Many people think mould is a winter problem, but it can thrive just as easily in summer. In fact, warmer temperatures combined with higher humidity levels and frequent spells of rain followed by sunshine create the ideal conditions for mould spores to grow and spread around the home.
The issue is more common than you might think. In England alone, around two million people – equivalent to three to four per cent of homes – are estimated to be living with mould. Beyond causing unsightly black patches, peeling paint and musty odours, mould can quietly spread behind furniture, inside cupboards and on hidden surfaces.
Left untreated, mould can do more than damage your decor. Prolonged exposure has been linked to respiratory problems, poorer indoor air quality and structural damage to properties, making it particularly important to keep an eye out for signs of growth during the humid summer months.
'The reality is that summer can be just as problematic [as winter] because warmer temperatures and increased humidity can also create a breeding ground for mould,' says Andy Ellis, plumbing engineer and bathroom expert from Vidalux.co.uk.
'The combination of warmth and moisture can really accelerate mould growth, especially in poorly ventilated areas like bathrooms.'
Regular checks and timely intervention are crucial to keep your home safe this season and beyond. To help you spot mould early, we've rounded up seven telltale signs.
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1. Increased humidity in certain rooms
Mould thrives in warm, damp environments, making the summer months an ideal time for growth. If certain areas of your home suddenly feel more humid than usual, hidden mould could be the cause. This is particularly common in poorly ventilated spaces such as bathrooms, utility rooms and cellars, as well as around leaky pipes or windows where moisture can build up unnoticed.
2. A persistent musty smell
An earthy, musty odour that won't go away is often one of the earliest signs of mould. You may notice it in cellars, lofts or behind large pieces of furniture. The smell is caused by gases released by mould colonies, so even if you can't see the mould, the smell can indicate hidden growth behind walls or under flooring.
3. Condensation on windows
If your windows are steaming up more frequently than usual, it could be a sign that there's too much moisture in the air. This is especially common in kitchens and bathrooms where steam levels are naturally higher. Keep an eye on window frames and seals, as mould often appears here first.
4. Discoloured walls and ceilings
Unexpected yellow, brown or greenish marks on walls and ceilings can point to a moisture problem. These stains can appear when water seeps through surfaces, creating the damp conditions mould needs to spread.
Areas near leaking roofs, plumbing issues or poorly insulated external walls are particularly susceptible, so it's important to investigate any unexplained marks as soon as they appear.
5. Peeling, bubbling or cracked paint
Paint that begins to blister, bubble or peel away from the wall can be a warning sign of trapped moisture. In some cases, mould may already be growing beneath the surface. Left untreated, the problem can spread and potentially cause more extensive damage to your home's structure and decor.
6. Rooms that feel damp or stuffy feeling
If a room constantly feels damp, stale or stuffy even if you air it out regularly, hidden mould could be to blame. Mould often develops in areas with limited airflow, for example, behind furniture, beneath carpets or inside wall cavities. A lingering damp feeling is a telltale sign that indoor moisture levels are too high.
7. Respiratory symptoms
Are you or members of your family sneezing or coughing more than usual? Are sore throats or itchy eyes a problem that worsens when you're inside? Mould releases allergens and irritants into the air, which can trigger or worsen respiratory symptoms. People with asthma, allergies or other sensitivities are often the first to notice a problem.
