Damp, whether caused by flooding, gradual ingress of water or condensation, can cause mould to grow on walls and furniture and make window frames rot. It is a health and safety issue as it can cause a variety of health problems, as well as being unsightly and causing a musty odour. In schools, PE changing rooms and showers are particularly susceptible.

Here, we:

  1. Explain why mould develops in the first place;
  2. Describe the health conditions linked to mould;
  3. Highlight the need to address the root causes, rather than just the symptoms;
  4. Set out how to remove mould once the cause has been tackled; and
  5. Include a checklist for NEU health and safety representatives.

What causes mould to develop?

Mould is everywhere, inside and out. Some moulds are good – penicillin for example. Some are toxic and emit gases. Although some people are more affected than others, all moulds have the potential to cause illness. Mould reproduces by generating spores that are released into the air where they land on moist surfaces. The spores can grow on wall paper, ceiling tiles, carpet and wood and thrive in dark, warm, moist locations.

What health conditions are associated with mould?

Inhalation of mould spores can lead to, or exacerbate, a wide range of illnesses/medical conditions. Mould can trigger allergic reactions and asthma attacks. Complaints of flu-like symptoms, migraines, dizziness, nausea and memory impairment are common. Very young children, the very old and those with immune system deficiencies are particularly susceptible. This is not a definitive list and advice should always be sought from a GP if it is suspected that mould is causing illness or exacerbating an existing condition.

Presence of mould in schools

There are many reasons why mould may be present in a school. It is important to deal with the root cause rather than simply removing it. Without addressing the source of the problem, it will no doubt recur. Mould may be found in schools because of:

  • a one-off flood 
  • structural damage, for example missing roof tiles or leaky window frames or leaky plumbing/blocked gutters
  • condensation
  • rising damp due to a defective damp course or because there is no damp course.

Condensation Mould in Schools

There is always some moisture in the air. If the air gets colder it cannot hold all the moisture and tiny drops of moisture, or condensation, appear and run down walls and windows. The best ways of removing condensation in schools are to increase ventilation, draught proof windows and ensure that the premises are kept consistently warm. Dehumidifiers can also help in some cases, but may make the air excessively dry.

Other causes of mould

If it is unclear why the mould has appeared, an investigation will be needed to isolate the cause and cure the problem before treating the mould.

How should mould be treated?

Once the underlying cause has been addressed, the mould can be removed. This is not a job for teaching staff or support staff whose job description does not include cleaning. Maintenance staff should seek advice as to whether they are competent to undertake the job or whether a specialist needs to be hired.

It is important not to disturb mould and spread the spores further by brushing or vacuuming it as this can increase the risk of respiratory problems.

Mould can be removed using diluted thick household bleach, which will kill the mould and help prevent regrowth. It is important to use a paint brush to avoid contact with the bleach and wear gloves. Bleach must never be mixed with other chemicals and adequate ventilation should be provided. Alternatively walls and window frames can be wiped down with a fungicidal wash which carries an HSE ‘approval number’. The manufacturer’s instructions should be followed precisely. It is important to wear suitable eye protection and a mask to avoid breathing in mould spores and dust.

After treatment, walls and ceilings should be redecorated using a fungicidal paint. When wall papering, a paste containing a fungicide should be used to prevent further mould growth. Of course, such treatment should take place when classrooms, or other areas, are unoccupied.

Checklist for NEU Health & Safety Representatives

  • Speak to senior management and maintenance staff about any mould growth and ensure governors are aware of the problem.
  • Ensure the area is isolated. Where the problem is acute, pupils and staff may need to be relocated.
  • Ensure root causes are addressed, whether the need for remedial work, or poor maintenance standards.
  • Ensure school staff do not attempt to treat areas themselves, or brush away mould.
  • Ensure areas are unoccupied during treatment.
  • Request details of treatment from management and recommend a regular schedule for inspecting roofs, ceilings, walls, floors and carpeting for water leakage and mould growth or mouldy odour, where this is not already in place.
  • Suggest simply strategies for prevention of mould problems. For example, if carpets are due to be steam-cleaned, suggest that this is undertaken in circumstances where the carpets can dry out in a warm and well-ventilated environment. Doing such work, for example, just before Christmas and leaving damp carpets to dry out in a cold building will encourage the development of mould.
Mould in schools

This briefing explains why mould develops in the first place and highlights the need to address the root causes, rather than just the symptoms.