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Q&A - What Should I Know About Breathable Paints?

Paul Mcgovern

By Paul Mcgovern

Monday 15th August 2022

When it comes to paint, the term 'breathable' means that moisture vapour can pass through to the surface with minimal restriction. Many conventional synthetic paints contain plastics such as acrylic, vinyl and latex which can limit the passage of moisture vapour or emit potentially harmful gases. Below, we take a look at some common questions regarding genuinely natural breathable paint.

Q&A - What Should I Know About Breathable Paints? Q&A - What Should I Know About Breathable Paints?

What does 'breathable' mean?

A truly breathable paint will allow water vapour to pass through and evaporate from the surface. It won't slow down or stop this transfer from occurring. Numerous paints on the market claim that they are breathable, but how can one tell that they freely allow moisture to pass through? Thankfully, there are lots of ways to measure how breathable a material is. When it comes to paint, the most common way of measuring this is by referring to a unit of measure called the Sd value.

What is an Sd value? 

The Sd value is a measure of how much resistance to moisture diffusion a material has, when compared to a meter of air. The higher the Sd value, the greater resistance to vapour diffusion. Lower Sd values are more vapour open and are therefore more breathable. Breathable paints should have Sd values ranging from 0.01 to 0.1 which are typically found on the product technical data sheet. If the Sd value is not shown, you need to ask, why not?

Natural minerals and pigments in Auro paint
Only natural minerals and pigments are used in Auro paint
Blue colour Auro natural paint being rolled onto a wall.
Auro natural paint can be easily applied by brush, roller and sprayer.

What are the benefits of breathable paint?

Breathable paints benefit old buildings as well as new. In older buildings the solid walls may contain moisture which needs to pass through the fabric to escape. Covering these with a non-breathable paint, such as those that contain vinyl and acrylic, will potentially seal that moisture in and lead to problems with dampness and mould. It can even lead to the paint blistering, bubbling and in severe cases peeling off the surface. Can you imagine applying a layer of cling film to your walls or ceilings? This gives you an idea of what it’s like to apply a plastic paint and shows how moisture can become trapped and accumulate within the building fabric. This can be detrimental to the building and harmful to the occupant’s health.

Furthermore, some conventional paints contain plastics derived from petrochemicals. This has a negative impact on our health and the environment. The use of crude oil to produce these materials can lead to the creation of harmful toxic waste. Modern paints mostly use Azo dyes as their colourants which are made using chemical compounds. Auro natural breathable paints are made using only natural minerals and pigments.

Can I use a breathable paint on non-breathable materials?

Even if your plaster is not breathable, finishing it with a breathable paint has its advantages over using petrochemical paints. Firstly, we spend a lot of time indoors these days and the coatings we use have an effect on the air quality and our health. By using a breathable, natural paint you will improve the indoor air quality of your building.

Breathable paints also have the ability to regulate humidity by absorbing excess moisture and releasing it in drier conditions (paint can be a natural dehumidifier). Auro Clay Paint 535 is particularly good for this and is very suitable for bathrooms or in any area which has a lot of moisture.

How do I apply breathable paints?

Breathable paints are applied in the exact same way as conventional paints. The Auro collection of breathable paints can be easily applied by brush, roller or spraying. There are over 800 colours to choose from which are pre-mixed in our tinting machine. Auro natural paint is durable and wipeable and can be cleaned with a damp cloth.

A stool being painted blue using Auro natural paint
Auro natural paint does not emit any VOCs and is safe to use on all indoors surfaces

What impact does paint have on our environment?

Celtic tree mural in Derryounce woods painted with Auro natural paint
Tree murals in Derryounce woods painted using Auro natural paint. Auro was chosen for this project due to its natural ingredients and pigments.

Regrettably, synthetic paints can have numerous negative impacts on the environment over its lifecycle. According to researchers, a staggering 58% of all the microplastics in our oceans and waterways come from paint, which equates to 1.9 million tonnes of paint per year. This outweighs all other sources of microplastics, including textile fibres and tyre dust. Even “water based” paints can contain a significant amount of plastic.

Using a natural paint such as Auro can help offset this environmental impact as well as optimise overall breathability. Auro contains no plastics and is so pure that it was chosen for a series of tree murals in Derryounce woods.

Thinking of using a breathable, natural, eco-friendly paint? Check out our collection of premium colours here.

Blog author

Paul Mcgovern

Paul Mcgovern

Technical Sales

Paul is responsible for the Auro natural paints department and has over a decade of expertise  in the industry. Paul graduated from Athlone I.T with a BA in Management and previously worked in the paint sector for over 7 years in both Sales and Management, he has brought a great wealth of knowledge and experience with him when he arrived at Ecological in 2017. As the paint sector is rapidly evolving, Paul is at the forefront with regard to training, insights and awareness of sustainable products.

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