Many rented homes suffer from black mould and condensation on windows, frames and walls. But what causes damp and how it can be treated? And who is responsible for getting rid of it?
This article answers the common questions asked about the causes of damp and mould, and how to treat this problem in rented properties.
The Causes of Damp
The first step to treating damp is to identify the cause of it. There are three main types of damp:
- Penetrating damp
- Rising damp
Causes of Condensation
Condensation is by far the most common of all damp problems and is predominantly caused by day-to-day domestic activities. Condensation occurs when there is a build up of warm, moist air and the property then starts to cool down. Moisture then condenses on cold surfaces such as windows and condensation become apparent.
People naturally release moisture into the air via respiration and sweating. Cooking, drying clothes inside, showering and other water-releasing activities also add to the buildup of warm moisture. If the moisture in the air is not regulated throughout the property then condensation problems can begin. In other words, normal tenant-like use of the property adds to the water in the air.
Condensation occurs primarily between during autumn and winter. This is when there tends to be low levels of ventilation within the property as people close the windows and doors to keep warmth in and heating bills down. Colder external air temperatures cause the moisture to condense faster and more noticeably. For example, colder window panes will quickly cool moisture in the air to a liquid state, leading to condensation on windows.
Causes of Penetrating Damp
Penetrating damp occurs where moisture is built up horizontally in the walls. The causes of penetrating damp are usually as a result of poor maintenance of the property.
Penetrating damp can occur if you have what is known as ‘an external defect’ – for example blocked guttering. If the water does not evaporate and builds up leading to water overflowing the guttering the water will eventually pass through the surface of the building.
Causes of Rising Damp
Rising damp is often misdiagnosed and confused with penetrating damp. It is the movement of moisture, rising up through the outer walls of the building. It is most commonly found in older properties where there is either no damp proof course in place or the physical damp proof course has failed. For example, in raised ground levels which have breached the height of the damp proof course.
Having no damp proof course means that the moisture will not be stopped from rising up the wall through capillary action. Rising damp will only reach a height of around one metre. The groundwater will contain salts which will then be deposited on the interior and exterior walls of the building.
How to Get Rid Of Condensation
If diagnosed early, condensation is a simple process to treat.
The main form of treatment for condensation is the improvement of ventilation throughout the property. This can be achieved through simple changes in lifestyle, such as opening windows, drying clothes outside or installing a tumble dryer.
You can also add ventilation fans to your property which will allow for the air to exit the property as soon as possible. If mould is occurring in your home you can buy mould kits which will get of rid of the mould in the short term. The most important method of treating condensation is by improving the airflow in to and out of the property. This can be achieved with extractor fans and openable windows.
Rising Damp Treatment
To fully treat rising damp, you must locate the source of moisture. A quick fix may stop the rising damp issue in the short term, but make repairs more expensive in the future.
There are damp-proofing solutions that can be used to prevent rising damp damage your property. A damp proof course is the most common form of treatment, with most modern housing already having in this place.
Older housing, usually pre-1950s, may not have a damp proof course installed. If there is a damp proof course installed it should be checked to ensure it is undamaged and functioning correctly.
Another form of treatment for rising damp is an electro osmosis system. The process of the electro osmosis damp proofing is that a series of holes are drilled on the outside of the wall just above ground level.
Anodes are then inserted into the drilled holes and these are linked by a connecting wire which is pointed into the wall. A small and safe electrical current is then sent through the anodes and connecting wire.
The electrical charge acts as to repel the moisture rising up the wall back safely back down to the ground. A constant small electrical charge is maintained to ensure the property is damp free.
How to Treat Penetrating Damp
For treating penetrating damp, similar to treating rising damp, the most important step of the process is to establish where the moisture originated from. If damp is entering the property through broken rainwater gutters or pipes then the simple way of treating the problem is by fixing the fault.
Air gaps in windows and doors can lead to penetrating damp. Filling in the gaps can help solve the problem.
Cavity walls can provide efficient protection against penetrating damp. Most modern housing is constructed with two layers of wall with a cavity placed within them. Cavity walls act as a barrier so the moisture will evaporate before it can penetrate its way through the property.
It is important to note that cavity walls can also cause damp as a result of the cavity becoming full of debris. In this case, the moisture can pass via the debris from the outer wall to the inner wall of the property.
Is the Landlord or Tenant Responsible for Damp and Mould?
It is down to the landlord to ensure that the property has enough ventilation and the proper appliances to ensure tenants are able to avoid condensation building up enough to cause mould and damp.
For example, if the property is a third-floor flat with no tumble dryer, no place to hang wet washing and no window in the bathroom, then it’s quite likely the flat will have suffer from high humidity and condensation even with considerate tenants. The problem is exacerbated the more tenants the property has.
The landlord of this property should not be surprised if the tenants complain of condensation and mould in the winter. They may wish to consider installing vents to windows, making sure extractor fans in the kitchen and bathrooms are powerful, and ensuring the heating is strong enough to warm the property and circulate air efficiently.
It is up to the tenant, however, to take all steps to prevent the buildup of condensation within the property that can cause damp and mould. This includes drying clothes outside (if possible), ensuring rooms are ventilated and using heating to evaporate water so it can escape the property.
In short, it is up to the landlord to ensure the structure is not vulnerable to damp and that the tenant is able to avoid condensation buildup as long as they take steps to do so. It is up to the tenant to take those steps and keep condensation in mind when cooking, bathing and laundering.
What to Do Next?
Dampness is a common problem across the UK. Regular checks should be made at your property to see if the building is suffering from any forms of damp. If you spot the signs early and act quickly it could save you thousands of pounds in the future.
Tenants are encouraged to report the signs to landlord as early as possible. This enables the landlord work with the tenants so they can solve the problem together.
If you are in any doubt over a damp problem we would advise you to contact a Property Care Association (PCA) qualified surveyor to carry out an inspection at the property.
This post was by Robert Owen from Timberwise. If you would like further advice about damp or property care problems that can affect your property then visit the Timberwise site.