Mould after water damage grows when materials stay damp for too long after a leak or flood. Removing it properly means fixing the source of the moisture, removing materials that can’t be cleaned, cleaning what can, and drying the area so it doesn’t return. Bleaching the surface on its own rarely solves it.
Signs of mould after a leak
- A musty, earthy smell in a room that had a leak.
- Black, green or grey spots on walls, ceilings, skirting or the back of furniture.
- Mould on carpet grippers or the underside of flooring.
- Staining that keeps coming back after cleaning.
Leak mould or condensation mould?
Not all mould comes from a leak. Condensation mould tends to appear on cold external walls, window reveals and behind furniture, and gets worse in winter with drying clothes and poor ventilation. Leak-related mould is usually centred on a wet patch with a clear source. Moisture readings tell them apart — the cure is different for each.
How we deal with mould after water damage
- Find and fix the moisture source — often with leak detection.
- Assess the extent with moisture readings and a visual check, including hidden areas such as behind skirting and under floors.
- Contain the area so spores aren’t spread through the property.
- Remove porous materials that are heavily affected, such as plasterboard, insulation, underlay and carpet.
- Clean and treat remaining surfaces.
- Dry the structure with dehumidifiers and air movers to stop regrowth.
Health and safety
People with asthma, allergies, breathing conditions or weak immune systems, and babies and older people, can be more sensitive to mould. If anyone in the home has symptoms, speak to your GP. Large areas of mould, and mould in properties that may contain asbestos, should be dealt with by professionals — don’t scrape or sand it yourself.
Preventing mould after a leak
- Start drying within a day or two of the leak.
- Don’t replace flooring or decorate until readings show the area is dry.
- Ventilate kitchens and bathrooms, and keep some background heat on.
- Don’t push furniture tight against cold external walls.
Tenants and landlords
If you rent, report mould and any leak to your landlord or letting agent in writing, with photos. Landlords are responsible for repairs to the structure and to water installations, and for keeping the home free from serious damp and mould hazards. We can provide a clear record of the cause and the moisture readings.
What affects the cost?
The size of the affected area, how much has to be removed, whether the area needs containing, and how long drying takes. See the cost guide.
Mould removal across Merseyside
Older homes with solid walls and cellars in Anfield and Walton, and flats in Bootle and Birkenhead are common places to find mould after a slow leak. Treating mould is part of our wider water damage restoration work across Liverpool.
When to call a professional
If mould covers more than a small patch, keeps returning, followed a leak, or is affecting someone’s health, call 07777 659786.