Identify and prevent damp, mould and condensation in your property

Identifying condensation, damp and mould can be a complicated business for landlords. What are the differences between them? And who is responsible for these issues in the property – the landlord, the tenants, or both?

Understanding how to identify, treat, and prevent the development of condensation, damp and mould can help save you both time and money, as well as protecting your property from ongoing damage.

As a landlord, condensation can be a recurrent problem that often leads to wider issues such as damp and mould.

A major problem often encountered by landlords is whether condensation problems in a property are a result of issues with the property itself, such as poor ventilation or a lack of damp proofing, or caused by the tenant, or a combination of both. Either way, early identification and treatment of the issue is paramount for avoiding further issues in your property. It is important to note that condensation, damp and mould, although often similar in appearance, should be treated differently.


What is condensation?

Condensation is a common occurrence in many homes and occurs when warm moist air produced by ordinary everyday tasks, such as cooking, showering, washing or drying clothes, reaches a cold surface.  When warm moist air reaches a cold surface it condenses, leading to the development of water droplets. If the room is not well ventilated the moisture rich air is unable to dissipate and collects on surfaces such as windows in the form of water droplets. Moisture is also naturally occurring in the air and so a drop in air temperature can lead to the release of water in the form of droplets; this is commonly known as the ‘dew point’.

In some instances, however, condensation may not be visible as it collects on wallpaper, plastered walls, clothing or in carpets. Condensation collecting in this way is usually identified through a musty smell, and/or the development of mould.

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The main causes of condensation

Landlords should be aware that there are three main causes of condensation in a property:

  1. The room temperature is too cold
  2. There is a lack of ventilation in an area of high steam production
  3. The property has moisture rich air

Other causes of condensation include,

  • Lack of insulation at construction – older buildings may not have a sufficient level of insulation and are therefore more susceptible to condensation
  • Cold spots/bridging – some materials used during construction are naturally colder than others, such as concrete beams, which can be difficult to adequately insulate. A property that has been renovated or refurbished may also lose insulation during construction, which can lead to a problem with the property further down the line
  • Colder weather – condensation is more common during cold weather and is more likely to appear on cold surfaces or those that are microclimatic areas of little movement, for example behind a kitchen cupboard or wardrobe. If left untreated condensation in these areas can lead to the development of mould.


Prevention and cure

Condensation can be both a ‘landlord’ and a ‘tenant’ problem, dependent on individual circumstances. For example, a poorly working and fitted extractor fan that is not removing sufficient steam from a bathroom would be an issue that a landlord is required to attend to.

We have put together a helpful advice sheet to assist your tenants in identifying and managing the effects of damp, mould and condensation. Visit our tenant advice page for further guidance to provide your tenants with this winter.

However, tenants may also be responsible for condensation within the property; for example by drying large volumes of clothes on a radiator in an unventilated room or by blocking extractor fans. The prevention of condensation within a rental property is largely about effective landlord and tenant communication and can be easily avoided in most cases.


Guide to identifying and preventing damp, mould and condensation | Condensation on a window


Top tips to reduce the incidence of condensation include:

  • Encourage tenants to always leave background heating on in the property during colder months. While tenants may be concerned about increased heating bills, this not only protects pipework from freezing, but also helps to reduce condensation levels in the property which can prove far less costly in the long term
  • As a landlord it is important to ensure that the property is well ventilated. Make sure that there are working extractor fans in areas where moisture and steam may be produced such as the kitchen or bathroom. Importantly, landlords are advised to remind their tenants not to block any vents or extractor fans in the property
  • When it is safe to do so, tenants should be encouraged to air the property as much as possible by opening windows to help avoid condensation build up. Remember to provide details on property safety too
  • Remind tenants to close off any moisture or steam in a room, for example during and after a bath or shower, to stop it spreading throughout other rooms in the property. Did you know: having a bath produces two pints of moisture! Of which a proportion is circulating throughout the property
  • Ask tenants to avoid drying wet clothes on radiators or other heaters in the property

Landlords should encourage open and transparent dialogue with their tenants when it comes to property issues. Encourage your tenants to notify you as soon as a problem becomes apparent in order to reduce long term issues for both the landlord and the tenant.

As a landlord, dealing with these issues in a timely manner can also show your tenants that you care and are responsive. This in turn can encourage tenants to take good care of the property, which again benefits both parties. Property tips will likely be well received by tenants who will not want to live in a property suffering from condensation, damp and/or mould.

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Dampening down – dealing with damp problems in your property

Where condensation is usually caused by everyday activities in the home, dampness is more often than not a result of building defects; something that tenants are likely to have little control over, even when they are sufficiently ventilating and adequately heating the property during their tenancy.

Damp in a property is therefore most likely to be a landlord’s responsibility and is an issue that can be easily addressed with appropriate advice and guidance.

Tenants should however be made aware that their lifestyle can contribute to the development of damp in a property, for example through the excessive production of moisture. While condensation can be reduced in many instances, tenants will be restrained by property limitations such as poor ventilation or extractor fans, the responsibility for which rest with the landlord. Prolonged damp exposure can lead to structural issues with the property, so acting sooner rather than later is extremely important.

Guide to identifying and preventing damp, mould and condensation | Damp patch on wall around a plug socket

Examples of damp include:

  • Rising damp – usually caused as a result of damp proof coursing or membrane that has been breached in the walls or floor of the property. This is likely to develop over a long period of time
  • Penetrating damp – this is where rain or water from another source seeps through cracks in the brick work or tiles
  • External plumbing issues – cracked or weathered piping may introduce water into the property
  • Blocked guttering – especially common during the autumn and winter months where debris clogs pipework leading to a build-up of water which can seep into the property

Damp in a property can be caused by a number of different factors and so it is important to identify and treat the cause as soon as possible to avoid further and potentially more costly damage.


Damp patch? Spotting the signs

Signs of damp in your property can vary, however some key symptoms include:

  • A ‘damp’ musty smell
  • Dark or discoloured areas that appear on walls or plaster work
  • Damp patches that begin at the base of the wall and then gradually move upwards
  • Brown or yellow staining or a ‘tide mark’ on the wall
  • The walls or ceilings may feel cold and wet to the touch
  • Peeling wallpaper and/or paintwork
  • Damaged plaster or skirting boards

If you recognise any of these signs landlords are best advised to seek help from an experienced contractor who will be able to provide guidance on how to manage and rectify damp in the property.

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How to avoid damp in your property

If left unchecked damp can cost you dearly as a landlord. However, there are a number of ways to help avoid damp creeping into your rental property.

  • Midterm property inspections are vital for checking the property condition after the tenancy begins. This give you the opportunity to quickly identify and rectify any issues in the property before they escalate, and also offers you the opportunity to discuss any issues with the tenants in person. It is important however that you give adequate notice to your tenants before carrying out a midterm inspection. Read more here.
  • Make sure that the property is in a good state of repair by checking for common property problems that lead to damp:
    • Leaking roofs
    • Blocked guttering
    • Blocked or cracked pipes
    • Evidence of rising damp
    • Ineffective damp coursing
    • Blocked or overflowing drains
  • Make sure that the property meets the most recent insulation standards
  • Ensure that the property has a well maintained and serviced heating system
  • Be sure to fit extractor fans in areas with high moisture content
  • In areas that are partially prone to moisture it may be useful to invest in a dehumidifier to help to remove the additional moisture in the room. While this is an additional cost it could help to save you money in the long run

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What is mould?

Mould is a fungus that grows in areas with high humidity and excess moisture. It is important that landlords take mould in their property seriously. Mould can seriously impact on the health of your tenants and can often cause breathing difficulties, alongside other symptoms if left untreated.

Landlords should always encourage tenants to notify them of any mould issues within the property

and it is the landlord’s responsibility to find the cause and treat it appropriately.

The sooner mould issues are tackled the quicker they can be resolved, which is of benefit to both the landlord and the tenant.

Working together landlords and tenants can help to prevent the initial development or re-emergence of mould in the property.