Introduction

A warm, secure, decent home is something everyone deserves, but many people globally are living in homes that have damp areas and develop mould. It has been estimated to be present in 10-50% of homes across Europe, North America, Australia and other countries such as Japan and India. Locations such as those with higher levels of humidity or those near coastal regions have a higher risk of developing dampness and mould.¹ Dampness and mould development have been known to cause negative health effects such as respiratory issues and, especially, trigger allergic reactions.^2,3,4 Therefore, prevention of mould development is important, as well as understanding the safe methods of removing mould from homes without causing further allergic reactions and respiratory issues. To find out more information on these methods, continue reading below. 

Understanding mould and its health effects

High levels of moisture can cause dampness in/on the walls, ceilings and floors of your home.¹ After some time, damp areas may produce a musty smell, and you may notice fuzzy or slimy white, black or green patches on the wall. This is mould, a type of fungus, that takes advantage of the damp conditions and organic building and furniture material to grow and survive.

Common types of mould species that grow indoors include Aspergillus, Penicillium, Cladosporium, Stachybotrys and Alternaria species.^3,4 These species can produce allergens, toxins, irritants and mould spores which spread throughout the home, and can be breathed in by the residents of that home, causing harmful health effects, especially affecting their airways and the lungs.² (EPA)

Common general health symptoms associated with mould exposure include coughing, wheezing and difficulty breathing. However, those with pre-existing conditions such as allergies and respiratory conditions, as well as those with weakened immune systems, are at a higher risk of developing more severe symptoms. Common allergy symptoms such as sneezing, itchy red eyes or skin rashes can be present. Airway infections such as aspergillosis or worsening of allergic airway diseases, including asthma, bronchitis, rhinitis or even chronic obstructive pulmonary disease (COPD) can occur.^2,3,4 (EPA) Allergic bronchopulmonary aspergillosis is a rare, severe case of both an allergic and an inflammatory response in the lungs that can also develop with mould exposure.³ 

Signs of mould infestation in the home

As mentioned previously, visible signs of mould infestation include potentially fuzzy or slimy black, green or white spots/patches of discolouration around the home. Damp areas will also typically present with a musty odour. Rooms with a build-up of high moisture levels, such as bathrooms (e.g. when showering) and kitchens (e.g. when cooking), are more likely to develop mould. Mould can develop on walls, ceilings and floors, but also in hidden areas such as behind walls, in heating, ventilation and air conditioning (HVAC) systems, under carpets and behind/on furniture. (EPA) Humidity meters are useful to keep an eye on levels and detect areas of high moisture where there is a risk of mould development.⁵ Mould test kits can then be used in those high moisture areas to detect mould development. Mould test services can be called to get an expert's diagnosis on mould development, where they can test the mould in the lab to give specific information, such as the type and severity of the infestation. An accurate, detailed diagnosis is useful for a targeted removal plan. 

Preparing for mould removal: safety first

So, how can you safely remove the mould from your home without it affecting your health any further? The first consideration should always be safety. Depending on the severity and type of mould present, you should consider whether it is safer to handle this yourself with any DIY treatments or safer to call a professional service that can help with the removal. Professionals should deal with cases such as large infestations, where the affected area is between 4-10m² or larger than 10m², or where the affected area is largely inaccessible or within an HVAC system.Besides this, if there are signs of structural building damage, getting the help of a professional would also be safer. One advantage of professional remediation services is that they can produce a case-specific assessment, solution and prevention plan regarding the specific infection within your home.

Before going ahead with the mould removal process, any person working to remove the mould should wear protective equipment such as masks, gloves, protective eyewear and coveralls to protect their clothes. This will help prevent them from being in contact with any harsh cleaning products and mould spores that are released during the removal process.² 

The area/room where the removal process is occurring should be sealed off as much as possible. Closing the doors or using plastic sheets to seal the area is important to contain the contaminants.² Windows should be kept open to allow for adequate ventilation and air movement with the outside environment, as this can also help with drying surfaces and increase evaporation of moisture.⁶ Negative pressure systems, where the air flow is contained within that sealed area rather than flowing to the surrounding areas, can help to keep harmful contaminants within the space. Air filters and purifiers can also be used to improve indoor air quality and remove harmful contaminants and mould spores from the air to prevent residents from inhaling them.

Allergy-safe mould removal 

For areas that are not excessively damaged and can be salvaged, removing as much of the fungal contamination as possible using non-toxic, hypoallergenic detergents and agents are recommended (EPA). There is evidence that bleach and some other harsh chemicals can irritate sensitive airways,⁷ so it may be best if you can avoid using these. Bleach can work on some surfaces, such as tiles and sinks, but cannot penetrate materials such as wood, fabric and drywall, so it may not be the best agent to use in these cases. Vinegar solutions, baking soda solutions, soapy water, hydrogen peroxide, or commercial mould cleaners without bleach are some examples of safe alternatives to use. For example, 1:1:1 part of baking soda, white vinegar and water solutions or 3% hydrogen peroxide solutions can be used for drywall surfaces. Fabric should be washed if it can be salvaged or thrown away if not. For materials that are severely damaged due to the mould or mould removal process should be removed. Letting the solutions sit for a while first and then using a brush or rag to scrub/wipe away the mould is advised. Dry vacuuming using HEPA vacuum cleaners can also be used and is known to have a high capture rate of small particles such as dust and mould.⁵ 

It is important to take breaks during the cleaning process to limit constant exposure to the mould and allow for areas to air and dry out. Throwing out the cleaning rags after use and replacing air filters after the removal process should also be done to prevent any remnants of the mould from being left behind. 

Other considerations for allergy-prone individuals

Regarding individuals who have allergies and other respiratory conditions, it is important to ensure the safe and efficient removal of mould. During the mould removal process, it is important to consider if the individual with allergies should be part of this or will it be best for them to avoid being present at all? Creating a “safe clean zone” during the removal process will help them avoid the affected area as much as possible. Various systems, such as air purifiers, can be placed in this zone to ensure no mould spores enter. As well as this, keeping a stock of allergy medication such as nasal sprays and antihistamine tablets will be important just in case of potential allergic reactions and flare-ups. Regularly cleaning any clothing, bedding or furnishings after the removal process can reduce the risk of mould spore exposure.

Preventing mould regrowth 

The best way to prevent mould development in your home is to ensure that indoor humidity is managed and kept at an optimum level (i.e. 40-60% humidity).⁸ Having adequate ventilation and dehumidifiers can help control the humidity levels and air quality indoors.⁹ Extractor fans can be used within rooms such as the bathroom to prevent steam build-up when showering and in the kitchen when cooking. Physical moisture barriers can be used in the walls, floors and roof to control moisture within the hidden areas and prevent structural damage. Regular inspection, cleaning and drying of these areas is essential to prevent the re-/growth of mould. 

Summary

Within homes, in areas of high humidity, dampness can occur and mould can develop, resulting in harmful health impacts, especially in individuals who have preexisting allergies, respiratory conditions and weakened immune systems. Therefore, it is important to focus on ways to safely remove mould from damp areas, including walls, floors, ceilings and other furnishings, as well as understand techniques on preventing dampness and mould from developing. The removal process should consider safety and health first, ensuring that the individuals who are part of the removal process wear protective equipment while using effective but allergy-sensitive cleaning tools, techniques and systems.

Getting professional services to diagnose, prepare treatment plans, and prevention strategies may be safer in certain circumstances rather than attempting to remove the mould yourself, so check with a professional expert beforehand. Regular inspection and cleaning, dehumidification techniques such as using extractor fans, adequate ventilation and insulation can help to prevent dampness and improve air quality indoors, to help limit the effects of indoor mould on your health and life.