Condensation, damp and mould

Many properties struggle with condensation and mould. If left untreated, mould can cause long-term damage to the property, as well as having a sometimes-devastating impact on occupants’ health.

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.

This type of dampness is usually found on external walls or due to roof leaks on ceilings. It only appears because of a defect outside the home, such as missing pointing, cracked rendering, missing roof tiles or defective rainwater goods. These defects then allow water to pass from the outside to the inner surfaces. Penetrating dampness is far more noticeable following 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.

Leaks from water and waste pipes, especially in bathrooms and kitchens, are relatively common. The affected area looks and feels damp to the tough 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 pipework, such as guttering will usually find the source of the problem. Note. Black mould is rarely seen on this type of dampness as the area is usually too wet and the chemicals in a waste water leak will prevent mould growth.

This is generally 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 has no DPC. A DPC is a horizontal layer of waterproof material in the walls of a building just above ground level to stop moisture rising through the walls by capillary action. Rising damp will usually only affect basements and ground floor rooms. It will normally rise no more than 12 to 24 inches above ground level and usually leaves a ‘tide mark’ low on the wall. You may also notice white salts on the affected areas called efflorescence salts.

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 not usually be seen where there is rising damp. This is because rising dampness carries with it ground salts which prevent the growth of black mould. However secondary factors can result in conditions becoming varied.

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 home 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 poor 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

Reducing condensation and dampness

Produce Less Moisture

Ordinary daily activities produce a lot of moisture. To reduce this:

Dry clothes outdoors if possible.
Avoid drying clothes indoors or if you have to, dry them on a clothes airer in the bathroom with the door closed and either an extractor fan on or a window slightly open.
Vent tumble driers to the outside (never into the property) or buy a condensing type.
Cover pans when cooking and do not leave kettles boiling on the stove.
Do not use paraffin or gas bottle heaters. They produce large amounts of water vapour and are very expensive to run!

Heating

In cold weather, the best way to keep rooms warm and avoid condensation is to keep low background heat on all day rather than short bursts of high heat when you are in the house. Good heating controls on your radiators, an independent room thermostat and a timer will help you control the heating throughout your house and help manage heating costs.

Remove Excess Moisture

Always wipe the windows and window sills of your property every morning to remove condensation. This is especially important in the bedroom, bathroom and kitchen – just opening the window is not enough.

Insulation

Insulating and draught-proofing will help keep your property warm and save money on your heating bills.

Insulate the loft to a depth of 300mm.
Consider secondary or double glazing.
Consider cavity wall insulation or internal dry lining.
Draught-proof windows and external doors. When draughtproofing, do not block permanent ventilators or rooms requiring ventilation.

Ventilation

It’s important to remove condensation and excess moisture by ventilating rooms. You can ventilate a room without making draughts or causing it to become cold. To do this, you may only need to open the window slightly or use the trickle vent that can often be found on new windows. This allows warm moisture laden air to escape to the outside and let cool dry air into the property.

Dry cool air is actually cheaper to heat than warm moist air!

Always ventilate or open a window when using the kitchen or the bathroom and close the doors to prevent moisture in the air from spreading to other parts of the house.
Continue to ventilate these rooms for a short time after a shower, bath or cooking and keep the door closed.
Open bedroom windows for up to one hour as soon as you get up.
Clear window sills of clutter that will restrict opening the window and prevent surfaces from being wiped.
Leave space between the back of furniture and cold walls for air to circulate.
Ventilate cupboards and wardrobes and avoid overfilling them as this prevents air circulating.
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

Remember – only ventilate for an appropriate period of time (usually between 30 mins to 1 hour), don’t leave the windows open all day!

Dealing with mould

Carefully remove excess mould with a damp cloth and throw away afterwards, or if possible, use a vacuum cleaner and empty afterwards. Do not brush mould as this release’s spores into the air. Wipe down affected areas using a fungicidal wash or diluted bleach – remember always use rubber gloves and wear safety glasses. After treatment redecorate using a fungicidal paint – do not paint over using an ordinary paint as mould is likely to grow back. Dry clean clothes and shampoo carpets where necessary.

Dealing with condensation and mould growth is not easy. Only carrying out one or two of the steps may not solve your problem, you need to do as much as possible every day. Once a balance has been achieved your situation should improve over time

Homeowners

If after following the guidance you are still experiencing damp and mould in your home, you may be eligible, subject to funding, to assistance through grants and loans.

To find out more contact the Home Energy Team on 01472 326296 option 5 or email energy@nelincs.gov.uk.

Tenants

If after following the guidance on this page, you are still experiencing damp and mould in your property, you need to report your concerns to your landlord.

Should your landlord fail to engage after 14 days of you raising your complaint, and you require assistance please contact the Home Improvement Service on 01472 326296 option 3 or email homeimprovementteam@nelincs.gov.uk.

Landlords

Landlords should:

Work with their tenants to determine the cause of the problem and carry out repairs identified at the property.
After treatment, redecorate using a specialist bathroom or kitchen paint, where possible do not use wallpaper in bathrooms and kitchens. If wallpapering any area, make sure to use a good quality paste with an anti-fungicidal additive.
Provide mechanical ventilation with a humidity sensor.

If after following the guidance, your tenants are still experiencing damp and mould in your property, you may be eligible, subject to meeting qualifying criteria, to assistance through a landlord energy repayment loan.

To find out more contact the Home Energy Team on 01472 326296 option 5 or email energy@nelincs.gov.uk.