The wall rendering process isn’t easy particularly if you don’t know the latest tools, not to mention the techniques and various materials available.
In one of our previous articles, we looked at the different types of rendering finishes. However, irrespective of the various finishes, if you don’t avoid these common wall rendering mistakes, it can likely cost you a lot in the long term via render repairs or starting over again completely.
This article highlights some common rendering mistakes we’ve seen over the years and why you need to be aware and avoid them.
What is wall rendering?
Rendering walls refer to placing a layer of cement or another material such as silicone and monocouche, over brick, stone, or concrete. This is usually done so that the outside layer of cement provides a protective barrier against moisture but also so that the outside layer can be stamped, painted, or stained for a decorative look.
Cement rendering requires expertise and proper understanding of mortar mix that will build the structural integrity of your home.
There are hundreds of different render materials, such as silicone and monocouche, and several recommended manufacturers to choose from, such as K-Rend and Weber.
It’s vitally important you consult professional rendering contractors before getting started to ensure the correct material is chosen.

What Are The Most Common Wall Rendering Mistakes
1. Improper proportion of cement rendering material
In instances where there is excessive use of rendering cement, it may cause several issues during application. Cement renders should be applied with force and placed on walls till it dries up on its own. If the proportions are not correct, the mixture would neither bind with the walls nor fill up the tiny holes or cracks properly. This could eventually lead to broken parts or cracks.
Though these can be handled and corrected by well experienced renderers, you as a homeowner should be careful in choosing the right contractor for wall rendering. We always say to our customers to choose a reputable company who is approved by K-Rend, Weber or other similar approval/accreditation schemes.
2. Lack of preparation on surfaces
Some owners lack time and patience and try to complete the task as early as possible. As such, this is one of the most common wall rendering mistakes in which the wall surface is not prepared properly.
There could be dirt, dust, oil, mud, or any other debris on the walls which can cause the render to not stick properly. Therefore, you need to ensure the wall is cleaned and dried thoroughly before applying the cement render so they bind firmly.
If using a surface that doesn’t absorb very well such as metal or glass, you could consider putting on a dash coat.
3. Overusing the sealer with the rendering materials
Some wall rendering companies believe that using more sealer with a thick paste can help make the rendering work more impressively. However, this is not the case as too much sealer can make the render look sloppy and make the cement seem to glossy and uneven.
Sealers are used only to keep the moisture or prevent staining by giving a clean finish. As a responsible homeowner, you need to check the sealer every year for chips and leaks and avoid adding another coat unnecessarily if it’s in good condition.
4. Lack of force during application
Unlike painting a wall, rendering requires applying some force in order to get the rendering mixture onto the wall and make it stay in place.
More experienced and professional renderers are aware of the type of force necessary to make the rendering stick to the surface with a trowel or a more advanced rendering machine.
You should also add enough layers so that the rendering is thick enough and then scrape off the excess with a flat edge.
How costly are wall rendering mistakes?
Depending on the type of mistakes mentioned above, the impact of each will depend on individual circumstances. However, if these mistakes are not addressed, they are going to be very costly at least in the long term.
Here at Ralph Plastering for example, we always receives hundreds of enquires every year from customers concerned about newly formed cracks in their render. Upon further inspection we always find the initial contractor had either applied the render incorrectly or used an unsuitable finish for the property in question.
This has lead to those customers having to spend more money on repairs and in some cases, stripping off the render and starting again from scratch. Of course, this is something we want to make sure you avoid and why we felt it necessary to write this post.
If you want to consult a professional rendering company in South London and Surrey, then please feel more than welcome to get in touch with our team at Ralph Plastering. We are Weber Approved and hold all the appropriate training and certification which we’ll be more than happy to show in advance to give you peace of mind.
Contact Ralph Plastering today for a free rendering quote and consultation.
View some of our previous rendering projects here.