25th November 2022

Black mould is a direct effect of condensation and is a common problem in households with poor ventilation and excess moisture in the air. Black mould needs a lot of moisture to germinate and grow, humid damp dark areas in a house increase this likelihood.  Black mould is generally harmless and not all black moulds are toxic. The Stachybotrys chartarum strain can have a serious impact on health causing respiratory symptoms such as a cough, sinusitis, nose bleeds, headaches, fatigue or fever.

What causes black mould growth?
One of the main causes of black mould growth is the excess moisture created from poor ventilation alongside everyday living. On average, one sleeping person adds half a pint of water to the air overnight and at twice that rate when active during the day! Households often create a large quantity of water vapour through everyday activities such as cooking, showering, running baths and even steam ironing. This moisture laden air if not ventilated will cause mould growth to occur. The water vapour when it comes into contact with a surface that is colder than itself will leave water droplets on that surface. Once this water comes into contact with materials such as wallpaper or curtains, it will feel damp and over time a damp odour will occur.  

Other factors that may cause black mould growth could be rising damp which may be due to a plumbing leak, often from the water pipes under your shower and bath or from behind the walls. Penetrating damp however enters the wall above the damp proof course and is usually caused by defective roofing, guttering, rendering, brickwork, doors or windows.

How to spot signs of black mould
In its inactive state black mould will be powdery and dry in appearance but when active the mould will have a black or dark green slimy appearance. Black mould will often appear on window sills, ceilings and walls of a property. Mould may not always be visible and can be present behind wallpaper, under floorboards or develop in the loft space. Further damage to furniture and fabrics may also occur.  A damp musty odour maybe present or the occupants of the property may develop symptoms such as coughing which can be a sign of an allergic reaction to the mould.

How to prevent black mould
To prevent black mould, ensure air vents are not blocked, open windows regularly, use trickle vents and extractor fans if fitted. Cross ventilate your home by allowing drier air through your home daily by opening an upstairs window a little and downstairs too. For those living in a flat, open diagonally opposite windows for approximately 30 minutes daily. When cooking ensure pan lids are on and turn the heat down once the water has boiled, using the minimum amount of water necessary.

Hang your washing outside to dry or in the bathroom with the door closed, the window slightly open and the extractor fan on if you have one.  Also avoid drying your clothes on radiators or in front of a fire.

When bathing, run the cold water first then add the hot when filling your bathtub, this will drastically reduce the amount of steam created. If you use a non-condensing  tumble dryer, make sure it is vented to the outside of the property. Dry windows and window sills every morning, also wiping down wet surfaces in the bathroom and kitchen will help reduce condensation.

Avoid restricting the flow of air by keeping a small gap between large pieces of furniture and the walls, placing furniture like wardrobes against internal walls is recommended. Keeping a constant temperature in your home will help control condensation, so it is better to have a constant level of heat throughout your home, ideally between 17°C and 21°C. Condensation is made worse in the rooms that aren’t heated, if an adjacent room is heated to a high temperature. 

How to deal with black mould 
Protective gear should be worn throughout the mould removal process. Clean any walls, ceilings and paintwork affected by mould with a fungicidal cleaner following the instructions carefully. Ensure that the mould and mildew remover carries a Health & Safety Executive (HSE) approved number.

In the kitchen, cabinets can be cleaned using a homemade solution with equal parts water and detergent in a spray bottle. Scrub with a small brush or old toothbrush if necessary to remove the black mould.

Bathroom tiles, sinks and bathtubs affected with mould can be sprayed with the cleaning solution and wiped away with a sponge. Again, trapped mould can be scrubbed with an old toothbrush. Change your shower curtain regularly to eliminate dormant spores. In other areas of the home regularly clean organic materials such as wooden surfaces, wash fabrics, and replace items made from cardboard as mould feeds on these organic materials.

After treatment has been completed you can use anti-condensation paint which maintains the surface temperature on walls. Removing black mould effectively and following some of the lifestyle changes explained above should prevent condensation and further black mould from reappearing. If however the problem is more severe and widespread then treating the cause of the damp problem may require calling in a specialist.

The Dean & Co Team
If you would like to contact us please call on   or email: sales@dean-property.co.uk