Damp Specialist Warns: Mould Is a Year-Round Problem, Not Just a Winter Issue

Mould is an all-year-round problem that can pose a serious health risk, with damp and moisture issues continuing long after the winter heating season, a leading damp specialist has warned.

Black mould is far more than a cosmetic nuisance, and the scale of the problem is larger than many homeowners realise.

Government figures suggest that between 962,000 and 6.5 million homes in England are affected by damp and mould, depending on how the problem is measured. For George Edwards, Managing Director of Timberwise, that wide range reflects the scale of the issue he sees when inspecting properties across the country.

“People often think of mould as a winter problem because condensation becomes more noticeable when temperatures drop, but mould does not disappear when spring arrives,” said Edwards. “Moisture can build up in homes throughout the year, whether it is caused by condensation, leaks, poor ventilation, penetrating damp or another underlying issue.”

“Even at the conservative end, we are talking about hundreds of thousands of households living with a genuine health risk in their home, and most of them probably do not realise how serious it can become. At Timberwise, we have inspected homes where mould has gone untreated for years because nobody understood the risk until it was already affecting someone’s breathing.”

Mould is a symptom, not the underlying problem

Edwards says one of the most common mistakes he encounters is treating mould as an aesthetic problem rather than a symptom of excess moisture.

Black mould, often associated with species such as Aspergillus niger, is only the visible sign of a much wider damp problem that can have several different causes.

“People fixate on the black spots, but the moisture behind them is really what you are dealing with,” he said. “Condensation is by far the most common cause, where warm, humid air hits a cold surface in a room that does not get the chance to dry out properly.

“But we also see penetrating damp from failed roofs, gutters or windows, rising damp associated with a defective damp proof course, and traumatic damp caused by a one-off event such as a burst pipe or flood. Each one needs a different solution, which is why treating surface mould without identifying the actual cause almost never works in the long term.”

While condensation can be particularly problematic during colder months, summer does not eliminate the risk. Cooking, showering, drying clothes indoors, inadequate ventilation, plumbing leaks and external water penetration can all introduce moisture into a property at any time of year.

Health risks can vary from person to person

Government estimates have linked damp and mould in English homes to around 5,000 cases of asthma and 8,500 lower respiratory infections in a single year, alongside a proportion of new allergic rhinitis cases.

Edwards says the health impact can vary significantly depending on the individual and the extent of exposure.

“For most healthy adults, the impact may be unpleasant rather than dangerous. You can see sore throats, skin irritation and inflamed or irritated eyes,” he said. “But for children, older people, pregnant women and anyone with a weakened immune system or a respiratory condition such as asthma or COPD, the risks can be much more serious.”

The death of two-year-old Awaab Ishak in 2020 following prolonged exposure to mould in his family’s council flat in Rochdale remains the starkest example of the potential consequences of allowing damp and mould to go untreated.

The coroner found that there was no accessible, up-to-date health guidance for the housing sector at the time, with the case subsequently contributing to the creation of Awaab’s Law.

“Landlords now have clear legal duties,” Edwards said. “Homes have to be free of Category 1 hazards under the Housing Act, fit for human habitation, and social housing has to meet the Decent Homes Standard. None of that is optional, and nobody should have to wait until a problem causes serious medical harm before action is taken.”

Cleaning mould is only the first step

When it comes to dealing with mould, Edwards says the response should reflect the size and persistence of the problem.

Small areas of surface mould can generally be dealt with safely at home using an appropriate mould remover, protective gloves, a suitable mask and good ventilation. However, cleaning the visible mould is only the beginning.

“If you do not find and fix whatever is causing the damp, the mould comes straight back,” Edwards said.

Larger, recurring or persistent infestations should be professionally investigated. Once mould has penetrated materials such as plasterboard, insulation, carpet or structural timber, simply cleaning the surface will not resolve the underlying problem.

“At Timberwise, that means investigating with moisture meters to identify the source, repairing the cause, improving ventilation and, in more severe cases, using industrial drying equipment or replacing affected materials,” Edwards said.

“It is also worth checking a property again around six weeks after treatment because if the underlying cause has not been fully addressed, mould can reappear within that period.”

Prevention should continue all year

Edwards says preventing mould is largely about managing moisture consistently rather than waiting for visible mould to appear.

Ventilating bathrooms and kitchens, using extractor fans, dealing promptly with leaks, drying clothes sensibly and maintaining adequate heating during colder weather can all help reduce the moisture that mould needs to grow.

“Good ventilation and sensible moisture management are important all year round,” he said. “You should not wait until winter, or until you see black spots on the wall, before thinking about the moisture levels in your home.”

“None of that is complicated, but it has to be consistent. Mould is not simply a winter problem, and tackling it properly means looking at the condition of the whole property rather than just cleaning what you can see.”