Basics on rendering external walls with sand and cement

Rendering and repainting external walls is a fantastic way to improve the external look of your property. Depending on the appearance required, the finishing styles can be smooth or rough, natural or decorated, refined or coarse. To get the best 'look', this article gives you a step by step guide on how to apply cement render on external walls.

Step 1: Prepare the wall to be rendered

Before you start, ensure that any paint, dust, plaster or any other friable materials that could hinder the render from adhering are removed with a stiff bristled hand-broom. Thoroughly wet the brick wall with clean water to prevent the cement render from drying out too quickly before adhering.  However, do not render the surface while it is still very damp. Remember to cover the wall with a polythene sheet to protect it from rains and to keep it clean.

Step 2: How to mix the render

Based on the final render finish that you want, pour the render product into a bucket of water according to the mix ratio instructions on the bag. Using a drill, thoroughly mix the two until all lumps are disintegrated into a heavy creamy mix that can easily sit on a trowel. However, if the render is too creamy and wet, discard it and start the process again. If you are mixing the renders by hand, ensure that the same gauge vessels are used for all ingredients.

Step 3: Applying the render to your wall

Set up screed battens of even thickness vertically to the wall to help divide the surface into manageable portions. These battens will also be a good starting point for you to know how thick the render should be applied.

With the help of a steel float, apply the first coat of render and make it as even and smooth as possible. Let the render dry for an hour until it is stiff to touch. Then use a straight edge such as a metal leveler to flatten out the render. Fill any appearing hollows with more render to help close the surface and make it more durable. Lastly, wipe the wall with a clean and damp sponge to give it a nice and smooth finish.

Step 4: Applying Paint on the wall

Leave the wall for a week to let the rendering completely dry before painting it with suitable paint for a desired look.