An Experts Guide To Painting Masonry

What Paint Do You Use On Masonry?

Knowing what paint is suitable for your project is the first step in ensuring you achieve the best possible results. If you do not use the correct paint, it will not adhere properly to the surface and will leave you needing to repaint the surface once again when the paint fails.

Masonry paint is a paint that is designed to be applied to exterior walled surfaces, such as render, brick, stone & concrete. As exterior walls must endure high levels of weathering, masonry paints come with some level of weather protection, although the level can vary from paint to paint.

The level of protection generally depends on the quality of the paint and the type of masonry paint it is. The two key things to consider when buying a masonry paint are

1. Its ability to keep rain out
2. Its ability to breathe

If a paint allows water to get underneath the paint film, then it can cause the paint to peel & flake. Similarly If a paint has little to no breathability, any moisture that is present within the wall, either from condensation or from rain soaking in, will get trapped. This will then cause a build up of pressure that will cause the paint to fail.

There are four broad types of masonry paint on the market today:

Acrylic Masonry Paint

Acrylic masonry paints are the most common type of masonry paint available in the UK. Acrylic masonry paints are water-based formulations that are weatherproof, meaning they will resist some weathering, however they are not waterproof and will uptake some level of moisture over time. These formulations are also generally low in breathability when compared to other formulations and come with lifespans anywhere from 1 year to 15 year, depending on the manufacturer.

They are generally cheaper than other formulations and are available from all of the leading paint manufacturers such as Dulux, Crown & Sandtex.

Silicone Masonry Paint

Silicone masonry paint is a technologically advanced masonry paint that contains silicone-resins within its formulation. These paints have a modified formulation that mean they are treated like a water-based paint.

The silicone gives the masonry paint water repellent properties meaning it will prevent water from absorbing into exterior masonry. They achieve this while also offer high breathability, allowing any trapped moisture to freely escape the masonry. This is what gives silicone masonry paint a highly durable finish that is ideal if you want to protect your masonry from weathering. Silicone masonry paints generally come with lifespans in excess of 25 years. It also has self-cleaning properties as any dirt is simply washed off the exterior masonry by rainfall.

Silicone masonry paint can be applied to any exterior masonry or render. If you are painting a silicone render such as K-Rend, you must use a silicone masonry paint as other masonry paints are not compatible with these renders.

The downside to silicone masonry paint is that due to the advanced technology in the paint, it is often only available in light or pastel shades. This means that if you are looking for a deep or dark shade of paint to give you home a unique look, you will struggle to find the right colour for you.

Limewash

Limewash is a traditional form of masonry coating that is highly breathable, which is why it has been used on heritage buildings for centuries. Limewash as a natural form of masonry coating does not offer the some weather protection as modern masonry paints, which is why it has to be recoated every few years. Due to this, many heritage properties are painted with silicone masonry paint to maintain the high breathability that is required in order to protect older properties.

Oil-Based Masonry Paint

Oil-based masonry paint, otherwise known as pliolite, is solely used when temperatures are below 5 degrees. Due to its low breathability it is not recommended for use unless in specific commercial projects where a water-based paint can't be applied.

Which Paint Is Right For Me?

Ultimately, when painting masonry, the paint that is right for you will depend on what you want to achieve. If you want the maximum amount of durability, or you want to keep your exterior masonry clean without regularly maintenance, a silicone masonry paint is you best shot. Alternatively, you may be looking to paint a garden wall, in which case an acrylic masonry paint will be the easiest and cheapest option to complete the project.

The Best Paints For Masonry

When deciding what masonry paint is best for you, it is important to consider what you want from your paint. Do you want a cheaper paint that will allow you to change colours regularly or do you want a paint that offer more waterproof protection to your home?

Here are our experts picks for the best paints for exterior walls:

1. Emperor Masonry Paint

When it comes to a highly advanced silicone masonry paint, look no further than Emperor Masonry Paint. Emperor Masonry Paint creates a super hydrophobic surface on exterior walls that prevents 96% of water absorption. It achieves this by creating a water repellent surface on masonry that means any water that lands on the painted surface simply beads off.

It does this while being highly breathable, allowing any moisture within a substrate to naturally breathe out. This combination of water repellence & breathability gives Emperor Masonry Paint an unmatched durability. In independent testing, Emperor Masonry Paint was found to have no change in appearance of performance after a 25-year accelerated weathering period. Due to this, Emperor Paint offer a lifetime guarantee on their masonry paint, ensuring it's performance for decades.

One of the most popular benefits of Emperor's silicone technology is the self-cleaning properties. Many homeowners will be familiar with large green patches on exterior walls, especially when they are painted white. Preventing water absorption means that exterior masonry stays looking clean and free from moss, lichens & other organic growth.

Emperor Masonry Paint can also help insulate exterior masonry. This is because wet walls transfer heat much quicker than dry ones. By keeping exterior masonry dry, Emperor Masonry Paint has been shown to keep walls up to 6°C warmer on average.

Emperor Masonry Paint comes in 12 standard colours, which is less than other masonry paint manufacturers. This includes white, off-white, witney cream, beige & light grey, plus a number of pastel pinks, blues & greens. While it is more expensive than other masonry paints on the market, Emperor Masonry Paint is designed to offer better long-term value, as it prevents the need to repaint the masonry every few years when other paints can fail.

Want to see the colours in person? You can order a tester pot of Emperor Masonry Paint to find the right masonry paint colour for you.

Pros:

• Super hydrophobic
• Highly breathable
• Self-cleaning
• Proven to keep painted walls up to 6°C warmer on average
• Lifetime guarantee
• Prevents penetrating damp
• High opacity

Cons:

• Only available in light or pastel shades
• Is more expensive than other masonry paints on the market

2. Armstead Masonry Paint

When it comes to a standard acrylic masonry paint we recommend Armstead Masonry Paint. This is the ideal paint if you are looking for a trade-quality masonry paint that offers great value for money & a high quality finish. While it does not offer the weather protection of a silicone masonry paint like Emperor Masonry Paint, it still comes in a 15 year lifespan which is higher than many retail masonry paints that you will find on the shelves at DIY stores.

Armstead Masonry Paint is especially useful if you are looking for a specific colour, as it can be mixed in almost any colour you want. Whether you want a specific RAL or British Standard colour or you want it colour matched to an equivalent of another brands colour, it can be done with Armstead Masonry Paint.

Pros:

• Shower resistant
• 15 year lifespan
• Can be mixed in almost any colour
• Cheaper than other trade masonry paints

Cons:

• Does not offer waterproof weather protection

3. Dulux Trade Weathershield Maximum Exposure

Dulux Trade Weathershield Maximum Exposure Smooth Masonry is a high-quality trade masonry paint that offers 5x more flexibility than conventional masonry paints. This makes it ideal for covering hairline cracks on masonry, leaving you with a smooth, uniform finish. Like Armstead Masonry Paint has a 15 year lifespan, plus it offers protection from mould & algae as it contains a fungicide within its formulation.

It can also be mixed in almost any colour, including RAL, British Standard, NCS & equivalents of all major paint brands.

All in all, if you are looking for a high-quality acrylic masonry paint, this is a great option.

Pros:

• 15 year protection
• 5x more flexible than conventional masonry paints
• High opacity
• 14m² per litre coverage

Cons:

• Does not offer waterproof weather protection
• Is more expensive than other options

How To Paint Exterior Walls

When painting masonry, you will need:

• Masonry paint
• Long-pile paint roller
• Paint tray or scuttle
• Paint brush
• Sandpaper
• Dust sheets
• Masking tape
• Exterior filler & filling knife (may be required)
• Scraper (may be required)

1. Preparation

It is tempting to rush the preparation stage, however what many people do not realise is that the preparation stage is the most crucial part of any decorating project like painting exterior masonry. If you do not prepare the surface properly to be painted, you will run the risk of not only achieving a scruffy finish but also the paint failing.

The first part is to remove anything from the masonry that can compromise the finish or the ability for the paint to adhere to the wall. Start by removing any loose or defective paint from the wall to ensure it is sound. Using a scraper remove the paint until you have a firm edge where no paint will continue to come off the wall. Any holes or cracks can be filled using an exterior filler & a filling knife. It is important to remove any loose material from inside the crack or hole before filling in order for the filler to dry solid.

Once the surface is sound, it is time to clean it. Much in the same way of removing loose paint, this ensures there is nothing on the wall that will prevent to paint from adhering. Remove any large bits of dirt using stiff brush or a hose pipe. You can then apply a fungicidal masonry cleaner such as Emperor Masonry Cleaner to the wall, which will kill any fungal growth that is on the masonry. If you do not do this, any fungal growth will be left underneath the paint film and could later cause the paint to peel. Apply the cleaner undiluted to the masonry with a brush and leave the cleaner on the exterior wall for a minimum of two hours. You do not need to remove the cleaning solution from the wall before painting.

You can now cover any surfaces that you do not want to paint by putting down a dust sheet on the floor & applying masking tape around windows, doors & other exterior trim. A good-quality masking tape is the secret to achieving a beautifully neat finish. We recommend you use an exterior masking tape such as Q1 Precision Line Masking Tape. You can also apply a film in order to protect windows, such as Q1 Pre Taped Washi Film 550mm x 33M.

2. Priming

If you are painting a bare masonry surface that has not previously been painted you should apply a primer before painting. By applying a primer, you prevent the paint from absorbing into the wall, which results in a patchy finish. Primers can also help provide added adhesion, allowing the paint to perform more effectively long-term.

With Emperor Masonry Paint, Emperor Paint® Exterior Masonry Primer must be used as it contains the same water repellent technology. With a standard masonry paint, you could you a universal primer such as Zinsser Bullseye 1-2-3. It is always important to check with the manufacturer which primer should be used with their paint if you want to ensure the best possible results.

Apply a thin but even coating of the primer to the masonry using a brush or roller and leave to dry completely as per the manufacturers instructions. Primers are not as thick as paints so be careful not to splash on any other surfaces as this can be difficult to clean off once dry.

If the surface you are painting has been previously painted, you do not need to apply a primer. Simply spot prime any areas you have removed paint to ensure these sections are adequately prepared.

3. Painting

When the exterior masonry is dry, sound & primed if required, it is time to paint. A long-pile roller is the best way to apply paint to exterior masonry as it has long fibres that allow you to apply large amounts of paint to textured surfaces. A paint brush is required also in order to paint around the edges of the wall. You can spray masonry paint using a spray machine, however this is specialist equipment that you should only use if you are a trained professional.

Apply the first coat of paint, starting with the paint brush around the edges of the wall and finishing with your paint roller on the rest of the masonry. If you are painting a rough textured exterior wall such as pebbledash, the coverage of the paint you are using will be reduced so you should check the manufacturers instructions for further advice on the coverage you want to achieve with the paint. Not applying enough paint will leave you with a patchy finish and too much paint can cause the paint to drip and result in a poor finish.

Allow your first coat of masonry paint to completely dry before applying a second coat. While most water-based masonry paints will be touch dry in 1-2 hours, the recoat time of the paint will be longer than this. A good quality masonry paint will often cover fully in two coats, however apply three coats if you do not achieve the desired finish.

You can then remove the masking tape and clean you tools with water, if you have used a water-based paint.

Frequently Asked Questions

Q. What finish does masonry paint leave?

You will find that most masonry paints will leave a matt finish, which has the lowest level of sheen of paint finishes. You can get masonry paints in an eggshell finish, that has slightly more sheen than a matt finish, if this is what you desire.

Q. Why is my masonry paint flaking?

If you are looking to paint over areas of exterior masonry that has had paint previously fail, it is important to understand why in order to ensure it does not happen again. There are a number of reasons why masonry paint can fail.

• Water ingress - when water gets behind a paint film through water ingress, it can cause the paint to peel & blister. The water can enter the masonry in a number of ways, either by absorbing into the masonry paint if it is not waterproof or by entering through hairline cracks.
• Poor adhesion - not using a primer or using the wrong primer could lead to poor adhesion, which in turn can cause paint to blister. This is why applying a primer to bare surfaces is crucial if you want the best possible results.
• Poor preparation - not properly preparing the surface by cleaning it thoroughly can lead to paint failure. This is why it is important not to rush the preparation stage of the project for the sake of saving an hour.
• Compatibility - if you have used a paint the is not compatible with the surface you are painting it will cause the paint to fail. This for example can happen if you paint a silicone render with an acrylic masonry paint. You must ensure you use a silicone masonry paint if painting silicone render.

Q. How much masonry paint do I need?

The amount of paint you will need depends on the paint you are using, the size of the area and the number of coats required.

Every paint manufacturer gives an estimated coverage of their paint on smooth & rough surfaces. Emperor Masonry Paint for example has a coverage of 5-6m2 per litre on smooth surfaces and 2-3m2 on rough surfaces.

In terms of the size of the exterior wall, this should be estimated on metres squared. Simply measure the length of the wall & the height of the wall, then multiply these together. This will give you a total metres squared figure.

Finally, a good quality masonry paint will cover in two coats, while cheaper options will require three. This is something to check before you decide on which paint to use as you do not want to cost yourself time having to order more paint if you run out before painting the full area of exterior masonry.

Q. When painting masonry, what tools should I use?

Ultimately, the decorating tools you use when painting masonry are up to you, however there are a few things that will help. Firstly, use a long-pile roller when painting rough surfaces like masonry as not only does it help cover large areas quickly, but it also means due to its long fibres, that you can get the paint in all of the small gaps and bumps that you find on textured surfaces. Aside from that, we recommend using good-quality supplies where possible, as this will help you achieve the best possible finish, as easily as possible.

Q. When painting masonry, what tools should I use?

We hope this has answered any questions you may have had regarding painting masonry. If you require any more help, just send an email to hello@paintersworld.co.uk and our expert team will be on hand to give you any advice you require. At Painters World we have a wide range of paints available, so no matter the job, we've got the right tools for you. We offer FREE next working day delivery on all orders over £50, so what are you waiting for? Shop our full masonry paint range.