0333 5771139
Online Quote

Render Crack Repair: A Complete Guide

render crack repair a complete guide

Cracks in rendered walls can be a real eyesore, not to mention a potential gateway for more serious structural problems. Whether you're dealing with hairline fractures or an ever-growing crack that’s starting to resemble the Grand Canyon, addressing damage promptly will help keep your home in the best possible condition.

Not sure where to start? Read on as we walk you through everything you need to know about render crack repair, including how to assess the damage, prep for repairs and choose the right material for the job.

What are render cracks?

Rendering is a popular building technique used to finish exterior walls. It doesn’t just protect the wall material from the elements, though this is a major role. Renders also improve insulation, repel moisture, enhance kerb appeal and strengthen the underlying structure.

Over time, it's normal for cracks to appear. These can be caused by various factors, such as moisture penetration, settlement, thermal expansion and contraction, or just the natural aging of materials.

Get to know your render

At Total Trades, we work primarily with three high-performance options – silicone render, external wall insulation (EWI) systems and sprayed cork. Here’s a closer look at each:

Silicone render

Silicone render is highly flexible and resistant to cracking, making it an excellent choice for external walls. It boasts a breathable and waterproof finish, along with excellent durability. Silicone render is also self-cleaning, meaning it repels dirt and grime.

External Wall Insulation (EWI) systems

Silicone silicate, mineral and acrylic are some of the most popular materials used for EWI systems. The technique involves fixing insulating material to exterior walls, followed by a layer of render. Benefits include reduced heat loss, lower energy bills and a butter-smooth finish.

Sprayed cork

Innovative and eco-friendly, SprayCork is an extremely popular wall render option. It provides terrific thermal and acoustic insulation while being highly flexible and resistant to cracking. The unique material adheres well to various surfaces, including render, brick and concrete. Plus, it’s available in a variety of colours and finishes to complement the architectural style of your home and your personal preferences.

Common causes of render cracks

Now you know more about external wall render materials, let’s take a closer look at some of the most common causes of cracks:

Settlement: As a building settles, shifts in the foundation can cause cracks to appear in the render. Sometimes cracks are unavoidable and nothing to worry about. Other times they could indicate a more serious structural issue.

Thermal fluctuations: Changes in temperature, for example the transition from winter to spring, can cause building materials to expand and contract. Over time this can damage structural materials and result in the need for render crack repair.

Moisture: Water ingress can weaken external renders and cause them to deteriorate.

Poor application: Incorrect application of render can lead to premature cracking. For example, insufficient curing time or the use of low-quality materials

Assessing the damage

Before getting stuck into render crack repairs, you’ll need to assess the extent of the damage. Depending on your experience and confidence level you can either investigate yourself or call in the experts. Here’s how to approach the DIY route:

Identify the type of crack: Hairline cracks are generally less serious and easier to repair, while larger cracks can indicate more serious issues.

Check for underlying problems: Larger cracks can reveal structural issues that need to be addressed before repairing the render.

Prepping for render repairs

Like painting, preparation is everything when it comes to successful render crack repairs. Here’s what you need to do before filling your cracks:

Clean the area: Remove any loose debris, dirt or flaking render from the cracked area using a wire brush or similar tool.

Wet the surface: Use a clean cloth to dampen the area with water to help the new render adhere properly.

Mix the render: Follow the manufacturer’s instructions to mix the render. Ensure it has a consistent, workable texture before you start applying.

Repairing hairline cracks

For hairline render crack repairs, a simple filler is usually sufficient. Here’s a step-by-step guide:

1. Apply filler

Use a putty knife to apply a good quality filler suitable for exterior use to the crack, pressing it in firmly.

2. Smooth the surface

Smooth out the filler with the putty knife to create a level finish and ensure it blends seamlessly with the surrounding render.

3. Allow to dry

Check the manufacturer’s instructions and let the filler dry completely.

4. Sand and paint

Once dry, sand the area lightly until smooth. If necessary, you may need to repaint the newly rendered area to match the surrounding wall.

Repairing larger cracks

Larger cracks require a more hands-on approach:

1. Open up the crack

Use a chisel to widen the crack just a tad. This may seem counterintuitive, but it helps the new render adhere better.

2. Apply bonding agent

Apply a bonding agent to help the new render stick. This step will improve both the look and longevity of your render crack repair.

3. Fill with render

Apply the mixed render to the crack, pressing it in firmly and smoothing it out with a trowel.

4. Layering

For deep cracks apply the render in layers. Be patient and allow each layer to dry completely before applying the next.

5. Smooth it out

When the final layer is dry, sand it down to achieve a smooth finish and repaint as necessary.

Preventing future cracks

Prevention is always better than cure when it comes to cracked render. Here are some tips to keep cracks at bay:

  • Regular maintenance – Regularly inspect your rendered walls for signs of damage and address issues promptly before they escalate.
  • Control moisture – Ensure proper drainage around your property to prevent water ingress.
  • Quality materials – Use high-quality materials and ensure the render is applied by experienced professionals.
  • Thermal insulation – Efficient insulation can help control thermal movement and reduce cracking.

Smooth the cracks with Total Trades

If you’re looking for cracked render repair, Total Trades can provide a long-lasting solution. SprayCork is often the optimal solution, thanks to the natural flexibility that cork offers. We can use it to seal existing cracks and stop new ones emerging.

If you need assistance with render crack repairs, or any other building or roofing service, don’t hesitate to get in touch with our friendly team. Call us on 0333 5771139 or get a quote online.

Share This Post
Need help with a project?
View More Posts


linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram