Ultimate Guide to Understanding, Preventing, and Removing Mould

Aug 19, 2023

Firstly, What on Earth is Mould and Mildew?

Learn how to get rid of mould with our comprehensive guide below.

Mould and mildew are both forms of fungi that are commonly found in homes. Mould is a type of fungus that consists of multiple similar nuclei and develops in black or green patches. The fungus breaks in underneath the surface of the affected material. On the other hand, mildew is a specific type of mould with a flat growth pattern, and it remains on the surface only, which makes it easier to remove.

Why do mould and mildew occur on walls, ceilings and bathrooms?

Moulds and mildew are considered part of the natural environment, and they reproduce with the help of tiny spores that float through the indoor and outdoor air and cannot be seen with the naked eye. Mould usually starts to grow inside the home, particularly on walls when mould spores land on surfaces that are either wet or have moisture.

Is mould removal easy?

It’s tough to get rid of mould and mildew as they spread very easily, and are capable of living on various types of surfaces. However, it is important to remove these fungi before they cause health problems and structural damage to your property.

How does mould affect your health?

You will most likely experience allergic reactions, such as sneezing, throat irritation, a runny nose, and skin rash and irritation if you have uncontrolled mould in your house. This is because these microorganisms are known to produce allergens as well as irritants and toxic substances. If mould and mildew are not controlled, they may even cause permanent lung damage in some individuals.

Keep reading to find out how you can remove mould on your walls.

Why do I have mould on my walls, ceiling and bathrooms?

We all know that the cause for mould growth in the kitchen and bathroom is constant humidity from steam, whereas most of us are unaware of the reasons that contribute to the growth of mould in bedrooms. Below is the list of possible causes of mould growth on the walls in your bedroom:


Humidity is the number one cause behind the growth of mould on the walls of the bedroom. If you are living in a humid area, your walls are vulnerable to fungi. Humidity can also be caused due to poor ventilation in the bedroom.


Condensation is a natural phenomenon that usually occurs on cooler walls than the air present inside the house. The water present in the air can experience a fall in temperature when it gets in touch with the walls. This temperature drop causes a state of change into a liquid. If the liquid stays on the walls for a long period, the walls become an ideal surface for mould growth.

Water Leaks:

This is the 3rd most common reason contributing to mould growth on the bedroom walls. If there is an internal leakage of pipes, it is most likely that the water will make its way into the wall, increasing its moisture. The moisture builds up with time and becomes an ideal spot for mould growth.

Signs of mould growing in your walls and ceilings:

Moulds usually start with just a tiny spot, but it grows rapidly. The colour of mould can be black or white or greenish, and its appearance is mostly powdery, cottony, or velvety. Following are the signs of mould growth:

  • It has a stale, earthy odour.
  • It must be near some source of moisture where the light is not much.
  • The material on which it is growing is likely to experience warping, peeling, or cracking.
  • If you put a drop of bleach on it, its colour will be lightened within a minute or two.
  • Mould tends to grow with time as opposed to the dirt or old stains on the surface.
  • Equipment you’ll need to get rid of mould from walls and ceilings:

The following equipment might be required during and after the removal process:

  1. Scaffolding: A ladder or scaffolding is required to reach areas that are high such as ceilings.
  2. Vacuum: It is required to vacuum the surface before and after the process of mould removal.
  3. Dehumidifier: Once the mould is removed, it is recommended to use a dehumidifier to remove any moisture in the air.
  4. Fans: Fans can be beneficial in letting the air out of the room; the air may contain any mould spores. Fans are also helpful to dry any wet areas.

Materials you will need to get rid of mould:

The following materials are required to remove mould from the walls and ceilings:

  1. Stiff bristled brush.
  2. Cloth
  3. Chlorine bleach
  4. Water
  5. Wear protective clothing

It is advised to wear protective clothing such as a plastic biohazard suit before the mould removal process starts. Also, do not forget to wear masks, gloves, and goggles to protect your hands, face, and eyes.

How to get rid of mould in 6 easy steps:

Step 1: The first step is to wear protective gear and clothing.

Step 2: The second step is making a solution of chlorine bleach and water. The solution must have three parts of water and one part of chlorine. You can alternatively use a household detergent that has bleach as an active ingredient.

Step 3: With the help of a stiff-bristled brush dipped in bleach water, thoroughly scrub the area of mould growth.

Step 4: Properly rinse the area with the help of cloth and water.

Step 5: Let the area completely dry with the help of fans.

Step 6: Use a dehumidifier to remove excess moisture from the air and help maintain the ideal humidity level.

Does bleach kill mould?

Bleach can be used to remove traces of mould on hard and impermeable surfaces such as tubs or tile. On the other hand, the mould growth on porous surfaces such as wood cannot be killed by bleach because mould penetrates deep into porous surfaces. Therefore, even if you use bleach to wipe the mould away, it will grow again from underneath the surface in a minimal period.

Do commercial mould cleaning products get rid of mould?

Yes, commercial mould cleaning products work as they consist of chemical agents that kill microorganisms and can restrain the growth of mould. In addition, commercial products are specifically made to remove mould from porous surfaces. However, they are not meant to remove the stains that mould build-up may have left behind.

When to call in the professional mould removalists?

It is advised to call a professional to remove mould in the following scenarios:

  • When you cannot figure out the mould growth or moisture problem, you can smell mould.
  • When there is a huge amount of mould that cannot be treated easily.
  • When there are people in the home who have serious health problems such as asthma or allergy or there are people who have a fragile immune system. Mould can cause serious health issues in those people, so it is advised to call a professional in those situations.
  • If other hazardous materials such as asbestos or lead are most likely to get disturbed upon removing the mould.
  • If the excessive moisture has led to structural problems.

How to prevent mould from growing back on your walls and ceilings?

It is essential to take the precautions necessary to avoid mould from coming back or growing on your walls, ceilings and bathrooms.

  • Make it a habit to open windows daily for a certain amount of time to increase the ventilation. Additionally, make sure that your air vents are not blocked.
  • If there are no windows, then it is advised to turn up the thermostat for ventilation.
  • Fix any leakages as soon as they are discovered.
  • Do not dry laundry inside your house; however, if it isn’t feasible, you should consider investing in a dehumidifier.

How does a dehumidifier get rid of mould?

Dehumidifiers are perfect for preventing mould from growing in your home. The mechanism used by the dehumidifier is pretty simple and below are the 5 five steps that best describe the mechanism:

  1. The dehumidifier comes with a fan that pulls in the air from the bedroom.
  2. The dehumidifier then cools the air inside to condense moisture into water.
  3. The water is then separated from the dried air, and the separated water is put in a separate segment.
  4. The dried air, which now has very little moisture, is re-released into the room.
  5. Once the desired humidity level is achieved, the dehumidifier will stop, or it will also stop if the water section is full and cannot hold any more water.

How to use a dehumidifier for mould removal:

Before going into the details of using a dehumidifier, please keep in mind that different dehumidifiers have different capacities, which is why it is essential to buy the dehumidifier by the size and humidity level of your room. Once you have the dehumidifier, follow the steps to use it:

  1. Locate the dampest area of your house and set up the dehumidifier there. Each dehumidifier comes with a manual, which would help you to set it up.
  2. Once the dehumidifier is set up, it is time to set the ideal level of humidity that you want to achieve. The ideal humidity level is considered to be somewhere between 40% and 60%.
  3. At this point, it is important to note that normally the dehumidifier removes more humidity in the first few cycles than in later cycles. This is because, in the beginning, it will remove excess water that has already built up in the air over some time, while once the excess water is removed, it will remove less amount of water required to maintain the ideal humidity level.

Frequently Asked Questions about Understanding, Preventing, and Removing Mould and Mildew

1. What is the difference between mould and mildew?

Mould consists of multiple nuclei and develops in patches underneath surfaces, while mildew is a flat mould type that remains on surfaces.

2. How do mould and mildew occur in homes?

They are naturally present and grow indoors when spores land on wet or moist surfaces.

3. Are mould and mildew easy to remove?

Removing them can be difficult as they spread easily and need to be removed to prevent health issues and property damage.

4. What health problems can mould cause?

Exposure can lead to allergies, sneezing, throat irritation, and even permanent lung damage.

5. Why do I have mould in certain areas of my home?

Humidity, poor ventilation, and water leaks contribute to mould growth in areas like walls, ceilings, and bathrooms.

6. How can I identify signs of mould growth?

Look for discolored patches, musty odors, and warping or peeling of materials.

7. What equipment is needed to remove mould?

You might need a ladder, vacuum, dehumidifier, fans, stiff-bristled brush, cloth, chlorine bleach, and protective clothing.

8. Can bleach effectively kill mould?

Bleach can remove mould on hard surfaces, but it might not work on porous surfaces where mould penetrates deeply.

9. Do commercial mould cleaning products work?

Yes, they can be effective in killing mould and preventing its growth, especially on porous surfaces.

10. When should I call professional mould removalists?

Call professionals if mould growth is extensive, you have health issues, or hazardous materials are present.

11. How can I prevent mould from returning?

Ensure proper ventilation, fix leaks promptly, and avoid drying laundry indoors. A dehumidifier can help maintain optimal humidity levels.

12. Can a dehumidifier prevent mould growth?

Yes, dehumidifiers reduce moisture levels in the air, making it less conducive for mould to grow.

13. How do I use a dehumidifier for mould removal?

Place it in the dampest area, set the desired humidity level, and let it cycle to maintain the right moisture balance.

14. Is it possible to remove mould stains?

Commercial mould cleaning products can help with stains, but prevention is key to avoiding future staining.

15. Why is proper ventilation important in mould prevention?

Adequate ventilation helps control moisture levels, preventing conditions that favour mould growth.

Miracle Maid

Miracle Maid is a highly-rated house cleaning services company in Sydney, NSW. We offer tailored cleaning for homes and apartments. One-time and repeat cleaning services.

You're 60 Seconds From A Clean Home

Get a quote & book your cleaning service online.