Silicate paints are superior for sealing and decorating your masonry home
Do you know what type of paint is best for use on inorganic materials such as concrete, brick and stone? It’s not oil, latex or acrylic…This paint has a liquid potassium silicate base, which is an inorganic compound composed of potassium, silicon and oxygen. A.W. Keim invented and patented “silicate” paint in 1878 in Germany in response to King Ludwig I of Bavaria’s desire to have frescoes that withstood the harsh weather of his kingdom. Buildings decorated with KEIM silicate paints in the 19th century are still in excellent condition today. (The history of a groundbreaking idea)
Keim did not invent potassium silicate; also, known as “waterglass”, it was made in small batches since the middle ages but lacked a reliable production process. This is where Keim made his mark; he started developing paints that lasted by chemically bonding with the surface. The potassium silicate “petrifies” in a process called silification, locks the paint into the substrate. Interestingly, potassium silicate is also used as a concrete densifier, plant fertilizer, corrosion inhibitor, and as a fire retardant in wooden homes. (What Is Potassium Silicate Used For)
Another durable feature of silicate paints is that they have high water vapour permeability due to their crystalline nature, which ensures that humidity present in the masonry can freely pass from the substrate. As we’ve explained in previous articles, brick and concrete are porous, meaning that water will pass through them freely. If you place a vapor “barrier” (non-permeable) coating on them, then the masonry can only dry out in the other direction, and the coating will tend to bubble and peel off due to trapped moisture. (THE BASIS OF MINERAL SILICATE PAINTS) This property also reduces the growth of mold on the surface, because condensation and trapped moisture are not issues and the paint itself will not support microbial growth (unlike latex and other types of paint).
Since silicate paints were developed with art in mind, they can actually be made in a range of colors. Other powdered minerals are used to “tint” the base into many colors. Factory-tinting used to be the standard, but now companies such as Silacote have discovered new ways to tint paint on demand at retail locations, similar to other types of paint. The colors stay true for decades even in outdoor (UV) light and acid rain, because the minerals themselves do not fade, in contrast to other types of paint that require special UV coatings to prevent fading. (What is Silacote?)
Other positive features of silicate paint is that it sheds water. Silacote Primer/Sealer with its potassium silicate base has the powerful effect of consolidating and filling microscopic pores and channels by crystalline formation. This results in liquid water rejection from the surface while still allowing the wall material to transmit water vapor (breathe) as necessary to equalize to it’s environment. (CORRECTING WATER ABSORBTION ON POROUS SURFACES) It also does not burn or produce hazardous gases when exposed to flame, and the lighter colors actually help the building to reflect or shed heat from the sun.
If you’re falling in love with all of these features but are not ready to repaint the exterior of your home, silicate paints are suitable for interiors, too, and are safer than traditional paints because silicate paints have zero VOCs. They have a matte finish similar to limewash paints which makes rooms very calming and inviting. Inside, they may be applied directly to masonry walls like brick, stucco, cement and plaster; it works on magnesium oxide (a type of wallboard) well too. If applying to paper-coated drywall, a mineral-based primer must be applied first. The paint dries quickly and should not be allowed to form dry edges while painting, otherwise blotchiness may be apparent in the dried finish. For this reason, sprayers are a good way to apply most silicate paints, so that a “wet edge” is maintained throughout the surface until it’s fully coated.
For a very natural kind of paint that bonds to your walls for a timeless look, we suggest trying silicate paints on your masonry walls, whether in the garden or home.
Photo from House Beautiful
