A sharp rise in searches for white fungi is drawing attention to growing health and safety concerns on patios and outdoor paths, with experts warning of risks to children, pets and property as wetter winters fuel widespread growth.
New analysis shows that online searches for white fungi have risen by 195% in the past quarter. Patios and pathways are increasingly becoming hotspots for fungal spread, especially in homes where children and pets frequently come into contact with the ground.
White fungal growth is often mistaken for harmless discolouration. In reality, it represents mature stages of fungal spores and lichen that penetrate deeply into stone. When untreated, these organisms release airborne particles, reduce slip resistance and accelerate structural deterioration.
Specialists predict that the UK could experience record levels of white fungi in 2026 due to three consecutive wet winters, persistent dampness and reduced sunlight. These conditions match long-standing guidance from the Royal Horticultural Society, which links prolonged moisture to increased fungal growth on hard surfaces.
Experts warn of increasing outdoor hazards
“Most natural stone sealers are microporous, organic growth such as lichen can still grow within the stone,” says Alex Essex, outdoor surface specialist at the Patio Black Spot Removal Company. “During wet periods, algae will thrive, sealers won’t stop this and can be expensive, needing to be re-applied every few years. Instead, prevention starts with good patio design, proper drainage, reducing puddling, and allowing sunlight to reach the surface.”
The Patio Black Spot Removal Company specialises in restoring damaged stonework and promotes eco-friendly treatments that avoid harsh chemicals. Industry recommendations also encourage sustainable approaches to patio maintenance.
Health risks linked to white fungi exposure
Public health bodies, including the Centres for Disease Control and Prevention, document several health effects associated with mould and spore inhalation. The severity depends on species, contact level and personal sensitivity.
Common reactions include:
- Allergic responses: Spores from Aspergillus, Cladosporium and Penicillium can trigger sneezing, watery eyes, skin irritation, dermatitis and sore throats. Children are particularly vulnerable due to close contact with ground surfaces.
- Respiratory irritation: Inhaling spores may cause coughing, wheezing, breathing difficulties and asthma attacks. Studies from the National Institute of Environmental Health Sciences confirm heightened risks in young children.
- Mycotoxin exposure: Some white mould species release mycotoxins, which can cause headaches, fatigue and concentration problems. The World Health Organisation identifies mycotoxins as contributors to mould-related illnesses.
- Infections: People with weakened immune systems may face aspergillosis, a serious fungal infection caused by Aspergillus species. The CDC notes that while such cases are rare, they require urgent treatment.
- Mental health impacts: Visible mould and persistent dampness are linked to increased stress and anxiety, a trend highlighted in the Journal of Allergy and Clinical Immunology.
- Pets can also transfer spores indoors on paws and fur, increasing exposure inside the home. Dry spells heighten risks as disturbed fungi become airborne.
Fungal growth causes long-term damage
- Guidance from organisations such as Pavingexpert and StoneSuperstore shows that untreated white fungi can cause permanent harm.
- Pitting and etching that cannot be removed
- Cracks and structural failure caused by moisture retention and freeze-thaw cycles
- Slip hazards for children and older adults
- Recurring spread each winter
- Repair costs reaching up to £4,500 for a 30m² patio, according to 2025 UK estimates from Checkatrade and MyJobQuote
“People assume patio staining is harmless until they see what’s really happening on the stone,” says Alex. “That white fungal layer you sometimes see means the surface hasn’t been properly cleaned in 3–5 years, and by then, the fungi have already etched into the surface. You can remove the growth, but the marks will be permanent.
“With wetter, longer winters, these organisms have the perfect conditions to spread and cause structural damage. It’s a gradual weathering process that often goes unnoticed until cracks and irreversible marks appear.”
He adds: “The cost of ignoring it can be huge. Replacing even a small 30m² patio can easily reach £4,500 once materials and VAT are included. Regular care is far cheaper than the repairs homeowners end up facing when white fungi and other growths are left to take hold.”
How homeowners can protect families and pets
Experts recommend 6 steps rooted in RHS and industry best practice:
- Improve drainage to prevent puddling.
- Increase sunlight exposure by trimming hedges and winter foliage.
- Sweep regularly to remove organic debris.
- Use eco-safe spray-and-leave algae treatments during winter.
- Avoid bleach, vinegar and harsh chemicals.
- Clean early before organisms mature and bond with stone.
“Following these steps and making sure to do regular annual cleaning is the only effective way to stop these organisms establishing themselves. Once they take hold, the damage is already underway,” Alex warns.
As the UK faces another damp season, experts say early action against white fungi can help households avoid health risks and costly repairs while keeping outdoor areas safe for children and pets.