What Is Masonry Paint?
Masonry paint refers to exterior paints that are specially designed for use on exterior walled surfaces, including renders, brick or stone. In order to deal the weather conditions that an exterior paint must endure, all masonry paints offer some sort of weather protection. Understanding exactly what is meant by weather protection is crucial to understanding the difference between masonry paints.
There are numerous terms that are used to describe weather protection, including water repellent, waterproof, water resistant & weatherproof. The term 'waterproof' means that water cannot penetrate into a substrate. This term is often overlapping with 'water repellent' which refers to the way in which some masonry paints achieve this waterproof status, by repelling moisture from the surface. After this, there is the terms 'weatherproof' or 'water resistant' which is commonly used in order to describe paints that prevent some level of moisture, but not all.
Types Of Masonry Paint
The type of masonry paint & its level of weather resistance is directly linked. Generally speaking, there are four main types of masonry paint:
ACRYLIC MASONRY PAINT
Acrylic-based masonry paint is the most common type of masonry paint available in the UK. They are water-based formulations that contain an acrylic binder to provide weather protection. The vast majority of acrylic masonry paints fall under the weatherproof or weather resistant category as they prevent some water absorption. After a certain paint, acrylic masonry paints will uptake moisture, which can then become trapped under the paint film as these paints generally have low breathability. This is due to the plastic content in the paint that prevents water vapour from easily passing through the surface.
Eventually, the paint film will be compromised by any moisture that is absorbed by the coating and the paint will peel & flake, allowing even more moisture to get into the substrate. For this reason, acrylic masonry paints come with a lifespan of 3-15 years, with 15 year lifespan estimations from some manufacturers being based on best case scenarios in terms of quality of application and level of weathering.
SILICONE MASONRY PAINT
Silicone masonry paint, or silicate-based masonry paint, is a highly advanced form of masonry paint that contains silicone-resins within its formulation. Silicone masonry paint is water repellent, meaning it will prevent water from absorbing into exterior walls. This, in combination with the high breathability allows it to effectively maintain a dry substrate. As water is the biggest cause of paint degradation, by keeping exterior walls dry silicone masonry paint is extremely durable, often coming with a 20+ year lifespan. Another big benefit of silicone masonry paint is that while it can be used on all substrates, it is highly compatible with silicone renders which is not the case with all masonry paints.
Due to the highly advanced technology in silicone masonry paints, they are slightly more expensive than standard masonry paints. This is because the manufacturing process with silicone masonry paint is extremely difficult. Having said this, the long-term value of not having to re-paint your house every few years is an attractive prospect for many homeowners.
LIMEWASH
Mineral paints such as limewash are a very traditional form of exterior paint that has been used on properties for hundreds of years. While highly breathable & able to give heritage buildings an authentic finish, it does not offer the level of durability of modern masonry paints meaning it is often reapplied every few years. For this reason, silicone masonry paint has replaced limewash as the go-to masonry paint for heritage buildings.
OIL-BASED MASONRY PAINT
Oil-based masonry paint, otherwise known as pliolite, is reserved solely for applying in conditions below 5°C or to prevent the paint from washing off straight after application due to rainfall. Pliolite has a very low breathability due to the oil-based formulation and should not be used unless all other options are not possible, which can sometimes be the case with commercial painting. In a domestic setting, there is no need to use an oil-based masonry paint as you can simply wait till weather conditions permit the use of a higher quality masonry paint.
Is Silicone Masonry Paint Suitable For You?
Breathability is a crucial factor when choosing which masonry paint to use. While some acrylic masonry paints are described as 'breathable', in reality breathability like 'weather resistant' is a term that is used incorrectly.
As we have mentioned, non-breathable masonry paint seals the pores of masonry, trapping moisture & ultimately causing the moisture to build-up within the substrate. If this happens over a period of time, this moisture will lead to significant deterioration in building integrity and cause irreparable damage. The high moisture levels will breakdown the brick, mortar or render, eventually leading to hairline cracks that can allow even more moisture to enter the substrate. When this moisture undergoes a freeze-thaw cycle, it will expand, causing it to open up these cracks even more. Why not read our guide to repairing cracked render for more information?
Aside from external damage, the build-up of moisture will also lead to internal damp problems as any moisture from within a property cannot freely escape. An SD value is a measurement that is used to demonstrate the breathability of a substrate. A substrate with an SD value of 0.5 or below is considered breathable. If a paint does not have an SD value of below 0.5, you should avoid using it.
Emperor Masonry Paint is a silicone masonry paint that has been designed to offer high breathability, as well as water repellent protection that completely waterproofs exterior walls. It uses the latest nano-technology to create a super hydrophobic surface on exteriors that means any rainfall simply falls straight off the painted surface.
It achieves this by lining the pores of substrates while not sealing them completely, allowing water vapour freely pass through them but not water. In independent tests conducted by UKAS accredited laboratory Lucideon, Emperor Masonry Paint was found to have an SD value of 0.03 and prevented water absorption by 96%. It was also tested in a 25-year accelerated weathering process, which found that after 25 years of heavy weathering, it showed no signs of change in appearance or performance. This 25-year performance was under harsh weather conditions where the paint was tested to the extremes of the weather, from freezing temperatures to heavy rain.
Due to this, Emperor Masonry Paint comes with a lifetime guarantee, ensuring its performance in all weather conditions.
Did you know that silicone masonry paint can also keep your home warmer? Damp content of 5% can lower a substrates insulation performance by up to 50%. By keeping exterior walls dry, Emperor Masonry Paint has been shown to keep exterior walls up to 6°C warmer on average.
Frequently Asked Questions
Q. CAN SILICONE MASONRY PAINT BE USED ON K-REND?
As K-rend is a silicone based render, silicone masonry paint is very compatible for use over the top of K-rend. The waterproof & highly breathable properties maintain the performance of the render, while allowing you to choose a colour of your choice.
Q. IS SILICONE MASONRY PAINT APPLIED DIFFERENTLY?
No, silicone masonry paint is just like any other masonry paint. While it isn't completely water-based, it can be cleaned & diluted with water, which means you treat it like any paint.
Q. CAN I REPAINT SILICONE MASONRY PAINT?
Silicone masonry paint is designed for long-term performance. If you apply a standard masonry paint to it, it will repel this paint thanks to the waterproofing properties. You can repaint it using another silicone masonry paint, giving you full flexibility to have a change of colour!
If you are looking a silicone masonry paint to ensure long-term performance, Emperor Masonry Paint is an ideal product to use. Order a sample pot of Emperor Masonry Paint or talk to one of our experts by emailing info@emperorpaint.co.uk or calling 0161 509 9009.