Damp and mould has always been an issue in the UK due to our cold, damp climate and ageing housing stock – according to that last census most of the properties were built before 1919.

The most common form of damp is condensation. This is often caused by a lack of ventilation and heating in the home. The colder the air temperature is, the less moisture it can hold. Hence water condenses on cold surfaces such as windows and the bottom corners of walls.

The humidity inside the home will also have an effect since the temperature at which water is no longer able to exist as a gas is affected by humidity. So lots of showers, hot baths and cooking will contribute to the problem.

What is mould?

Mould usually appears as black growth in crevices, corners and around the edges of fittings, such as baths, windows, cupboards etc., but can appear anywhere.

By far the most common cause of mould growth is condensation within the property. 

What are the causes of condensation?

Over the years in our efforts to have warmer homes and reduce energy wastage we have progressively restricted the movement of air between the inside of our homes and outside. This means any moisture produced in the home tends to stay there. 

This moisture is converted into liquid (condenses) when this moist air touches a surface which is relatively cold eg:

• a window
• a corner furthest away from a radiator
• anywhere with cooler air than the rest of the room

These tend to be the areas where the black mould appears. Mould won’t grow without this moisture.

Seriously? How much moisture can we really produce?

Well, quite a lot actually. We put the following moisture into the air:

• One person’s breathing – 0.5-1 litre over 24 hours
• Cooking – 0.5 litre for each hour
• Shower – 0.25 litre for 5 minutes. 1 bath – up to 1 litre.
• Clothes washing and drying – 2 litres for every load of washing.

This all goes into the air and stays in the house unless it is removed.

This obviously increases when there are more people, people are there longer (eg at home with children rather than out), clothes are dried indoors, extractor fans are not used when cooking, or doors are left open when showering and even if people exercise in the house, substantially increasing their breathing rate and adding their sweat to the moisture in the property.

What can be done to reduce the condensation?

Here is a list of tips that we give to your residents when they move into their new home.  

1. Produce less moisture

• Cooking: Cover pans; do not leave kettles boiling;
• Washing clothes: Put washing outdoors to dry if you can, or put it in the bathroom with the door closed and the window open and/or fan on. Use the highest spin setting on the washing machine. If you have a tumble-dryer make sure you vent it to the outside (unless it is the self-condensing type). DIY kits are available for this.

2. Remove the moisture

• Ventilation: Keep a small window ajar or a trickle-ventilator open when possible. You can ventilate your home without making draughts.
• Mopping: Wipe away visible condensation and wring out the cloth into a drain.

In some properties opening windows during cold weather can attract condensation, where this happens it is necessary to be more diligent in mopping to remove the moisture.

You need much more ventilation in the kitchen and bathroom when cooking, washing up, bathing and drying clothes. If there is an extractor fan installed, then make sure this is working and used.

Close the kitchen and bathroom doors when these rooms are in use, even if your kitchen or bathroom has an extractor fan.  Doing this will help stop the moisture reaching other rooms, especially bedrooms, which are often colder and more likely to suffer condensation. The best kitchen extractors are those that push the air outside through a vent. The worst are those which simply recirculate filtered air; these remove the smell of the cooking but do not remove the moisture.

Ventilate cupboards and wardrobes. Avoid putting too many things in them, as that stops the air circulating. Leave space between the back of the wardrobe and the wall, particularly in new homes. Put floor-mounted furniture on blocks to allow air underneath. Where possible, position wardrobes and furniture against internal walls (walls which have a room on both sides) rather than against outside walls.

Make sure nothing is placed against any vents or airbricks.

3. Heat your home a little more

In cold weather, the best way to keep rooms warm enough to avoid condensation and mould is to keep low background heating on all day, even when there is no one at home. This is very important in flats and bungalows and other dwellings where the bedrooms are not above a warm living room. Thermostatic radiator valves are an excellent means of doing this, and many people believe leaving radiators on all day at a low level is more cost effective than short periods of heating at high levels. 

If you can’t afford to keep the heat on all day, it is better to spread out the periods when it is on, in particular ensuring there is a period before bedtime.

4. Cleaning of affected area

Mop up condensation whenever you see it. 

If mould appears clean with a detergent and thoroughly dry the area, then (unless it is a fabric surface) apply a 50/50 mix of bleach and water, an anti-mould preparation, and leave to dry. Once this has dried keep the area clean and dry. Test all treatments on an inconspicuous area first to ensure you do not damage the surface.

This cleaning is important as mould spores can survive long after the mould has apparently disappeared. Mould will reappear if the damp conditions continue.

What you should do as a landlord?

In short…

Make sure that you have provided the means to properly ventilate the property. Areas you should need to make sure are:

• Kitchen: extractor fans are so important to reduce the condensation from boiling pans. In older properties an airbrick is a good idea
• Bathroom: there are many different strengths of extractors . Building Regulations part F requires that any fan in the bathroom must extract at least 15 litres per second (l/s) of air from the room. Make sure the power switch is not freely available.
• Windows: make sure that the trickle vents are able to be used – classically they are painted over.

If you find there is a build up of mould the first thing to do is talk to your resident and point out  the dangers.

Our property management team are very well versed in how to deal with this type of issue before it becomes an issue. Therefore if you need a free 30 minute consultation on how we can help just book and appointment here.