How to render an exterior wall

Applying render to your exterior walls and finishing off with a roller is a great low-cost way to freshen up the outside of your home. However, please remember that if you're hoping to change the colour of your house, you may have to apply for permission depending on where you live. It's also important to choose the right render and to prepare your surfaces properly before tackling the job.

Steps

1. Clean and treat your walls

2. Fill in exterior wall cracks and imperfections

3. Apply an undercoat or stabilising solution

4. Apply the render

5. Clean up your work space and materials

This preparation stage all depends on the state of your walls. The most important thing to bear in mind is that render must be applied to a clean and dry surface. The surface must be in good condition – never attempt to render a wall that is moist, covered with moss or discoloured by pollution. The tools you'll need for the cleaning and prep stage depend on the condition and size of the surface you want to render.

1. Protect the area immediately surrounding the wall by covering the ground with plastic. Move or cover up anything else you need to protect such as flower beds, air vents and so on.

2. Set up a ladder or a scaffold tower depending on the size and height of the area you want to cover. Ensure the platform is stable before climbing on it.

3. Use a wire brush to tackle any accumulated pollution damage. Move the brush in m² sections working from top to bottom. You can use a basic wire brush or a brush attachment fitted to a drill or angle grinder. The latter option is best for surfaces with stubborn dirt that you don't think a pressure washer alone will be able to handle.

4. Remove the plastic from the ground taking care to clean away the debris.

5. Clean the areas you have brushed down using a pressure washer. Use a special façade cleaner to eliminate any remaining dirt.

6. Rinse the façade thoroughly on a low pressure setting.

7. Apply a hard surface moss killer using a garden sprayer and leave the product to work according to the manufacturer's instructions. You may be able to skip this step depending on the condition of your wall.

8. Next, cover up window and door frames using masking tape, cardboard and newspaper.

9. Cover up the ground once again using the plastic cover.

Shot blasting is recommended for walls with a lot of built-up dirt.

Over time, exterior render tends to crack. If you have noticed any fragile areas or if you have weakened the surface while cleaning, it is imperative to carry out repairs.

1. Repair any surface cracks and imperfections.

2. Use a wire brush or paint scraper to clean out the cracks to help the filler to adhere and last. The exterior filler should be able to fill in cracks as small as 2 mm as well as any triangular hollows where the render has come loose.

3. Remove any dust using a brush, air blow gun or industrial vacuum cleaner.

4. Repair the cracks using an epoxy resin or exterior filler for the largest cracks.

5. Leave the filler to cure according to the manufacturer's instructions.

Depending on the quality and condition of your exterior walls, you may have to apply an undercoat or stabilising solution to prime the surface and create a solid base.

1. Tackle the corners first using an edging brush.

2. Then apply the undercoat with a roller working in criss-cross motions.

3. Leave the filler to cure according to the manufacturer's instructions.

Undercoat can be covered over 12 to 24 hours after application.

There are several different types of render and various application methods. In this guide, we'll show you how to roller over render. Use a ready-mixed mineral render which usually comes in 25 kg tubs. Try to start early in the morning to prevent the walls from heating up too much in the sun. The render must also be stored in a cool place prior to application.

1. Use a stainless steel trowel to apply a thin 2/3mm layer of render spread evenly over the surface. Work in small vertical sections. Use a second trowel as a guide to tackle the edges to ensure your lines stay straight.

2. Use a plastic float to ensure the render is spread in an even layer. Work from top to bottom and then sideways.

3. Coat the roller with render and work it over the surface horizontally starting at the base of the wall. This step is all about starting to build the structure of the pattern.

4. You can then work the surface vertically starting at the bottom and working to the top taking care not to apply too much pressure. The aim is to create an even finish.

5. To finish off, work in horizontal motions again before moving the roller vertically once again from bottom to top.

You might also want to use a special foam roller or stipple effect roller for a more structured finish.

Once you've finished applying the render, you can clean up your equipment and work space.

1. Clean your paint mixer, trowels and roller.

2. Remove the material you used to protect window and door frames and clean up any marks.

3. Remove the plastic from the ground and clean before folding and storing.

4. Dispose of any waste at a recycling centre.

Required skills

No particular skills are required beyond being able to work on a ladder and follow the manufacturer's instructions.

Time required

Depends on size and condition of surface

Number of people required

One person

Tools and equipment

• Ladders or scaffold tower

• Pressure washer

• Masonry detergent

• Wire brush

• Undercoat

• Ready-mixed mineral render

• Stainless steel trowel

• Plastic trowel

• Paint mixer

• Long pile masonry roller

• Exterior render

• Exterior filler

• Trowel

• Sealant gun

• Protective sheets

• Masking tape

Safety and workwear

• Protective gloves

• Safety goggles

• Protective clothing

• Safety shoes

Please note: this is a non-exhaustive list; be sure to match your personal protective equipment to the job at hand.