EXTERIOR MASONRY PAINT

Exterior masonry paint is a plastic based paint that contains either silicone or acrylic binder, with the idea to provide a weather and waterproof coating, preventing water from penetrating through to the wall. Masonry paint serves two major purposes – to look good and protect. Exterior paint is very different to conventional interior paints. Due to these being outside, the paint has to perform even better than standard interior paints. Along with adding colour, exterior masonry paint serves to protect a property from weather, pollution and general wear and tear. It is designed especially for use on exterior walls, including brick, stone, concrete, plaster, lime and cement render. Paints are complete with protection against dirt, mould, rain, peeling and UV light providing you with the unique staying power you need. A common cause of failure of masonry paint is the presence of moisture. When the moisture gets behind the paint, it causes peeling of the paintwork, which will need to be rectified. This is why many masonry paints offer waterproofing abilities to prevent this issue and extend the lifespan of the painted masonry. When using a waterproof masonry paint, it is crucial that this masonry paint is highly breathable. This breathability is what allows moisture to escape from inside the property. The breathability of a paint is measured in an SD value. To be considered breathable, a masonry paint should have an SD value of 1 or lower. If a material does not have an SD value of 1 or lower, this will not sufficiently allow water vapour to easily pass through the material. 

One of the best ways to check which colour is best for your project is to try a tester pot. Use these to paint a piece of card, then hold it up to the external wall in different light conditions so you can see what the paint will look like at different times of the day. Try it out in various areas to show the colour in shaded parts of your property, too. One of the great things about today’s masonry paints is that they’re available in a huge variety of colours to suit any style of property. The most popular UK masonry paints colours are Magnolia and White. White masonry paint has to be the most popular choice for homeowners for good reason. It is crisp, clean and can make any home look its best. The worry with white is the fact that it can start to look tired if not cleaned regularly, although with a self-cleaning masonry paint like Ceresit CT49 Nano, this is not a problem as it will remain looking pristine white for years. Thanks to a combination of waterproofing & breathability, CT49 Paint has been proven to withstand harsh weathering for 25 years or longer. However, most people in the UK paint their exterior walls in neutral tones, such as grey or cream.

TYPES OF MASONRY PAINT

There are a number of considerations to make when deciding on what is the best masonry paint for the job. There are also many different finishes of masonry paint that are designed, again, to be more specific to the project needs. There is coarse finish, textured, smooth gloss, matt, satin and heavily textured. Smooth masonry paint will come in different finishes depending on the manufacturer and product, such as matt, satin and gloss. Smooth masonry paint is easier to distribute across large areas and leaves a nice smooth finish – as you’d expect. You’ll find it feels similar to interior walls that you have painted. It is also excellent for covering more problematic surfaces such as pebbledash, roughcast and building blocks. If you’re painting a large surface area, then a ‘Smooth’ version is likely to be your best option as it tends to be more economical for larger areas as good quality textured masonry paints tend to be slightly more expensive per litre. Textured masonry paint offers more protection. If you live in a harsher climate such as a seaside resort or a city with a high level of pollution, texture will serve a better purpose. Its formulation is also ideal for covering fine cracks in existing surfaces so if the surface is slightly "rough", it's probably a better option to go for this type. 

There are 3 main types of finish suitable for masonry surfaces:

ACRYLIC PAINT

Acrylic based masonry paints are perhaps the most common type of masonry paint on the market. It’s ideal if you have a previously painted property that simply needs ‘refreshing’ with a new coat of paint in the short term. These are plastic based paints that contain an acrylic binder. Acrylic masonry paint is cheap, quick to apply and can go over any previously painted surface. However, these ‘modern’ masonry paints have a low level of breathability meaning water vapour can’t easily pass through the painted surface. Invariably over time, water will find its way through hairline cracks in the surface where it can become trapped in the walls, eventually causing the paint to flake and bubble. Acrylic paint can be used for protecting facades, concrete constructions and interiors. It offers great value for money.

SILICATE PAINT

Those mineral based silicate paints form a physical bond with the masonry substrate. A chemical reaction allows the silicate paint to ‘knit’ into the masonry surface, becoming part of the substrate itself. It is highly breathable, durable and weather resistant.

SILICONE PAINT

Silicate paint is naturally alkaline so resists algae growth and is non-yellowing. It has a breathability level similar to that of limewash, making it ideal for older properties, conservation projects and lime render. It is regularly used on listed buildings and heritage properties. A chemical reaction with the mineral substrate means that when used together, the paint and primer form part of the surface, so it is highly durable and weather resistant. It won’t flake off and unlike limewash doesn’t need reapplying every few years.

MASONRY PAINT SIZES | MANUFACTURERS

Several brands can offer matt, smooth or textured exterior paint. A good quality paint should cover 7-8m2 with just 1 liter. Best selling tin sizes are:

• 0.15 ltr offering coverage 0.5m2
• 1 ltr offering coverage 8m2
• 2.5 ltr offering coverage 20m2
• 5 ltr offering coverage 40m2
• 10 ltr offering coverage 78m2
• 12 ltr offering coverage 94m2

A number of masonry paints can be matched to a specific colour, including designer shades or shades of other paint manufacturers. While the colour will not be an exact match, all paint mixing can vary, even with standard colour paints. This is why paint manufacturers always state to get all of the paint you are using mixed at the same time as colours can always vary.

Most popular masonry paint manufacturers in the UK are:

• CERESIT 
• K-REND
• SIKA 
• B&Q
• FARROW&BALL
• DULUX
• SANDEX ULTRA SMOOTH
• WICKES MASONRY SMOOTH
• ZINSSER ALL WEATHER EXTERIOR MASONRY PAINT
• LEYLAND
• RUSTIN
• JOHNSTONE

Those are the most popular smooth and textured masonry paints. They are available in 4,000+ and 1,200+ masonry paint colours – as well as black, grey, anthracite grey, and white masonry paint – with RAL, NCS, British Standard, and own-brand colours and shades.

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Video credit:https://www.youtube.com/watch?v=N1juCG6adcI&t=392s