Damp, mould & condensation

Complaints about damp and mouldy properties are common especially during the winter months when condensation is more likely to occur. Disputes between landlords and tenants concerning who should take action to remedy a damp and/ or condensation problem are also not unusual owing to the complex range of factors that can lead to the problem occurring. This page will provide you with helpful information about what can be done to alleviate damp and mould problems and what we can do to assist.

Types of Dampness

There are four main types of dampness that could affect your home. It is important to understand the difference between them so that you can effectively treat the problem.

1. Rising Damp

This is caused by water rising from the ground into the home. The water gets through or round a broken damp proof course (DPC) or passes through the natural brickwork if the property was built without a DPC. A DPC is a horizontal layer of waterproof material put in the walls of a building just above ground level. It stops moisture rising through the walls by capillary action.

Rising damp will only affect basements and ground floor rooms. It will normally rise no more than 12 to 24 inches above ground level (300mm to 600mm) and usually leaves a ‘tide mark’ low down on the wall. You may also notice white salts on the affected areas.

Rising damp will be present all year round but is more noticeable in winter. If left untreated it may cause wall plaster to crumble and paper to lift in the affected area.

Note. Black mould will rarely be seen where there is rising damp (and then only in the early stages). This is because rising dampness carries with it ground salts which prevent the growth of black mould.

2. Penetrating Dampness

This type of dampness will only be found on external walls or in the case of roof leaks, on ceilings. It only appears because of a defect outside the home, such as missing pointing to the brickwork, cracked rendering or missing roof tiles. These defects then allow water to pass from the outside to the inner surfaces.

Penetrating dampness is far more noticeable following a period of rainfall and will normally appear as a well-defined ‘damp-patch’ which looks and feels damp to the touch.

Note. Black mould is rarely seen on areas of penetrating dampness. This is because the affected area is usually too wet and the dampness contains salts picked up when passing through the wall, which prevent the growth of black mould.

3. Defective Plumbing

Leaks from water and waste pipes, especially in bathrooms and kitchens, are relatively common. They can affect both external and internal walls and ceilings. The affected area looks and feels damp to the touch and remains damp whatever the weather conditions outside. A quick examination of the water and waste pipes serving the kitchen and bathroom and the seals around the bath, shower and sinks; plus the external pipe work, such as guttering will usually find the source of the problem.

Note. Black mould will rarely be seen on this type of dampness because the area is usually too wet and the chemicals in a waste water leak will prevent mould growth.

4. Condensation (most common)

This is by far the most common cause of dampness experienced by tenants and householders, resulting in a large number of enquiries or complaints received by the Council. Condensation is caused by water vapour or moisture from inside the dwelling coming into contact with a colder surface, such as a window or wall. The resultant water drops (condensation) may then soak into the wallpaper or paintwork or even plasterwork. In time, the affected damp areas then attract black mould that grows on its surface.

Condensation mainly occurs during the colder months, whether it is rainy or dry outside. It is usually found in the corners of rooms, north facing walls and on or near windows. It is also found in areas of little air circulation such as behind wardrobes and beds, especially when they are pushed up against external walls.

Note. Black mould is frequently seen on this type of dampness.

Condensation and Mould Growth

Most homes will be affected by condensation at some point. However, certain activities will increase the humidity levels in a property and make condensation more likely to occur. Whether you are an owner-occupier or a rent-paying tenant, condensation and mould growth can occur more often due to habits and lifestyle, and is something that can be reduced or remedied by the occupant. Cooking, washing, drying clothes indoors, even breathing - all produce water vapour that can only be seen when tiny drops of water (condensation) appear on colder surfaces such as walls, windows, ceilings or mirrors.

The ‘amount’ of condensation in a home depends upon three factors:

humidity levels and how much water vapour is produced by the actions of its residents
how cold or warm the property is
how much air circulation (ventilation) there is

Simply turning up the heating will not sort out the problem, this may only temporarily reduce condensation. All three factors may need to be looked at to reduce the problem. The first sign of a problem is water vapour condensing on windows and other cold surfaces, which then takes a long time to disappear, allowing surfaces to become damp. The second indication is black mould patches growing on these damp areas.

Black mould

Mould spores are invisible to the human eye and are always present in the atmosphere both inside and outside dwellings. They only become noticeable when they land on a surface upon which they can grow and then multiply.

Mould is formed when the spores grow on damp and humid surfaces, causing the characteristic black patches and a characteristic “damp” smell. You may find this link useful to assist you in understanding the issues of damp and mould further.

For mould to thrive and survive it requires four elements:

Moisture - obtained from condensation
Food - such as wallpaper or emulsion paint
Suitable temperature - courtesy of the householder
Oxygen - courtesy of mother nature.

By dealing with the causes of condensation you will automatically deal with the problem of mould.

Problems that damp and mould can cause

As well as being unsightly, damp and mould can affect your health. This can mean that you are more likely to have respiratory problems, respiratory infections, allergies or trigger asthma. Damp and mould can also affect the immune system. Over a period of time damp and mould are likely to cause damage to the property, so it is important that you make your landlord aware of the issue, if you rent your home.

For further information about liability for repairs in private rented homes and how to report an issue to your landlord, please visit our repairs page.

Common household moisture producing activities

The following gives you some idea of how much extra water you could be adding to the air in your home in a day:

2 people at home for 16 hours	3 pints
A bath or shower	2 pints
Drying clothes indoors	9 pints
Cooking and use of a kettle	6 pints
Washing dishes	2 pints
Bottled gas heater (8 hours use)	4 pints

How to stop condensation

You get less condensation if you try to keep your home warm most of the time. Whenever possible open a window while cooking, running hot water or drying clothes. There are four steps you can follow to help stop condensation.

Step one - produce less moisture

Ordinary daily activities can produce a lot of moisture very quickly. So when you are cooking -

put lids on pans
do not leave kettles boiling
open windows

When you are drying your clothes, wherever possible try to dry them outside. If you have to dry inside -

try to avoid drying clothes on radiators. If you do, open windows slightly to give some ventilation
dry them on a clothes rack in the bathroom with the door closed and either an extractor fan on or a window slightly open.
make sure your tumble dryer is always ventilated to the outside unless it is the condensing type

Step two - ventilate to remove moisture

Keep a small window or trickle vent (fitted in the window frame) open when the room is in use. By opening windows or ventilating your home it may appear that you are losing some heat, but what you are actually doing is allowing warm moisture-laden air to escape and permitting cool dry air to enter your home. Dry cool air is actually cheaper to heat than warm moist air!

You need much more ventilation in the kitchen and bathroom when cooking, washing up, bathing and drying clothes. You should open windows wider or use a humidistat controlled electric fan (these come on automatically when the air becomes humid and are cheap to run).

Stop damp air from spreading by keeping kitchen and bathroom doors closed when the room is in use.

Open bedroom windows for up to one hour as soon as you get up, and throw back the sheets or duvets to air the bed and bedding.

Leave space between the back of furniture and cold walls.

Ventilate cupboards and wardrobes and try not to put too many things in them as this prevents air circulating. Where possible put them on internal walls rather than against outside walls.

When you have curtains or blinds drawn, it makes the surface of the window colder and this increases condensation. Try to open curtains or blinds for at least four or five hours each day.

Do not completely block chimneys and flues – fit with an air vent and make sure you meet ventilation requirements for any gas appliances in a room.

Step three - keep your home warm

We know this is difficult given current energy prices, but wherever possible try to heat your home using gas central heating or electric storage heaters. Do not use paraffin or portable gas heaters as these put a lot of moisture into the air.

Good heating controls on your radiators, room thermostats and a timer will help control the heating throughout your house and manage costs.

You can add draught proofing but remember do not -

block permanent vents
draught proof rooms where there is condensation or mould.
draught proof where there is a cooker or a fuel burning heater, for example, a gas fire

Insulate the loft up to at least a depth of 10 inches (25cm).

For information about energy efficiency and grants available in Doncaster, please see the energy saving advice and grants page.

If you are struggling to heat your home due to the cost of living, you can find advice and support on our Cost of Living pages

Step four - treatment for mould growth

If you already have mould growth in your home, it must be treated. If you deal with the basic problem, mould should not reappear.

A solution of water and vinegar will remove light mould staining on hard surfaces (such as painted surfaces). To kill and remove mould, wipe down walls and window frames with a fungicidal wash which carries a Health and Safety Executive approved number. Remember always use rubber gloves and wear safety glasses. Follow the manufacturer's instructions precisely. Dry-clean mildewed clothes and shampoo carpets.

Tea Tree oil is a natural antiseptic and disinfectant but it’s also great for cleaning especially on mould or mildew. Try a dilute of three to four drops of Tea Tree oil in two litres of water (hot or cold). Soak mildewed items in the solution or spray on to trouble spots using a plant mister. Wipe, then rinse off. Always ensure you carry out a test on small area of the fabric/material/surface beforehand.

After treatment

Redecorate using a good quality fungicidal paint or wall paper paste to help stop mould coming back. You should be aware that this paint is not effective if covered with ordinary paints or wallpaper.

Remember…… Dealing with condensation is not easy. Only carrying out one or two of the above steps may not solve your problem. You need to do as many as possible every day.

What does the law say if damp or mould is causing a problem in my home?

This is primarily covered by the Housing Act 2004. The Council uses the Housing Health and Safety Rating System (HHSRS) to assess housing conditions which utilises a risk assessment approach. To learn more about how we use this system, please visit our page concerning housing standards.

Where the damp and mould is caused by a property deficiency or defect (rather than just normal day to day use of the property and not following the steps to reduce condensation described above, etc), then an assessment of the likelihood that it will cause harm and the consequences of this will lead to it being rated as either a category 1 hazard (where the local housing authority must take some type of formal action to require the landlord to reduce the risk sufficiently) or a category 2 hazard (where the local housing authority may take formal or informal action, depending on the circumstances).

The Council has enforcement powers under the Housing Act 2004 where landlords fail to carry out works they are responsible for. To learn more about how we make enforcement decisions and what our legal powers are, please visit our page concerning enforcement of standards in privately rented property. This page also contains information about taking your own legal action against your landlord (commonly referred to as "civil action").

What can I do if I think damp and mould in my rented property is caused by a defect or deficiency?

If you think that there is a physical defect for example, rising damp, a leaking pipe or damaged roof tile/chimney flashing, insufficient insulation or the heating does not work properly and that is causing the damp and mould, contact your landlord or managing agent as soon as possible. They will usually be keen to put this right and minimise any damage being caused. Please visit our repairs page for advice about how to report repairs to your landlord and what to do if they fail to act.

Your landlord must carry out repairs within a reasonable period of time - but that only begins once you've told them about the problem. For example, if you report an emergency repair such as a leaking pipe it could be reasonable for your landlord to carry out repairs within 24 hours, but replacing a damaged roof tile could take a week or two and investigating then fixing rising damp, much longer. You may need to contact your landlord or agent again if they don’t take action after you report a repair, but if repairs are still not completed within a reasonable time, you can contact the Housing Enforcement team using the report form on our repairs page.

Alternatively, where the only issues affecting your property are damp and mould, you may contact us using our dedicated Damp and Mould telephone number (01302) 737996.

St Leger Homes Tenants

St Leger Homes of Doncaster are firmly committed to providing good quality, safe and decent homes ensuring that any damp or mould issues identified within the properties are robustly addressed in a reasonable timescale with the collaboration and support of their tenants.

St Leger Homes recognise the wider impact damp, mould and condensation within a home can have on tenants, and understand their responsibilities and obligations in addressing such issues when they occur. They have developed a policy to set out our commitment to tackling issues of damp and mould, demonstrating the importance they place on meeting their responsibilities and obligations. For further information and reporting issues please see Damp, Mould and Condensation - St Leger Homes

Government Guidance on Damp & Mould

The Government have recently published guidance around understanding and addressing the risk from damp and mould in rented properties. The guidance sets out the actions that can be taken by landlords and housing providers to address and reduce the risks of damp and mould in their properties.

Downloads & Resources

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Last updated: 30 October 2024 14:31:55