Not only can damp problems in the home cause life-threatening health issues, they can also damage your bank account, with repairs bills running into the thousands.
Giles Fallan, CEO of Buildsafe, said that shocking numbers of property owners completely miss the early warning signs of moisture damage until their homes suffer major structural problems.
The building warranty specialists found that up to 27% of homes in the UK suffer from issues linked to damp and mould, with fixes costing anywhere from £300 for small problems to over £5,000 when serious structural damage takes hold.
“Dampness and mould don’t just attack your property, they also attack your body,” Fallan said. “They primarily hit the airways and lungs, but they can also harm the eyes and skin. The respiratory effects can cause serious illness and, in the most severe cases, death. Homeowners must spot these warning signs before a minor issue becomes a health emergency.
“As well as physical illness, the strain of finding damp and mould in your home can impact your mental health. Each year, the NHS spends an estimated £1.4 billion annually on treating illnesses associated with living in cold or damp housing. When wider costs such as healthcare are considered, that figure rises to £15.4 billion.”
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Latest government data showed a staggering 904,000 English homes suffered damp problems in 2023, with 11% of rented homes affected compared to just 2% of owner-occupied homes.
Buildsafe’s CEO explained the seven signs of damp and mould in your home.
What to look out for
1. Mould growth: The first warning signal homeowners must watch for is mould growth appearing on walls, ceilings or window areas. Fallan said: “Black or green patches on walls, particularly in corners or behind furniture, aren’t just ugly, they signal serious moisture problems needing immediate attention.
“Many homeowners mistake this for simple dirt or grime, but mould spreads rapidly through your home and creates dangerous conditions for everyone living there.”
2. Peeling wallpaper or flaking paint: This is the second critical warning sign of moisture secretly seeping through your walls and destroying your home from within.
“Water trapped behind wallpaper or paint destroys adhesives and causes visible deterioration of your wall coverings,” Fallan warned. “This isn’t just about how your home looks as it tells you moisture has already penetrated your walls and is creating the perfect breeding ground for harmful microbes.
3. Persistent condensation forming on windows: Window condensation looks harmless but creates the perfect environment for dangerous mould growth over time.
Installing proper ventilation systems stops this developing into problems that cost thousands to fix and put your family’s health at serious risk.
4. Musty smells: This sign is often detectable before you spot any visible damage in your home.
“That distinctive musty smell comes from mould spores already multiplying inside your walls and signals hidden moisture damage,” Fallan advised.
“If this smell hits you when entering enclosed spaces like cupboards or bathrooms, you need to take action immediately before the problem spreads throughout your entire property.”
5. Deteriorating window frames or skirting boards: This is a sign that they have already begun to rot from excess moisture.
Fallan said: “Wood absorbs moisture like a sponge and becomes soft when wet, leading to serious structural problems throughout your home.
“You can easily test skirting boards and window frames by pressing them with your thumb. If they feel soft or spongy, you’ve already got dampness problems that need urgent attention.”
6. Cold or damp spots appearing on walls: These can indicate the sixth warning sign of potential trouble brewing behind your plaster.
“Walls with cold or damp patches you can feel when touching them, point to serious insulation failures or moisture already penetrating your home, “ warned Fallon. “These cold spots quickly become breeding grounds for black mould that can trigger asthma attacks and respiratory problems.”
7. Rising tide marks on walls: These marks, particularly near floor level, reveal the seventh and most serious sign of dampness problems that could cost thousands to fix.
“Tide marks or white salt deposits on lower walls clearly show rising damp moving upward through your brickwork from ground level,” Fallan explained. “This always requires professional intervention and typically costs thousands to properly fix as it involves installing new damp-proof courses and often replacing ruined plaster and flooring.”
According to government research, damp and mould dramatically increase the risk of respiratory conditions, allergies, and asthma attacks, with young children and the elderly facing the highest danger.
The cost of damp and mould
The price of fixing damp problems varies wildly depending on what’s causing the moisture and how far it’s spread through your home. Simple condensation issues might cost £300-£500 to solve with better ventilation systems, while penetrating damp typically sets homeowners back between £1,000-£3,000.
“Rising damp hits your wallet hardest, often costing between £3,000-£5,000 or even more, because it requires installing a completely new damp-proof course and new plaster and flooring throughout the affected areas,” said Fallan, Buildsafe’s CEO.
“Prevention through regular home checks such as cleaning gutters and checking insulation, along with fixing small issues can immediately save thousands compared to major remediation work once moisture has thoroughly penetrated your property.
Research from a Parliamentary briefing uncovered that older properties built before 1919 suffer the highest levels of damp problems at 10.3%, while newer homes built after 1981 see just 1% affected by similar issues. The briefing also mentioned that 9.1% of city centre homes were likely to have damp.
The World Health Organization strongly advises against trying to set “acceptable levels” of mould in homes, instead stressing that dampness and mould problems must be prevented entirely or fixed immediately when discovered as they significantly increase exposure to harmful microbes and chemicals. To avoid or mitigate damp and mould, homes should be heated to around 18°C (65F) during the winter. However, with energy costs rising, this might be out of reach for some families and older people.