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Masonry Paint Information and Comparison
The Importance of Breathable Masonry Paints
Breathable paints allow moisture vapour to escape from within the masonry, whilst being weather proof. This works in much the same way that you get waterproof breathable clothing and tents.
If the paint is not breathable then moisture in the wall will cause damage as it expands and contracts in freezing weather. Excessive moisture in the wall will cause the masonry to deteriorate (this usually happens through salts crystallising putting pressure within the masonry).
Having a low-breathability or non-breathable masonry paint can cause damp problems within the house as well as within the masonry, causing excessive moisture inside and eventually mould growth.
Film forming paints
These are your conventional masonry paints, they contain acrylics and organic polymers, usually of petrochemical origin.
Unlike silicate paints which soak into the surface of the masonry, film forming paints form a skin with a very low breathability over the masonry.
If the film cracks or peels the system will soon fail as moisture gets into the masonry and is unable to escape
Although the breathability can be increased by using inorganic fillers, film forming paints also have other disadvantages:
- Stressed by building movement
Buildings expand and move slightly throughout the year with the changing temperatures and environmental conditions. If the film is not flexible enough to allow for this movement, the film will crack under stress and the system will fail.
- Degraded by the sun’s rays
Exposure to the sun causes the paint’s colour to fade over time, and causes the film to become increasingly brittle. After months of exposure to the sun’s rays the brittle film can crack and cause the system to fail.
- Damaging to health and the environment
Conventional masonry paints contain volatile organic compounds (VOCs) which are widely accepted as being damaging to both the environment and human health.
Limewash
Limewash provides a breathable and decorative finish on traditional properties.
Many coats of limewash are usually applied, and are slowly washed off by the weather – it is a ‘sacrificial coating’ protecting the masonry while it lasts.
Although limewash requires more maintenance than other masonry paints, many traditional buildings use limewash to retain their original looks.
There are many reasons to use limewash, and many factors to consider, which we will cover in another article.
Silicate Paints ( also called silicate masonry paint or silicate mineral paint.)
These are hi-technology paint systems which have the breathability of limewash, while being highly durable
– more so than conventional masonry paints.
Silicate paints soak into the masonry; the binder forms a strong silicate mineral bond between the paint and masonry. This gives a highly durable, and breathable yet weather resistant finish.
- Weather resistant
The paint’s structure is open enough to allow water vapour to pass through, but small enough to stop driving rain from entering the masonry. - Beautiful UV Stable Colours
The natural earth pigments in silicate paint are not affected by UV rays. The paint retains its colour throughout its life. - Protection that lasts for decades
A popular masonry system in Europe, silicate mineral paints have been documented to last for over 100 years on lime based renders in Germany, Switzerland and Norway.
We at Celtic Sustainables believe that silicate paints are the best value paint system on the market.
That’s why we recommend the Earthborn Silicate Masonry paint - a high performance and environmentally friendly silicate paint, available in 48 vibrant colours.
See the colour range and buy from our online shop.
There’s more information on the Earthborn Silicate Masonry Paint and Primer, including the colours and datasheets on our Earthborn Silicate Masonry Paint product page.