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Renew, Revive: A Comprehensive Guide on How to Fix and Repair Cracked Render on External Walls.

How to Fix Cracked Render

Cracks in externally rendered walls of homes and businesses can be an unsightly sight. Not only do they look unaesthetic, but such cracks can also create safety concerns for your property and weaken its value if not properly repaired. Fortunately, suppose you’re looking to repair a cracked render. In that case, there is a way to revive the walls of your home or business cost-effectively with Renew, Repair, Revive: A Comprehensive Guide on How to Fix Cracked Render and Rejuvenate Your Walls. This guide will give you all the information you need about fixing cracked render step-by-step so that you can restore your wall safely and securely!

How to Fix Cracked Render

What Causes Cracks in External Rendered Walls and How to Fix Them

External-rendered walls are prone to cracking for various reasons, including the natural ageing process of the building, environmental factors, and poor construction techniques. Cracks in externally rendered walls can make your property look unappealing and lead to issues such as water ingress and structural instability. In this guide, we will look at some common causes of cracks in externally rendered walls and how to identify them.

Causes of Cracks in External Rendered Walls

1. Like everything else, the ageing of the Building

Buildings undergo a natural ageing process. Age-related deterioration can lead to cracks in the render, especially in buildings over a few decades old.

2. Environmental Factors

Environmental factors such as temperature changes, moisture, and exposure to extreme weather conditions can cause cracks in the render. For example, if the render is exposed to moisture or water intrusion, it can cause cracks that weaken the structure.

3. Poor Construction Techniques

Construction techniques, such as adequate substrate preparation before rendering, can lead to cracks in the externally rendered walls shortly after the building’s completion. Improper application of the render, including using the wrong mix ratios or tools, can also lead to cracks.

Identifying Cracks in External Rendered Walls

1. Visual Inspection

One of the most straightforward methods for detecting cracks in externally rendered walls involves visually examining the exterior. Be vigilant for any cracks, regardless of size, as they may signify potential issues like structural instability or water damage.

2. Tap Test

Another way to identify cracks is through the tap test. Tap the wall surface with a hammer or a similar tool and listen for any hollow sounds or a change in sound. A hollow sound usually indicates an air pocket in the render, which can lead to damage and cracks.

3. Moisture Test

Assessing the moisture level of the wall can also help identify cracks. Employ a moisture gauge to ascertain the presence of moisture within the render. Elevated moisture levels may result in undesirable outcomes, including but not limited to cracking, as well as the development of mould and decay.

How to Fix And Repair Cracked Render

Repairing a cracked render involves several steps to ensure the repair is effective and long-lasting.

1. Clean and Prepare the Existing Render.

Utilise a power washer or a wire brush to effectively cleanse the current render, eliminating any loose debris, dirt, or algae. After cleaning the wall, allow it to thoroughly dry for a few days before moving on to the subsequent step.

2. Identify and Repair the Cracks

Identify and repair the cracks in the render using a filling knife. Mix the filler according to the manufacturer’s instructions and fill the cracks using an edge tool or a brush. Ensure the filler is allowed to dry before proceeding to the next step.

3. Apply Texture Coats

Apply texture coats to the repaired areas using a trowel or other suitable tool. Ensure that the texture matches the existing render’s texture and colour to create a uniform look.

4. Protect the Wall

Protect the wall from moisture intrusion using a protective coat on the external render. The protective coat enhances the wall’s breathability and protects it from damp or water damage.

render crack repair

The Tools You Need To Repair Cracked Render

Are you tired of staring at the cracks in your externally rendered walls? Repairing a cracked render is essential to restore the aesthetic appeal of your property and ensure its durability and safety. The good news is that with the right tools and a step-by-step guide, you can repair cracked render yourself without breaking the bank. Read on to learn the essential tools you need to repair cracked render and how to use them.

Tools for Repairing Cracked Render

Before you start repairing your cracked render, ensure that you have the following tools:

  1. Filling knife – This is essential for filling the cracks with filler.
  2. Brush – You will need a clean brush to remove all loose debris from the cracks.
  3. Medium sandpaper – This is key to smoothing the repaired area.
  4. Paint – To give your repaired area a colour that matches the existing render.
  5. Render filler – Used to fill in the cracks in the render.

Check out What to do if you spot a crack in your home’s exterior.

Step-by-Step Guide for Repairing Cracked Render on Walls

External rendered walls are commonly used in homes and businesses due to their durability and aesthetic appeal. However, the appearance of cracks on these walls can lead to safety concerns and a reduction in property value if not repaired promptly. This step-by-step guide will explore fixing cracked renderings and rejuvenating your walls.

Identify the Extent of Damage

The first step towards repairing a cracked render is to identify the extent of the damage. Assess the size and location of the cracks to determine the necessary repairs and resources required.

Prepare the Wall

Before repairing the cracks, it is essential to prepare the wall by cleaning it thoroughly. Remove any loose paint and existing render using a filling knife and sandpaper. Ensure the wall is dry and free of any debris.

Fill the Cracks

Once the wall is clean and dry, you can fill the cracks. Use a suitable filler, such as cement or texture paint, and apply it to the crack using a filling knife. Ensure the filler is pushed fully into the crack and levelled to the wall’s surface.

Apply a New Coat of Render

After the filler has been applied and dried, it is time to apply a new render coat. Mix the render according to the manufacturer’s instructions and apply it to the wall edge using a brush or tool. Ensure the render texture is the same as the existing render and the colour matches the exterior wall.

Texture the Surface

Once the new render is applied, texture it to match the original wall surface. Use a medium-grade sandpaper or a texture sponge to create the same texture as the existing render.

Allow to Dry and Reinforce

Allow the render to dry for the recommended time as per the manufacturer’s instructions. Once the surface is dry, gently tap the wall to confirm its solidity. A protective coating will enhance its resilience and shield it from the elements.

How to Fix Cracked Render

Tips and Tricks for Preventing Future Cracks in Render

Rendering plays a crucial role in the outer facade of any structure. It not only provides a shield against external elements but also elevates the aesthetic charm of your premises. However, over time, your externally rendered walls might develop unsightly cracks. While knowing how to fix cracked render is important, preventing future cracks from appearing is equally important. This guide will provide tips and tricks to help keep your rendered walls in top-notch condition.

Choose the right type of render

Choosing the right type of render can make a significant difference in preventing future cracks. For example, selecting a waterproof coating is advisable in regions susceptible to substantial rainfall. Conversely, if you reside in an area characterised by elevated humidity levels, opting for an acrylic coating may prove more effective in warding off cracks.

Ensure proper surface preparation

Before applying any render, ensure the surface is clean, dry, and free from damage. Use a wire brush to remove loose debris and dirt, and fill hairline cracks with a suitable filler. Additionally, ensure the existing render is compatible with the new render you intend to apply.

Apply the render correctly

It’s important to apply the render correctly to minimise the chances of cracking. Use a filling knife to apply the first render coat to the surface evenly and smoothly. After the first coat has dried, apply the second coat using a trowel to achieve the desired texture. Do not apply too much pressure while smoothing the surface, as this could cause significant damage.

Protect your rendered walls

Providing adequate protection to your rendered walls is crucial to prevent future cracks. Use a high-quality paint compatible with the render to add an extra layer of protection against rain and moisture. Additionally, consider installing a cavity wall for proper ventilation and drainage.

Additional Solutions to Rejuvenate Your Walls Beyond Render Repair

While fixing cracked renderings is an effective way to rejuvenate your walls, additional solutions can elevate the appearance and value of your property. This guideline will explore some of these solutions beyond just repairing render cracks.

Repaint Your Walls

Repainting your walls can instantly refresh the look of your property. It is a great option if you are not satisfied with the current colour of your walls or if the existing paint has faded and worn over time. Before you start painting, ensure the wall is clean and free of any loose debris. You can also apply a coat of PVA to ensure the new paint adheres well.

Add Texture to Your Walls

Adding texture to your walls can give your property a unique and stylish look. Several options exist, including using textured paint or applying textured wallpaper. It can be a great way to hide imperfections or damage on your external walls.

Replace Damaged or Outdated Render

Beyond repairing cracked render, consider replacing damaged or outdated render entirely. It can be a more long-term solution that ensures the underlying issues are fully addressed. When choosing a new render, ensure it is compatible with your existing render.

Install Exterior Cladding

While this option may be more costly and time-consuming, installing exterior cladding can provide an extra layer of protection to your external walls and enhance the overall appearance of your property. It is especially useful if your external walls are subject to harsh weather conditions.

Conduct Regular Maintenance

To minimise the need for extensive repairs, it’s important to regularly maintain your external walls, including cleaning and inspecting for any damage or wear. It will allow you to identify any issues early on and prevent them from causing significant damage later.

cracked render

Key Takeaways

  • Remove loose particles, assess damage, and check compatibility between existing and new render. Consider removing significant cracks.
  • Mix and apply using a filling knife and texture tool for a smooth finish. Allow each coat to dry before proceeding.
  • Implement protective measures, such as cavity protection and PVA, for weather resistance. Smooth rough edges for a polished finish after repair.


Can you render over cracked render?

Yes, you can render over cracked render by first repairing the cracks, applying a bonding agent, and then re-rendering the surface for a smooth and durable finish.

How do you seal hairline cracks in render?

Use a flexible, waterproof filler to seal hairline cracks in the render, apply it to the cracks, smooth the surface, and ensure proper curing. It helps prevent water penetration and further cracking.

What paint covers cracks in the render?

Choose a high-quality elastomeric or masonry paint designed to cover and bridge cracks in the render. These flexible paints provide a durable, long-lasting finish while accommodating minor movements.

Can you render over cracks?

Yes, you can render over cracks, but addressing and repairing them is crucial. Use a suitable filler, ensure a stable surface, and apply a bonding agent before re-rendering.

How do you cover cracked renderings?

Covering cracked render involves repairing the cracks with a suitable filler, smoothing the surface, and applying a new render layer. Ensure proper preparation to achieve a seamless and durable finish.

The Bottom Line

Fixing a cracked render doesn’t have to be a difficult task. Instead, you can take control of the situation with Renew, Repair, Revive: A Comprehensive Guide on How to Fix Cracked Render and Rejuvenate Your Walls. This guide gives you the knowledge and practical skills to restore your walls quickly and easily. 

Furthermore, you can save time and money by repairing the cracks cost-effectively, which meets all safety requirements. Taking these steps can also help improve the look of your property and increase its value. 

So don’t wait any longer – pick up Renew, Repair, Revive today, and restore the beauty of your walls!

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About Loftera

Loftera bridges the gap between homeowners and trusted tradesmen, serving as the go-to platform for top-notch home improvement advice and solutions. With a foundation rooted in hands-on construction expertise and a commitment to transparency, Loftera connects you with local, vetted professionals, ensuring quality and reliability for every project. Explore our carefully curated articles, benefit from expert insights, and discover a seamless way to transform your living spaces. Whether you’re contemplating a renovation or seeking the best tradesperson in your vicinity, Loftera stands as your reliable guide in the realm of home improvements.

Joe Bruckland

Joe Bruckland

Construction Expert and founder of Loftera

Having immersed myself in the construction and home improvement world for over two decades, I’ve developed a deep-seated passion and expertise in the intricacies of the industry. My journey, beginning on construction sites and evolving to helm significant home renovation projects, has provided me with a hands-on perspective and a wealth of knowledge that I bring to Loftera. Holding certifications from premier industry bodies, I’ve been a go-to consultant for leading construction magazines, participated in industry forums, and collaborated with renowned tradesmen and architects across the UK. My mission is simple: to demystify the complexities of home improvement, ensuring homeowners are empowered with information that is both current and reliable. Through Loftera, I aim to provide insights that are a blend of field experience and data-driven research, cementing my commitment to be an authoritative voice in the home improvement landscape.

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