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Damp and mould

Damp and mould growth is a common occurrence in properties caused by excess moisture, however exposure to a high concentration of damp and mould over a prolonged term in your property can cause detrimental effects.

Damp can cause the structure and safety of the property to be compromised and mould growth can increase the likelihood of harm to physical and mental health. Effects can include increased allergies and respiratory illnesses such as asthma as well as increased cases of depression and anxiety due to the living conditions of the property.

This page is provided in order to give information on the different types of damp and mould growth, signs for tenants and landlords to look out for, causes and steps to be taken to reduce and rectify the issues.

Tenants should report any concerns to their landlords as soon as possible to allow them to investigate and rectify if necessary.

Rising damp

This affects the ground floor of a property when ground water travels up the building which can damage the plaster, timber and interior decoration of the walls.

Most commonly found in older properties, signs of rising damp can include damp and wet patches on the walls, damp odour in the property, flaking plaster and paintwork, rotting flooring and skirting boards.

Rising damp can cause damages to the plaster and decoration of the property but if left untreated, can cause substantial damage to the structure of the property.

In the majority of cases, rising damp can be rectified by instructing a qualified damp surveyor to install a damp proof course. When completed properly this should be effective for at least 20 years.

Penetrating damp

This can affect any level of the property and occurs when moisture from the exterior of the property infiltrates through to the interior. This is usually caused by a defect in the building, gutters or due to degradation of the external walls allowing moisture to travel through.  

Signs of penetrating damp can include damp staining on walls, ceilings and exterior walls, damp odour in the property and flaking plaster and paintwork.

In order to treat penetrating damp, it is recommended to organise a damp survey to identify the source of the moisture which can then be rectified using a reputable contractor.


This is the most common cause of damp and mould which occurs when a property is not heated or ventilated properly. Excess moisture inside the home circulates and touches cold walls and windows, causing a build-up of water which can soak through walls and paintwork. If the walls turn damp and cold, this can lead to mould growth. 

Black mould

Mould growth is caused when mould spores hit damp walls due to excess moisture in the property. When the moisture, temperature and conditions are right, the mould spores will quickly reproduce into new mould colonies spreading in the property.

Signs of mould can include black patches of mould on ceilings, walls, around windows and floors. Other signs include spotting on clothing, bad odour in the property, allergy and asthma flare ups and excessive moisture and condensation.

There are many steps that tenants can take in order to reduce the condensation in the property to reduce the risk of mould growth such as:

  • use extractor fans when cooking. Try to avoid cooking without lids on pots and pans as this is known to add considerable moisture to the air
  • do not dry clothes on a radiator as this increases condensation. If you have to dry clothes indoors, use a clothes airer, keep a window open or extractor fan on with the door closed
  • if there is a build-up of water droplets on the windows, wipe down the window sills daily
  • when showering, ensure any extractor fan is on with the door closed. Ensure window trickle vents are open or leave a window open to let the steam out
  • try to avoid placing furniture on an external wall as these are colder than internal walls and can trap moist air. Keep a gap between furniture and internal walls as this will allow air to circulate more freely
  • in colder months, keep the temperature in the property consistent to keep the surfaces warm to reduce condensation.

Steps that landlords can take:

  • install a bathroom fan with a humidity sensor or motion detector which would operate automatically if the tenant was not turning it on or not willing to open a window
  • install an extractor fan in the kitchen, ensure it links up to an exterior vent
  • add more ventilation, install trickle vents to existing windows to circulate air more freely
  • consider installing double glazed windows which will provide a barrier between cold weather outside and the warm air inside
  • provide a dehumidifier for the property, this will assist with maintaining the humidity levels in the property and reduce excess moisture in the air
  • if providing a vented tumble dryer, ensure the ventilation pipe leads outside of the property to ensure the moisture is released outdoors. If providing a condenser dryer, ensure it is positioned in a well ventilated room
  • consider insulating the walls of the property. As the property is kept warmer including the surface of the walls, condensation will be less likely to occur.

It is always recommended to use a qualified contractor to treat any mould growth.

If the landlord or tenant wishes to treat existing mould in the property:

  • wear a mask, rubber gloves and safety glasses
  • remove excess mould using a damp cloth and wipe affected areas down with a fungicidal wash. Throw away cloths after using
  • if the mould does not come off completely, then there may be other causes for the damp and mould that will need further investigation
  • do not brush or vacuum mould as this will release mould spores in to the air increasing the risk of respiratory illness
  • to reduce the risk of reoccurrence, after treatment redecorate any walls and ceilings with fungicidal paint
  • carpets affected by mould should be shampooed and clothes should be dry cleaned.

Tenants whose private rented property is affected by damp and mould must inform their landlord as soon as they can in order to rectify the issues raised.

For further information and how the local authority can assist, please view our unsatisfactory conditions and disrepair page.

Landlords seeking further advice can contact privatesectorhousing@telford.gov.uk.

Last updated: 18/05/2023 12:19