How to Repair Cracks in Render

By Jamie Orr
Date 17/08/2020
how to repair cracks in render cracked render repairs

Cracked render is hard to ignore. Not just because it’s an eyesore, but because it can eventually lead to water ingress and damp inside your property. That’s why repairing cracks in external rendered walls is so important.

In this post, we’ll look at some of the options available, how to repair cracks in render with each method, and which is best for your walls.


Technically speaking, render crack repair for the original materials isn’t possible as the render itself can’t be repaired once it’s cracked. Instead, the render needs to be knocked off the wall and replaced with a completely new layer.

Obviously, this option is time consuming and expensive, especially if you’re just concerned about a few cracks. Not to mention that it leads to lots of unnecessary waste with all the existing render going to landfill.

On top of all that, it’s hardly the best option for longevity. After all, what’s stopping the new render from cracking again further down the line? An exception to this would be choosing a new, superior render that won’t succumb to the same issues.

Your render might have cracked because of natural movement in the building materials, for example. In this case, you’ll want a more flexible render which can cope with small, natural movements without cracking.

Alternatively, cracks may emerge due to weathering. In that case, you’ll need to ensure the new render is resistant to water, UV exposure and even salt spray if you live on the coast.

Render crack fillers

One of the most common alternatives for render crack repair are fillers. They come in a range of guises, such as masonry filler, silicone render and repair mortar.

How to repair cracks in render with fillers

There are three steps involved when repairing cracked render with fillers. Firstly, the cracks will need to be cleaned out to create a suitable environment for the filler. Dirt and dust can be removed using a brush or jet wash, but they’ll need to be properly dry before continuing.

Next, cracks can be filled using your choice of filler. If you’re using mortar or cement, you’ll need to carefully apply the filler into the cracks. It’s easier if you’re using a product with a thin nozzle, which can be applied with a caulking gun, so you can quickly and easily fill cracks in render.

Finally, you’ll need to cover the repaired render cracks. It’s unlikely your filler will be a perfect match for your existing render, so you’ll need to paint over to improve the final appearance.

Do they work?

Unfortunately, the reason they’re used so frequently is that these fillers seldom last. By simply filling the cracks, there’s nothing stopping more cracks from emerging on the rest of the rendered wall.

As we’ve covered, this is due to an underlying cause like movement or weathering – and your render’s inability to deal with it.

The other issue is they’re far from invisible. While they might stop moisture ingress in the short term, render repair fillers will leave walls looking even more of an eyesore than the cracks they have filled – even if you paint over them for short-term kerb appeal.

Cork coating

Fortunately, there is an alternative to tearing off the old render or filling in the cracks. Renewing your existing render with an exterior wall coating can provide the appearance and function your walls need.

There’s no need to remove the existing render and start again, meaning less labour and lower costs. That also eliminates the unnecessary waste. By recoating the whole wall, you also get a consistent finish that doesn’t look patched up.

Crucially, it’s a long-lasting, effective option. The coating will stop water ingress and prevent your render from cracking any further. Exterior wall coatings are also naturally flexible, so they can cope with the natural movement of the building. That means new cracks won’t appear.

How to repair cracks in render with SprayCork

Much like the previous option, a SprayCork overspray starts with preparation and filling to tackle the initial cracked render issue you’re facing. To make sure the overspray is a suitable option, an applicator will also check that your render is structurally sound.

The next step takes your render repair from temporary to long-lasting. SprayCork is spray applied in a smooth, uniform coat to cover your entire rendered wall. The coating is naturally flexible, so it can cope with natural movement. It’s also highly resistant to wind, rain, ice and salt spray, so you don’t have to worry about weakening or discolouration due to the weather.

SprayCork comes with a 25-year warranty, so you know it will keep your walls crack-free for years to come. In that time, you’ll also benefit from better insulation to lower your heating bills and reduce the amount of noise that comes into your property. Not to mention your walls looking fresh and new in your choice of colour!

Time to repair your cracked rendering

Looking for a way to repair cracks in rendered walls? As the only supplier who provides a warranty for work over the top of existing renders, CorkSol offers the most effective way to cover cracks in render without leaving visible repair patches.

With an expected lifespan of over 25 years and a choice of colours, our exterior wall coverings combine style and performance to make your cracked render worries a thing of the past. Best of all, we’ve trained a network of applicators across the UK to ensure you get excellent results and all the benefits of our wall coatings, as intended.

Contact our team today to arrange a quote from an approved local specialist.

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