The Relationship Between Mould and Moisture, including Relative Humidity

Do you have a musty smell on your carpets, walls, or ceilings?

You could be dealing with a mould problem in your home.

Apart from being destructive and unsightly, mould can damage fabrics and furnishings and what’s more, it can lead to respiratory and other significant health issues.

In this article, we’ll look at the relationship between mould and moisture, including relative humidity. We also explore the best ways to prevent a mould problem.

What is Mould?

Mould is naturally occurring in our environment.  It breaks down organic materials in the outdoor environment. However, you do not want mould growing inside your home.

For mould growth to begin within a building, sufficient moisture must be present. This moisture can include an undetected water leak, water damage not corrected within 72 hours, or a flooding event or in some cases, extended periods where relative humidity exceeds 60% and a food source such as dust, carpets, wallpapers and clothing and other items are present.

Essentially mould can become a problem when spores land in a damp or wet area and begin to reproduce.

How Does High Humidity and Moisture Encourage Mould Growth?

Mould loves wet conditions and thrives where there is constant moisture.

These tiny spores move through the air and multiply in damp areas like basements, attics, kitchens and bathrooms, especially when those areas are not ventilated.

Condensation can cause excess moisture indoors. Condensation occurs when the air indoors can’t hold any extra moisture, and the water vapour in the air, changes from vapour to liquid.

Drying clothes indoors, showering, and cooking without enough ventilation can all lead to excess moisture. In addition, droplets on walls, windowsills, and mirrors indicate a moisture problem.

Over time, failure to address a moisture problem can lead to mould growth when spores settle and there is sufficient moisture for the mould to develop.

If you live in areas where humidity levels are high, this excess moisture outside can affect the humidity inside. Humidity levels of 60% RH or higher form the best conditions for mould to grow. When high humidity and moisture inside a room combine, mould can develop.

Although mould thrives in warm conditions, moisture is important for its growth.

Areas like bathrooms and kitchens are more prone to mould as this is where humidity is usually highest. Nonetheless, you may still notice mould formation in other rooms if they also have a moisture problem.

Living in a mould contaminated home can affect your physical well-being. For example, some people feel exhausted, while others may experience constant headaches.

People living with respiratory problems may have a difficult time, and their symptoms can worsen.  That’s why you should remediate a mould issue and make specific changes to prevent future mould outbreaks.

Ventilation reduces Moisture and Mould Growth

A lack of ventilation is one of the common causes of excess moisture and humidity problems in most homes. Things like showering and cooking add moisture to a room, and when moisture doesn’t have an outlet, it builds up in the air and condenses onto hard surfaces, leading to mould growth.

Some of the signs of poor ventilation include:

• Musty odours that don’t dissipate
• Frosted-looking shower doors and glass windows
• Rust staining on metal pipes
• Heat build-up that doesn’t dissipate
• Mould growth and appearance on wood, fabric surfaces, or walls

Proper ventilation can help reduce these problems.

How Does Ventilation Reduce Mould?

Ventilation prevents the formation of mould by ensuring any moisture and humid air gets an outlet. Proper airflow cuts back on moisture and dries damp areas of your home quickly.

Some of the methods that can help ventilate a building include:

• Natural Ventilation

Natural ventilation involves wind and thermal buoyancy driving outdoor air through doors, windows, chimneys, and wind towers.

Building design, human behaviour, and climate play a role in how natural ventilation works.

A properly designed house needs to have in-built openings like windows, doors, wind towers, solar chimneys, and more.

For example, you can open windows to allow fresh air in and moisture out.  Leave the window vents open and leave internal doors open when you’re not cooking or  showering to let air flow freely.

• Mechanical Ventilation

Sometimes natural ventilation is impractical or insufficient. In this case, you need mechanical ventilation.

Mechanical ventilation involves the use of mechanical fans.

These fans can be installed directly on walls or in windows. Some people also prefer installing air ducts for supplying air into a room or exhausting air from a room.

In humid and warm climates, infiltration is used to prevent or reduce interstitial condensation when moist, warm air from the inside penetrates the floor, roof, or wall and meets a damp area. Positive pressure mechanical ventilation helps to curb this problem. In this case, the air is leaked out through envelope leakages.

However, exfiltration is required to handle the condensation in a cold climate, which involves negative pressure ventilation. That consists in sucking air from outside to prevent or reduce interstitial condensation.

• Hybrid Ventilation

Hybrid ventilation comes in handy when the natural ventilation flow rate is too slow such as in your subfloor. This method uses exhaust fans to increase ventilation rates in places housing individuals with airborne infections.

The number and size of exhaust fans will depend on the required ventilation rate.

Note that using hybrid ventilation requires extra care as the exhaust fans need to be tested and measured before use. In addition, installation should be done where air can be exhausted directly to the outside through the roof or wall.

Other Tools You Can Use to Get Rid of Moisture

Mould prevention starts with getting rid of any moisture that may provide a breeding ground.

Some of the other tools you can use to get rid of moisture include:

• A Dehumidifier

A dehumidifier will come in handy if you live in an area that experiences a humidity problem. The tool allows the regulation of relative humidity in a room.

However, if you have a big room, the system will regulate the humidity levels more, which means incurring extra utility bills.

• DampRid

DampRid is meant to remove moisture from a small area like a bedroom. The product uses calcium chloride to remove moisture from the air, hardens, and becomes a solid mass.

Although DampRid is easy to use and affordable, it only works for small spaces and requires replacements. In addition, it’s not a permanent solution to remove moisture from your home.

Final Thoughts

High humidity levels and moisture contribute to mould formation. While things like DampRid and dehumidifiers can address the problem of moisture and humidity, they are not long-term and permanent solutions.

Ventilation is the only way to allow naturally occurring moisture and humidity in your kitchen, bathrooms, and laundry area to evaporate before mould spores grow.

Contact PureProtect at 1800 664 662