In this expert guide the air quality specialists at WTS consider the most common types of mould found in houses, offices and other workplaces, which ones can be dangerous and how they affect the health and wellbeing of building occupants.

The guide looks at the importance of being able to spot the different mould types, and the general classifications of allergenic, pathogenic and toxigenic moulds.

It examines twelve of the most common types and explains how to recognise them, tells you which ones can be dangerous and describes the different health effects of exposure to each.

The guide concludes with a look at processes for mould testing and remediation and what they involve.

What are the common types of mould?

There are lots of different types of mould, however, among them there are a number of common strains which are found more often in homes, offices and other workplace environments and these include:

Acremonium
Alternaria
Aspergillus
Aureobasidium
Chaetomium
Cladosporium
Fusarium
Mucor
Penicillin
Stachybotrys (Black Mould)
Trichoderma
Ulocladium

Where does mould grow?

Most of us understand that the presence of mould can be a potentially serious health hazard when it’s allowed to grow in our homes and workplaces.

All types of mould love wet, dark environments where the ambient temperatures tend to lie between 15 ^oC and 25 ^oC.

Mould is incredibly adaptive and can grow anywhere – in the home, office and other work environments… it can even grow inside cars or other places where you will spend time with family, friends and work colleagues.

Recognising the different types of mould in homes, offices and the workplace

Being able to recognise the different types of mould, understand why it can be dangerous and know how to deal with it are all important skills.

In most cases, mould is a minor issue which businesses and homeowners can tackle themselves with off-the-shelf cleaning products bought from the supermarket.

Sometimes however, the problem is severe enough to require intervention from the professionals such as the mould specialists at WTS.

Learn more about mould testing

How does mould affect your health?

Unfortunately, some types of mould can be dangerous and have a serious impact on human health.

Mould particularly affects the elderly, young children, pregnant women, people with respiratory issues and anyone with an underlying health condition.

Worldwide, there has been extensive research into the links between mould exposure and human health… some of the main health issues identified include:

Mould Sensitivity
Just as with other substances, some people are more sensitive to mould exposure than others.
A mould sensitivity or allergy can also develop over time. Symptoms may be mild or more severe, and can include congestion, coughing, sneezing, shortness of breath, watering or sore eyes, and irritation on the skin or headaches.
Existing Health Conditions
If you have someone in your family living with lung conditions such as asthma, COPD or other immune system problems, then they are more likely to develop problems associated with mould. In these types of patients, mould can cause lung infections of varying degrees of severity.
Breathing Problems
Exposure to mould can also cause breathing problems in some people.
These could be mild problems with coughing or wheezing, or asthma-like symptoms. This is particularly a concern for children, as they may go on to develop asthma as they grow.
Existing asthma sufferers can also find that their symptoms can get much worse when exposed to mould.
Mycotoxins
Some types of mould release mycotoxins, which are absorbed by the skin or inhaled in to the lungs. In the most serious cases, exposure to mycotoxins can cause scarring in the lungs (pulmonary fibrosis), cancer, and problems with the liver or kidneys, complications in pregnancy or bleeding in the lungs.

Getting rid of mould from homes and workplaces

Often, getting rid of mould inside the home or workplace isn’t a straightforward matter.

To start it can be hard to work out what type of mould you are dealing with, and the removal process itself can be dangerous especially if suitable precautions are not taken.

Mould removal professionals have access to specialist equipment which can get rid of all mould in your house or workplace and more importantly, stop it coming back.

What are the common types mould?

All types of mould are a type of fungus, and it’s found in almost every environment on earth.

Awareness of the health issues caused by mould has been growing over recent years.

Current estimates of the total number of species of mould are now in the tens of thousands.

Luckily many of these species of mould are not harmful to human health, but others can be very dangerous indeed.

Identifying which type of mould you are dealing with

The first step in dealing with a mould problem at home or in the workplace is to work out what sort of mould problem you have… and each type of mould is different.

It’s also worth being aware of what rooms or internal areas in your house, office or workplace are more likely to experience mould growth, and check these areas regularly for any signs.

Mould is most commonly found in basements, bathrooms, attics, under floor, in service voids and around windows.

Moulds which can be harmful to humans are classed into three groups: allergenic, pathogenic and toxigenic.

Allergenic
Allergenic moulds are the types of mould which can cause allergic reactions in people who are sensitive.
Pathogenic
Pathogenic moulds can cause health problems in people with underlying medical conditions.
Toxigenic
Toxigenic moulds are the really dangerous types of toxic mould which can lead to serious or life-threatening health conditions.

Common types of mould and what they look like?

Despite there being thousands of different types of mould, there are several common strains which are found more often.

The following guide should help you identify the main types of mould in order to work out the best way of tackling them.

Acremonium

Acremonium is a type of mould which falls into the toxigenic category and can cause serious health conditions.

Over time, the appearance of this type of toxic mould can change.

In the early stages it appears as a small, damp mould and over time it becomes powdery.

It is usually pink, orange, grey or white.

The most common places to find acremonium is in areas of high condensation, such as around window seals, or in humidifier or air conditioning equipment.

Acremonium is one of most dangerous types of mould and might lead to disorders in the immune system, bone marrow or other internal organs.

This type of mould is also a carcinogen and can affect brain function too.

It will grow and spread over time, so if it is detected, it should be professionally treated as soon as possible.

Alternaria

Alternaria is considered to be the world’s most common allergenic mould.

It shows itself as a green or brown mould, which has a velvety texture.

It can grow anywhere there is dampness and is most commonly found around the bath, shower tray or underneath a dripping sink.

If you have had water damage, a leak, or flood then Alternaria might grow as the home begins to dry out.

Alternaria can cause symptoms which can be confused with asthma.

It’s quick to spread, and needs prompt action to tackle it before the problem grows out of control.

Aspergillus

Aspergillus is a very common fungus, and it is the spores in the air which can cause problems in humans.

There are over 180 different types of this fungus, so it can vary in colour and appearance.

Aspergillus’ effects are generally mild, but can also become more toxic in certain situations.

In some patients, it can cause lung infections, inflammation of the lungs or asthma attacks.

Aureobasidium

Aureobasidium usually shows as a thick, black fungus which is most commonly found growing behind wallpaper or wooden surfaces around the home.

It can also be brown or pink.

The main risks associated with this species of mould is irritation of the eyes or skin.

If you think you might have Aureobasidium in the house, don’t touch it as direct contact can cause skin rashes.

Chaetomium

You’ll find Chaetomium in houses which have been flooded, or have serious problems with damp.

The mould has a texture like soft cotton, and although it starts off as white, it then progresses through grey, brown and eventually to black.

Another way of recognising Chaetomium is by its musty smell.

Chaetomium mould can be a cause of nail and skin infections.

In people with a compromised immune system, it could cause more serious health problems.

Typically, Chaetomium only grows in very damp places… this means that treating the mould is only half the battle – you have to fix the leaking roof, dripping tap or dampness too.

Cladosporium

Cladosporium is another type of allergenic mould.

It is an unusual mould in that it is equally happy in warm or cold environments.

Cladosporium can live quite happily in soft furnishings like carpets and curtains.

It is a dark green or brown coloured mould, with a texture resembling suede.

Coming into contact with Cladosporium can cause allergic reactions including symptoms in the nose, skin, eyes or throat.

It can also trigger asthma in sufferers.

Cladosporium should be handled with care, because of its potential to cause irritation.

Fusarium

Just like Cladosporium, the Fusarium mould isn’t fussy about warm or cold temperatures.

It thrives in areas which have been water damaged, especially in carpets, behind wallpaper or in other fabrics and soft furnishings.

This type of mould also grows on waste food, or in compost.

If you are exposed to Fusarium, it has the potential to cause a wide range of allergic symptoms as well as infections on the skin.

Fusarium spreads very quickly through the various rooms in a house, office or other workplace.

If you have spotted this mould in one location, you should check other areas of the house thoroughly as it is probably elsewhere too.

Mucor

Mucor is an allergenic type of mould, it is often grey or off-white in colour, and grows in thick patches.

It is associated with condensation, so can often be found in old, damp carpets or in air conditioning and dehumidifier equipment.

Exposure to Mucor can cause a range of health problems, mostly affecting the lungs.

It can cause asthma symptoms, or can make existing asthma worse.

In the most serious situations, Mucor can cause a serious illness called mucormycosis.

Mucormycosis is a type of fungal infection, and it can damage the brain, lungs or sinuses.

As the health consequences of exposure to Mucor can be serious, this is one type of mould which you should leave to the professionals.

If you’re planning to tackle it yourself, you will need special equipment and protective clothing as a bare minimum.

Penicillin

Although best known as an important antibiotic, Penicillin can cause health problems too.

Penicillin has a very distinctive blue or green surface with a texture like velvet.

It commonly grows in damp conditions, and can be found in wallpaper, carpets, mattresses and ducts for air conditioning or heating.

In internal environments Penicillin fungus can spread very quickly.

Pencillin mould in your home, office or workplace can cause a range of lung conditions, especially in confined spaces.

It can cause health problems to all occupants of the space it affects, including children and pets.

Penicillin can cause inflammation in the lungs and asthma and can lead to serious illness in people with immune disorders.

If the fungus is left untreated for a longer period, it can cause sinusitis.

Pencillin mould is most commonly found in damp areas, it’s therefore very important to treat the cause of the dampness as well as trying to remove the mould.

Stachybotrys (Black mould)

Stachybotrys is the infamous “black mould” which everyone has heard of.

It is a toxigenic type of mould but can also cause people to develop allergic reactions.

Stachybotrys is a mould which is black or very dark green in colour, and is slimy to the touch.

It is most commonly found in areas where humidity remains high, typically in bathrooms but in any damp areas.

It loves to grow on wood, paper, wicker furniture, paper or cardboard.

The reason Stachybotrys has such a bad reputation is because it produces mycotoxins which can seriously affect human health.

Some of the symptoms which might indicate exposure to black mould include breathing problems, tiredness or depression.

Another common effect is aching and pain in the sinuses, or a burning feeling in your airways.

Stachybotrys or black mould is known to have a link to neurological problems in growing children, and can be particularly harmful to young babies’ lungs.

If you discover Stachybotrys in your home or at work, you should get it treated right away.

If you can, it’s usually best to move out while this toxic mould is fully removed.

Trichoderma

Trichoderma covers five different types of mould, most of which are white with green patches.

It grows very quickly and loves wet surfaces on wallpaper, carpet and any damp soft furnishings.

If you have an air conditioner or dehumidifier, you might have a particular problem with this type of mould.

Most Trichoderma fungus doesn’t cause serious health issues, but some types can cause lung and liver problems.

Trichoderma can cause damage to your home, office or workplace as well as your health as it destroys textiles, wood and paper and the resulting rot can sometimes cause serious structural issues.

It’s important to make sure you have Trichoderma dealt with professionally in order to halt the spread elsewhere in your house.

Ulocladium

Ulocladium is mainly associated with damp and water, and is usually black in colour.

It is most often found in houses or workplaces which have been flooded or which have been very damp for an extended period of time.

Finding Ulocladium growing alongside other moulds such as Stachyboyrys or Fusarium is a good indication that your property has a serious damp problem.

There are two separate sub-species of Ulocladium which can cause health problems, especially in people who have other allergies or breathing problems.

It can be difficult to identify Ulocladium as it is easily confused with other types of mould.

Get the professionals in for a proper diagnosis and advice on the best way of getting rid of Ulocladium in your home, office or workplace.

How to remove mould from homes and offices

Before you call in the mould testing and remediation experts, there are a couple of things you can try yourself if you only have very small patches of the less serious types of mould.

Get your mould tested professionally

Firstly, make sure you are aware of all the type of mould problems in the property.

Check behind furniture, peel away wallpaper, check the attic and the basement and use a torch to peer into dark corners and other voids in the property.

Then get rid of any soft furnishings and other materials affected by mould – keeping them will only encourage the mould to spread elsewhere in your home, office or workplace.

When you’re doing this, remember to protect yourself by using gloves, face masks and protective goggles.

If the problem is too big to tackle by yourself, the professionals at WTS have various other tactics which they can use in addition to removing mouldy materials from your property and this could include:

Professional drying equipment
Mould remediation specialists can use dehumidifiers or fans to dry out the air and surfaces in the room.
Sealing Off Areas
In order to stop spores becoming airborne or spreading elsewhere in the property, most mould specialists will completely seal the affected room or rooms they are working in using polythene sheets and tape.
Negative air pressure
Using negative air pressure is a technique which means air can flow into the affected area, but not out of it. After the mould remediation specialists have completely sealed the area, they can use an air mover to stop spores spreading out of the affected room.
Fungicides
Fungicides are special chemicals which can be painted onto surfaces to kill off any remaining mould after thorough cleaning. Fungicides can also be used to treat surfaces which can’t be cleaned using more conventional methods.
Repair & Redecorate
Once mould remediation contractors have finished removing the mould and treating it with fungicide, you might need to re-plaster, replace flooring, fit new carpets and decorate.

As there are so many different types of mould, and so many potential health issues, it makes sense to get the professionals in to tackle the problem.

It’s important to remember that a serious mould problem can’t be tackled on your own, we recommend that you get the experts at WTS in to get rid of it for you.

Specialist mould testing and remediation solutions

WTS offer a comprehensive range of mould testing and remediation solutions to support business owners, landlords and property managers, health and safety professionals, facilities management specialists and home owners.

Our mould experts can provide advice and support to develop the most appropriate strategies for the identification, investigation and remediation of mould problems in homes, offices and other workplaces.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained technicians, in-field specialists and consultants we can offer professional, cost effective environmental solutions throughout the UK and internationally.

Contact us today to learn how our mould testing and remediation solutions can help keep you, your staff, loved ones and other people safe from exposure to mould, spores and other indoor air pollutants.