before cleaning it?
Yes, if it is safe. Dated photographs can help show the extent and location before cleaning, especially for a rented property.
Does cleaning mould remove the underlying problem?
No. Cleaning removes visible growth; the moisture source or conditions that allowed it to grow still need to be addressed.
When should I get professional help?
Seek appropriate help for extensive growth, recurring mould, water damage, vulnerable occupants or signs of leaks, structural issues or unsafe electrics.