Painting Render

What Is Render?

Exterior house render is an external wall plaster that is applied on to bricks to create a smooth, attractive finish on the exterior of a property. While providing kerb appeal to a property, render also helps to protect the property from weathering, although the level of protection will vary from render to render.

There are a number of types of render that are widely available in the UK. The most common types of render are:

1. Conventional Render

Conventional render is the standard type of rendering that you find in the UK, providing a budget friendly external solution. Mostly made using sand & cement, they are less advanced than other renders, meaning they can have a lower durability as they are not highly breathable and are rigid, meaning when moisture gets trapped they can crack easily.

2. Acrylic Render

Acrylic render, as the name would suggest, has an acrylic resin added to the mix that provides more water-resistance and flexibility than conventional render, but has low breathability, which leads to damp issues internally.

3. Silicone Render

Silicone render is a render that has added silicone in its mix in order to provide it with a high-quality, water-resistant finish that also remains completely breathable. Without this breathability, moisture can become trapped underneath the render causing it to blow. This is what provides silicone renders with superb durability.

4. Lime Render

Lime render is a traditional form of rendering that has become increasingly popular in recent years. Mostly found on traditional buildings, it offers a natural looking, breathable finish on external walls. Lime render moves and is particularly pervious to moisture, while other renders are rigid. Typically lime render is more attractive than other renders and can help to stabilise the internal humidity of a building by absorbing and releasing moisture.

5. Pebbledash

Pebbledash is a form of render that has added stones & rocks that provide the external wall with a rough surface. Unfortunately, when these small rocks fall out, it can expose the render beneath this which is often not water resistant, leading to water ingress.

Can You Paint Render?

In simple terms, yes, you can paint render. Having said this, there are paints that are more suitable than others. For example, silicone-based masonry paints are better suited for use on silicone renders as the whole point of silicone render is that it is water resistant and highly breathable. By applying a standard masonry paint to silicone render, you remove the benefits of that render.

Similarly using a low breathability masonry paint on lime render will create a barrier on the wall that will seal the moisture within the absorbent lime render, causing major issues. Sealing moisture in any building will cause significant damage, both aesthetically and structurally. When moisture cannot escape from the external wall, it will continue to build up as the moisture enters the render through cracks or soaks through the render if it is not water resistant. This moisture will then cause paint applied to the render to peel, causes penetrating damp through into the internal wall and can even cause damaged brickwork underneath the render.

When painting any render, we recommend you always opt for a highly breathable masonry paint as it will allow the moisture of a building to be freely regulated. We especially recommend only opting for a breathable masonry paint if you have a silicone rendered property or a lime rendered property which is likely to be an older, traditional property that is more susceptible to damp problems. If an acrylic-based masonry paint is used on a silicone or lime rendered property, it would prevent the high breathability of the render.

Why Paint Render?

There are a number of reasons why you may decide to paint render:

1. A Change Of Colour

While some renders come pre-coloured, sometimes a change of colour can be desired. Conventional renders can often come without a coloured finish, meaning they must be painted once dry.

2. Discolouring

Some renders can be particularly prone to discolouration and algae growth, which can be a huge eye-sore on external renders. While the discolouration of the render itself is caused by UV rays, algae and other green growth can grow on exterior renders due to moisture. Many homeowners opt to paint the render once clean to give it a new lease of life.

3. Damage

When moisture causes render to crack, the render can either be patched up using more render or repaired using an exterior filler and then painted over. This is often used as a chance to update the property with a fresh, attractive new colour.

The Best Paint For Render

The longevity of masonry paint & it's weatherproof abilities go hand in hand. Moisture is the single biggest cause of paint failure, which is why silicone masonry paints have been designed. These paints create a water repellent surface on rendered walls that prevents any water being absorbed by the external wall.

While creating this water repellent surface, they maintain full breathability, allowing water vapour to freely escape from the render. This one-way transfer of moisture keeps buildings dry, warm and free from damp. The lifespan of the paint is also significantly higher than standard acrylic masonry paints as the moisture cannot cause paint failure.

The Best Silicone Masonry Paint

When it comes to a silicone-based masonry paint, the most advanced available today in the UK today is Emperor Masonry Paint, which is a completely waterproof masonry paint that creates a super hydrophobic surface on all external renders that prevents 96% of water absorption. It does this while being highly breathable. In an independent test conducted by UKAS accredited laboratory Lucideon, Emperor Masonry Paint was found to have an SD value of 0.60, while the same wall left untreated had an SD value of 0.57. Any surface that has an SD of under 1 is considered breathable, which demonstrated the lack of change in breathability once an external wall was treated using the paint.

In the same 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 when applied to render for decades.

One of the most common reasons Emperor Masonry Paint is used on render is to prevent discolouration. While being resistant to UV rays, which prevents any colour fading, the masonry paint is also self-cleaning, meaning any green growth cannot attach itself to the render. It achieves this thanks to it's water repellent technology, that results in any rain water cleaning the render down, leaving it clean and attractive with almost no maintenance.

Emperor Masonry Paint comes in 12 standard colours but can also be mixed in a range of light and pastel shades.

Pros:

• Super hydrophobic
• Highly breathable
• Self-cleaning
• Proven to keep painted walls up to 6°C warmer on average
• Lifetime guarantee
• Prevents penetrating damp
• Ideal for preventing cracked render

Cons:

• Only available in 12 standard colours
• Is more expensive than other masonry paints on the market

The Best Acrylic Masonry Paint

If you are planning to paint sand & cement render and do not want to spend money on a premium masonry paint, there are other great options. When looking for a standard masonry paint, you want a good-quality paint that offers durability, a great selection of colours and value for money.

When it comes to this, we recommend Armstead Masonry Paint, which is a fantastic all-round masonry paint. While it does not offer the weather protection of a waterproof masonry paint like Emperor Masonry Paint, it still comes in a 15 year lifespan. It offers an excellent trade quality masonry paint, at a great price, plus it can be mixed in any colour you want with the paint mixing machines we have here at Painters World. For the money, you can't ask for much more.

If you do not require a highly breathable masonry paint, Armstead Masonry Paint is a great option.

Pros:

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

Cons:

• Does not offer waterproof weather protection
• Not suitable for breathable renders as it has low breathability
• Is not as high quality as alternatives in terms of finish & opacity

How To Paint Lime Render, Silicone Render & Conventional Render

Looking to paint your render? Here is our expert's step-by-step guide to painting any rendered walls. Ensure you follow each step as they are equally important for achieving long-lasting results.

What 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

Begin by removing any loose paint or material from the surface to ensure it is sound. If the render has been previously painted, check the paint to see if it is intact. If there are any areas that are loose, remove this using a paint scraper.

Any holes or cracks should be filled at this point. Start by removing any render, mortar and rubble from the gap and fill using an exterior filler. Once the filler has dried completely, sand it down using sandpaper to create a smooth surface.

Once the surface is completely sound and free from damage, the next step is to clean it. This is extremely important when painting render as render can be prone to algae growth. If left on the wall, it could grow and eventually cause the paint film to break. Start by removing any large parts of dirt using a stiff brush or a hose pipe. Then, using a brush again, apply a fungicidal masonry cleaner such as Emperor Masonry Cleaner to kill the fungus. Leave the cleaner on the render for two hours minimum. You do not need to clean the render after as any residue will be painted over.

It is then time to put a dust sheet on the floor to prevent paint splatter and mask the edges of the render for the neatest possible finish. A good quality masking tape around doors and other exterior trim is an essential.

2. Priming

With silicone renders and other pre-finished renders, you do not need to apply a primer. On any bare new render, ensure you use an appropriate primer before you paint it. If you don't, the paint could absorb into the render and leave you with a patchy finish. It is important to use the right primer, which depends on the paint you are using. 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. Primers are thin, milky substances that can be applied using a paint brush or a roller. Simply apply a thin but even coating of the primer to the surface and leave to dry completely as per the manufacturers instructions.

If you have any bare areas of render or filler, spot prime these using the primer.

3. Painting

Once the render is sound, clean and primed, it is time to start painting.

It is important to pick a dry weekend where you will have a chance to apply two full coats of paint without the risk of showers, as rain will ruin the project and cause the paint to run down the side of the render. Masonry paints are usually shower resistant in a matter of 1-2 hours.

Starting from the top of the render, use a paint brush to paint around the edges first. You can then use a long-pile roller to apply the first coat of paint to the bulk of the render. Make sure you check the coverage of the paint you are using before applying, which will vary with the roughness of the render.

Allow this to dry completely as per the manufacturers instructions before recoating the paint. A good quality paint will often cover fully in two coats, however apply three coats if you do not achieve the desired finish.

Frequently Asked Questions

Q. How do you paint pebbledash?

The key to painting pebbledash is to use either a masonry brush or a long-pile roller in order to allow you to paint in and amongst all of the gaps that any standard roller would miss. The coverage of the paint will vary hugely with pebbledash due to the amount of surface you have to cover, so make sure you consider this. Except for that, painting pebbledash is no different to painting other render.

Q. How soon can you paint new render?

Render must be dry before you paint it, especially if you not using a highly breathable masonry paint. It is recommended by some to wait up to 4-6 weeks to allow the new render to dry, although the drying time will vary depending on conditions and the thickness of the render. It is recommended to seek this information with the specific render you used before painting to be sure.

Q. What colour should I paint render?

When it comes to painting render, there are a huge range of options depending on the property and the look you want to achieve. White render is by far the most common colour in the UK at the moment, but neutrals like cream and gardenia are increasingly common, while greys like pearl and light grey provide a contemporary look on modern properties. Here are a few of our favourite colours.

White

White is timeless. Whether you have a traditional property or a new build, it brings a new, clean look that works beautifully. While white is famously difficult to keep clean, a self-cleaning masonry paint like Emperor Masonry Paint will keep the render looking pristine without the need to constantly clean it.

An increasingly prominent trend is white rendered garden walls, which we absolutely love. They add striking, clean lines to a garden that are perfect for modernising an outdoor space!

Neutrals

Like lime render, neutral tones such as cream, gardenia and beige can work perfectly on traditional houses. When coupled with other rustic tones such as pale green or wooden shades, they create a uniquely classic, subtle look that does not hit you in the face like brilliant white render.

Grey

Again, providing a more subtle look to white, light greys can be a fantastic choice, especially on a modern looking property. Light grey render is the perfect accompanying shade for the hugely popular anthracite grey that has become the standard for UPVC doors and windows, after white.

We hope this has answered any questions you may have had regarding painting render such as lime render, silicone render and cement render. 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?