Part of Ward Property Services UK LtdBlack mould, most commonly Aspergillus and Cladosporium species, colonises surfaces where relative humidity at the wall face stays above roughly 70% for prolonged periods. It is a biological indicator: wherever you see it, the surface has been persistently damp. Wiping it off with bleach removes the visible colony but leaves the spores, the staining and — crucially — the conditions that allowed it to grow.
Mould matters for health as well as appearance. Spores and mycotoxins can aggravate asthma, allergic rhinitis and other respiratory conditions, and vulnerable occupants are particularly at risk. Our remediation follows a containment-first approach so spores are not spread through the property during cleaning, and every job includes identifying and correcting the moisture source.
Common signs
- ✓ Black or dark green speckling on walls, ceilings and sealant
- ✓ Mould on curtains, leather goods, shoes and stored clothing
- ✓ A distinctive earthy or musty odour in a room
- ✓ Recurring growth within weeks of cleaning it away
- ✓ Occupants reporting worsening allergy or asthma symptoms
Likely causes
- • Sustained high indoor relative humidity
- • Cold surfaces caused by thermal bridging or poor insulation
- • Furniture pushed tight against cold external walls
- • Unresolved leaks or penetrating damp keeping plaster wet
- • Inadequate extraction in bathrooms, kitchens and utility spaces