Black Mould in Homes

Black mould is a common problem for many households, especially during periods of cold weather, and can be an unpleasant nuisance that causes damage to walls, furnishings and can even pose health risks.

If you spot the signs of black mould in your property and are concerned about what could be causing the problem, it is crucial to act quickly by attempting to identify the moisture source that is causing it to grow. While wiping away black mould can remove the problem short term, generally the appearance of mould indicates a serious damp problem that may even require professional assistance.

Rentokil Property Care have been providing advice and specialist solutions for damp and mould problems for decades, and can provide you with professional solutions to safely eliminate mould and provide long term solutions for the root cause.

While DIY options may help in some cases, in others, professional chemical cleans, ventilation improvements and treatments to increase the thermal efficiency of a property may be required. A damp survey carried out by a CSRT or CSTDB qualified professional surveyor can help provide you with answers if you are concerned about black mould in your home.

Black mould is a species of mould that thrive in damp and humid environments, typically affecting basements, north facing external walls and areas where moisture is produced, like bathrooms and kitchens. While black mould may often appear as black patches, it can also be dark green and has a distinct slimy and wet feel. It may first appear as small black specks in the corner of window frames, but over time it can thrive in damp places with poor ventilation. It will grow on numerous surfaces, thriving on drywall, wallpaper, leather goods and timber.

If you notice the black mould issue getting larger in size it may indicate the mould is actively growing. The black mould will continue to grow until the source of the moisture providing conditions for growth has been removed.

Black mould is often an indicator of a condensation problem, but can sometimes occur because of penetrating damp causing a cold bridge, which makes identifying the root cause important. While damp and black mould can lead to unpleasant musty smells, it can also create an unpleasant internal environment and cause health problems for occupants.

Black mould spores are all around us in the atmosphere, and will germinate on damp surfaces in the right conditions.

Mould is a general term for any type of fine cotton-wool like surface fungus, while black mould specifically refers to types of mould that are black or dark green in colour. The variety of mould known as Stachybotrys chartarum is often labelled as black mould. Moulds of different colours will thrive in damp spaces with a lack of ventilation, and all will cause unpleasant smells, and potential health issues for the young, elderly and those who suffer from allergies.

Black mould is a term most people use, however not all mould is black, it can also be green, brown, red, yellow, grey or white.  All can cause health issues for some susceptible people.

The main cause of black mould in the home is the presence of excess moisture in the atmosphere, known as humidity. When moisture laden air cools, it condenses on surfaces and over time this creates the conditions for mould spores to germinate. While other issues like leaking pipes and penetrating damp can cause mould to form, the most common cause of mould growth is a lack of ventilation to allow trapped humid air to escape a property.

Daily activities like cooking and cleaning will produce moisture vapour that circulates around the home. Unless it is removed through ventilation in the form of open windows, window trickle vents, extractor fans or PIV units, over time the moisture laden air will cool and condense on cold surfaces.

This means that to prevent black mould from forming you either need to increase ventilation and air flow, remove cold spots on walls and ceilings or increase the temperature of the air inside the home. As the main cause of a black mould problem is not always clear, a damp survey can provide answers and solutions from a trained and qualified professional surveyor.

These are some common signs that you have a black mould problem in your property, which need to be addressed as soon as possible.

Black mould and condensation can form in hidden voids, roof spaces, behind large furniture and in inaccessible areas. You may require a professional damp survey in order to fully understand the extent of the issue.

While black mould and condensation are very common in the UK, the extent of the problem is unique to each property, so the action taken will depend on several factors. Often small changes to the way you produce moisture in the home can help reduce condensation, while isolated areas of black mould around window frames can be wiped away. But if the problem persists and DIY solutions do not work, you may require a professional damp survey to fully assess the mould problem in your property.

Improving ventilation is one of the most effective long-term solutions to prevent mould caused by condensation - this can be done through using extractor fans, the installation of PIV units or opening window trickle vents.

You may notice that black mould is forming in specific patterns on the ceiling, and this could indicate a problem with missing loft insulation. You may require insulation being topped up, or being replaced altogether.

Sometimes external walls are affected by cold bridging, and this causes cold spots which humid air will condense on. Thermal plastering and anti-condensation paints can be used to increase the thermal efficiency of walls, helping remove cold spots where more traditional insulation methods are not suitable for solid wall properties..

Sometimes black mould can be prevented by increasing air flow by moving furniture away from walls, especially large furniture like the headboards of beds, large cupboards and wardrobes. Bay windows are common areas affected by black mould because of a lack of air circulation, particularly behind long curtains or large items of furniture.

A CSRT or CSTDB qualified surveyor from Rentokil Property Care can provide you with answers on why you have black mould forming in your property, and can offer advice and treatment options for a long term solution.

Studies have shown that exposure to all forms of mould can cause health risks and create an unpleasant indoor environment for occupants due to the low air quality within a property. While symptoms range from sore eyes to coughing and sneezing, difficulty breathing and in some cases can trigger asthma attacks.

People who suffer from specific allergies or asthma may suffer from attacks or difficulty breathing. Over time symptoms can worsen and prolonged exposure is linked to respiratory problems in those with weakened immune systems.

While damp and humid conditions caused by condensation and black mould growth create an unpleasant atmosphere to live in, the moist air can also contain dust mite allergens and other organic compounds.

Legislation in the UK identifies damp and mould as a ‘category one’ hazard, while Awaab’s Law and the Social Housing (Regulation) Act was introduced after the tragic death of Awaab Ishak in December 2020 from a severe respiratory infection caused by prolonged exposure to damp and mould in his home. This legislation highlights the risks associated with damp and mould problems in homes in the UK, and the need for advice and solutions from qualified professionals within strict time frames.

There are various ways to eliminate a black mould problem in a property, ranging from DIY fixes, professional cleans to ventilation improvements and improving the thermal efficiency of the property through thermal plastering, anti-condensation paints and insulation improvements.

If you are concerned about a black mould problem in your property, you may require professional assistance. Rentokil Property Care will be able to provide you with a damp survey, giving you the peace of mind that comes with a professional inspection of your property.

Rentokil Property Care are experts in damp and condensation solutions, and have been offering professional damp surveys for black mould for decades. We provide help to homeowners, social housing providers and commercial clients across the country with solutions for condensation problems.

Our CSRT and CSTDB qualified surveyors will take the time to thoroughly investigate your property, while using a range of methods and specialist tools to identify the root cause of the problem. This will include the use of thermal imaging cameras to identify cold spots, checking the ventilation requirements, and will provide you with guidance to effectively control excessive moisture.

All findings will be detailed in an easy to read survey report, along with recommendations for treatments where necessary. This may include thermal improvements to walls, increased ventilation or insulation top ups.

Rentokil Property Care has been working in peoples homes and businesses for over 70 years, correctly identifying property issues and providing long term solutions.

We are experts in property preservation, and can provide you with personalised advice for the black mould problem affecting your property.