The concept of staining a brick (or other masonry products) has existed for hundreds of years. In 18th century England, diluted cow dung was applied to brickwork to ‘age’ it and encourage the growth of lichen and algae. This method was used frequently, with yoghurt or milk sometimes added to enhance the recipe. Mixing soot with water and applying it to brickwork and masonry was also common practice by builders in England 150 years ago. Unfortunately, the exactness of the colour match left much to be desired and durability was highly questionable with these methods.

In the late 1800s, inspired by the Italian frescoes to the south, King Ludwig of Bavaria ordered his scientists to create a paint that would last through the alpine winters of his country. Previous attempts to beautify their buildings with lime paints failed quickly in their harsh climate. The answer was the discovery of silicates – stains/paints that when properly pigmented and applied to masonry, produced a colour change that would last for years. Since then, continued development has produced formulations that allow for lifespans of 30 years and more. In fact, there are buildings in Europe that were stained with mineral based products over 100 years ago that have never required maintenance.

When choosing a stain/paint for a masonry building, no characteristic is more important than breathability. Every stain/paint product has a perm rating which measures the vapor permeability of the coating – typical acrylic/latex based coatings have a perm rating of 1-7. More advanced acrylic/latex paints that claim to be breathable reach 15-20 on the perm scale. Mineral based paints typically have a perm rating of 75 or higher – significantly higher than other coatings on the market.

The high breathability is due to the microcrystalline structure of mineral based paints – when viewed through a microscope, the coating appears to have millions of tiny holes. These holes are not large enough for a water drop to pass through, but are big enough for a vapor molecule to escape. Thus, mineral stains/paints will prevent water ingress but will never trap moisture on the inside of the wall. These claims have been proven by test results from numerous manufacturers and is often referred to as micro-porosity.

During the summer months, a masonry wall painted with standard acrylic/latex paints will heat up during the day. The heated exterior will attract moisture in the wall causing it to migrate to the surface. Upon hitting the back of the vapor impermeable coating, the moisture will be trapped and will begin to apply pressure on the backside of the coating. As the pressure builds, water sacks or blisters will appear in the coating. Eventually they will burst and this leads to cracking/peeling and failure of the coating. This will never happen with mineral stains/paints as they will not trap the moisture in the wall.

In fact, it is chemically impossible for mineral based stains/paints to peel as they do not form a ‘film’ on the surface.

Durability was the underlying motivation for the invention of mineral based stains/paints in the mid-late 1800s. After viewing the beautiful lime frescoes of Northern Italy, King Ludwig I. of Bavaria began applying similar paints to the buildings of his kingdom. With a much harsher winter season in Bavaria (Northern Alps) the paints quickly failed and he ordered his team of scientists to develop a product that would last in their climate. Mineral stains/paints were invented and their durability is proven by buildings in Europe that were coated in the 1890s and have never required any maintenance (The city hall in Schwyz, Switzerland and Gasthaus Weiber Adler in Stein am Rhein, Switzerland as well as others in Oslo and Germany). Since their invention, mineral based stains/paints have been used widely across Europe and are understood to be the superior coating for exterior building surfaces. This knowledge has not transferred to North America where many builders/architects are unaware of their benefits.

Chemistry is at the heart of the incredible durability possessed by mineral based stains/paints – while standard acrylic/latex paints rely on organic binders which decay over time, mineral paints bond through crystallization of the inorganic mineral potassium silicate. Rather than being a film on the surface that slowly dries out/cracks and peels, mineral paints soak into the surface and petrify within it – they can never peel. Simply put, organic coatings (latex/acrylic) begin to decay as soon as they are applied while mineral based stains/paints never decay.

Of further importance, is the high resistance to UV light – mineral stains/paints do not rely on organic resins (as standard paints do) that dry out over prolonged exposure to UV light causing failure. The potassium silicate binder in mineral stains/paints is exceptionally resistant to UV light and remains stable through decades of exposure. Furthermore, mineral stains/paints are colored only with inorganic mineral pigments which do not fade in UV light – the result is a product that is incredibly durable and will never fade.

Mineral paints are comprised of >95% natural minerals, all of which are highly abundant on Earth. In fact, the main binder (potassium silicate) is derived from the most abundant mineral on Earth which comprises over 90% of the Earth’s crust. This makes mineral based coatings highly sustainable products.

With no chemical additives and an all-natural composition, mineral based stains/paints are completely non-toxic. In fact, leftovers can be left to harden and disposed of in the landfill safely – essentially all that is being thrown out is rock. Because they do not contain chemical solvents, mineral paints are 0 VOC and pose no health risks to those occupying the building.

Mineral paints and stains provide an excellent alternative to replacing old materials thus reducing waste in the landfill and pollution associated with the production of new materials.

Mineral paints and stains are ideal for any absorbent, mineral based surface such as:

• Brick
• Concrete
• Precast
• Stone
• Mortar joints
• Cement renders/stuccos
• Earthen plasters (clay, lime)
• Cement panels (Hardie board, cement board, fibre cement board)
• Magnesium board