How does anti-condensation paint work?

Looking for a proactive way to tackle damp and mould? Anti-condensation paint could be a great choice for your project. In this guide, we’ll delve into the science behind this product, exploring how it works to help create drier and healthier interiors.

Whether you're a building professional looking to offer cutting-edge solutions or a homeowner tired of battling moisture, understanding the mechanics of anti-condensation paint is the first step towards a damp-free future.

What is anti-condensation paint?

Anti-condensation paint is a specialised coating designed to stop the formation of condensation on surfaces. Unlike standard paints that primarily focus on aesthetics and protection against general wear and tear, anti-condensation paint incorporates unique properties that manage moisture levels on walls and ceilings. 

This type of paint typically contains microspheres or other porous materials that increase the surface area and create a thermal barrier. This barrier helps to keep the surface temperature of the coated area closer to the room temperature, reducing the chances of condensation forming.

Types of damp

Dampness in buildings can come from many different sources, including plumbing leaks, building defects, ground moisture and more. Identifying the type of damp or potential damp source is crucial for effective treatment and prevention. Anti-condensation paint primarily targets one specific type: condensation. However, it's important to differentiate it from other forms of damp to understand its appropriate application.

Penetrating damp

Penetrating damp occurs when water from the outside finds its way into a building's structure. This can be due to structural defects such as leaking roofs, damaged gutters, cracks in walls, or faulty seals around windows and doors. The dampness often appears as distinct patches that may grow after it rains. 

Anti-condensation paint will not solve penetrating damp issues as the source of the moisture is external and structural. Addressing the underlying building defects is the solution for this type of damp.

Rising damp

Rising damp is caused by groundwater being drawn up through porous building materials, such as brickwork and mortar. Typically, it appears as a band of dampness at the base of walls, often showing salt deposits and damage to skirting boards and plaster. 

Like penetrating damp, anti-condensation paint is not suitable for this and effective treatment usually involves installing a damp-proof course (DPC) or other damp-proofing techniques.

Condensation

This is where water vapour in the air turns into liquid water when it comes into contact with a cold surface. This typically happens on walls, ceilings, and windows, especially in areas with high humidity and poor ventilation, such as kitchens and bathrooms. 

Cooking, showering, and even breathing release moisture into the air, which increases humidity levels. It’s when this warm, moist air meets a cold surface that water droplets are formed. Anti-condensation paint is specifically designed to mitigate this process.

Can condensation cause Black mould?

Yes. Black mould (Stachybotrys chartarum) is a type of fungus that thrives in damp and humid environments - this includes ones with condensation. Of course, it’s a terrible sight, but it can also pose health risks, especially to people with respiratory conditions or weakened immune systems. 

Understanding the causes of black mould is essential in preventing its growth, and anti-condensation paint can play a significant role in this prevention. The main causes of black mould, including condensation, are:

1. High humidity levels

Elevated moisture content in the air provides the ideal conditions for mould spores to germinate and grow. This high humidity can be caused by poor ventilation, excessive activities that produce moisture without proper extraction, or even the drying process of new plasterwork if not managed correctly.

2. Poor ventilation

Insufficient airflow prevents the removal of moisture in the air, causing humidity to build up. Stagnant air in poorly ventilated areas, such as behind furniture or in corners, creates microclimates where condensation is more likely to occur and persist, leading to mould growth.

3. Cold surfaces

When warm, moist air comes into contact with cold surfaces, condensation forms. If this moisture persists for a long period of time, then it provides the necessary water for mould spores to spread. Areas with poor insulation are particularly susceptible to cold surfaces. 

Generally speaking, surfaces at or below the dew point temperature of the surrounding air are where condensation will occur. The dew point is the temperature to which air must be cooled at constant pressure and constant water vapour content for saturation to occur. This temperature isn't fixed and changes with the amount of moisture in the air. 

Some surfaces that are prone to condensation include:

• Single-pane windows: These readily lose heat to the outside, making their inner surfaces cold.

• Uninsulated walls: Similar to windows, they can become cold, especially in colder climates.

• Metal surfaces: Metals are also good conductors of heat and can become cold. Think of metal window frames or uninsulated metal pipes.

• Ceramic tiles in bathrooms: Especially on exterior walls, these can get cold, and the high humidity in bathrooms makes them susceptible to condensation and mould growth if not properly ventilated.

Anti-condensation paint: How does it work?

The effectiveness of anti-condensation comes from its unique formulation and the way it interacts with moisture and temperature. Here's a breakdown of how it works:

• Thermal insulation: Many anti-condensation paints contain hollow ceramic microspheres or other insulating particles. These particles create a thermal barrier on the painted surface, reducing the temperature difference between the wall or ceiling and the warm, moist air in the room. By keeping the surface warmer, the likelihood of the air reaching its dew point is reduced. This insulating property helps to maintain a more consistent surface temperature.

• Increased Surface Area: The textured finish of some anti-condensation paints, often due to the inclusion of porous materials, increases the overall surface area. This allows any moisture that does form to spread out in a thin film rather than forming large droplets, which evaporate more easily into the room.

• Mould Resistance: Many anti-condensation paints also incorporate fungicides or biocides into their formulation. These additives inhibit the growth of mould and mildew on the painted surface, providing an additional layer of protection.

How to apply anti-condensation paint

Proper application is crucial to ensure the effectiveness of anti-condensation paint. It’s important to note that below are general steps on how anti-condensation paint is applied, and it’s vital that you follow the manufacturer’s specific instructions for the product you have.

1. Surface preparation: The surface to be painted must be clean, dry, and free from any dust, grease, mould, or loose paint. Any existing mould should be treated with a suitable mould remover and allowed to dry completely before painting. Fill any cracks or holes and sand down uneven surfaces for a smooth finish.
2. Priming: Depending on the surface and the manufacturer's recommendations, applying a primer can improve adhesion and the overall performance of the anti-condensation paint. Use a primer that is compatible with the anti-condensation paint.
3. Application: Stir the anti-condensation paint thoroughly before use. Apply the paint using a brush, roller, or spray gun, following the manufacturer's instructions regarding the number of coats and drying times.
4. Ventilation during application and drying: Ensure good ventilation in the room during and after application to help the drying process. 
5. Clean tools: Clean brushes and rollers immediately after use with the appropriate cleaner as specified by the paint manufacturer.

Can you paint over anti-condensation paint?

Some products will allow you to paint over without impacting performance, but it’s important that you follow the manufacturer’s instructions and guidance on this, depending on the product you are using.

If overpainting isn't recommended, it's usually because the anti-condensation properties rely on a textured surface that increases the area for controlled condensation, or on specialised chemical additives that manage moisture. Applying a standard paint can flatten this texture, reducing its effectiveness, or cover the additives, preventing them from working as intended. This could reduce the benefits of the anti-condensation paint and lead to mould still appearing.

What is the best anti-condensation paint?

There is a range of great anti-condensation and anti-mould paints available, and choosing the right anti-condensation paint depends on the specific needs of the project, whether it's a large-scale construction development or a targeted solution for a room in a private residence. Here are some that we recommend:

Wykamol Thermaldry

Wykamol is a well-known name in the damp proofing and timber treatment industry, and their Thermaldry anti-condensation paint is a highly regarded product. It's designed to create a thermal barrier that reduces surface temperature differences, minimising condensation. 

Sovereign Fungi-Chek AntiCon Paint

Sovereign is another established manufacturer. Their Fungi-Chek AntiCon Paint is specifically formulated to prevent condensation and inhibit the growth of mould and mildew.

Sovereign Fungi-Chek Emulsion Paint

Similar to their AntiCon Paint, Sovereign's Fungi-Chek Emulsion Paint also offers anti-condensation properties alongside mould resistance. Being an emulsion paint, it provides a decorative finish while actively working to prevent moisture build-up on surfaces.

Waterproofing & damp proofing products for your project

Get your anti-condensation paint from Complete Construction Products. We stock a range of waterproofing and damp proofing products for all kinds of projects. We also offer many other specialist building and construction products, including admixtures, brickwork products, and more. Need further support on how to apply anti-condensation paint or want to find out more information on our products? Contact us today.