Concrete may be one of the most durable building materials out there, but it’s still prone to cracking and gradual damage. When concrete structures start to show hairline cracks, it’s worth considering patching them up before they get worse and end up needing more time-consuming (and potentially expensive) repairs down the line. Most of the materials and tools needed for concrete repairs are readily available in hardware stores around the country. Knowing exactly what you need to tackle the problem can be a headache, especially with the market flooded with different epoxy mixes, sealants, resins and mortar mixes. That’s why it’s worth having the information ahead of deciding how best to repair damaged and cracked concrete.

This guide will give you an insight into what concrete repairs involve so you can make an informed decision on how to address the issue.

How do cracks form in concrete?

There are many contributing factors to why concrete starts to crack. The main cause is water. Moisture is the enemy of concrete and it’s a challenge to keep concrete surfaces dry – especially exterior structures. Concrete absorbs water and becomes a destructive force, especially in the winter when it freezes and expands. As hairline cracks form, they give water more of a surface area to enter the structure, exacerbating the issue. The structure as a result weakens in integrity, becoming much more vulnerable to damage through stress and tension.

Repairing cracks

Small cracks in concrete are possible to handle yourself if you feel confident that you and your colleagues are up to the task. Before jumping right into sourcing your materials, it’s worth looking into how much work repairs take. It’s not as easy as injecting an adhesive into the crack and leaving it to cure. Depending on how deep the cracks are, you may have a lot of work cut out for you. Bear in mind that fixing cracks is messy work and you will have to consider the safety of yourself and your crew.

Here’s our process to give you an idea of what’s involved.

Step 1: choose the right materials and tools

A major part of the repair is down to the materials. What we use will depend on the crack type, how deep it is, how exposed the surface is and how extensive the cracks are.

Epoxy or other adhesives
For small, hairline cracks, a pre-mixed adhesive with resin and fine aggregate can fill in fine cracks. Epoxy is the most common concrete adhesive, used to bind the repair in place.

Mortar mix
For larger cracks, an adhesive alone won’t be enough to seal the crack. A mix of adhesive and larger particle aggregate – most commonly Portland sand – can seal cracks.

Step 2: chase out the crack

We use a disc cutter so it’s wide enough to get the material in. A wire brush can pick up the pieces and a paint brush can dust away any niggling excess.

Step 3: fix the cracks

Our process involves a bonding agent which we then apply. The area is then filled with a structural mortar. We then use a finishing trowel to leave a smooth surface behind. We then cover the area to keep it protected as it cures and binds.

Our injection method
Our repair process tackles voids as well as cracks to stabilise the concrete structure and make it water-tight.

This is how we do it.
– We first drill holes at 150 – 200mm intervals or at the leak location.
– We insert injection packers in holes, tighten them and fix one way nipples in each.
– Starting at one end of the joint or crack, we inject Safefoam hydrophilic PU resin through the first packer and monitor progress of resin to the adjacent packer. When the resin has reached the next port, we transfer to the next and proceed in this manner until the flowing leak has ceased or any available void has been filled.
– We leave packers in place for a minimum of one hour to allow resin to cure.
-Lastly, we remove the injection packers.

Why not use concrete in repair work?

The aggregate in concrete contains particles that are too large to fit into small cracks, resulting in a repair that isn’t completely solid. Mixes that are designed specifically for cracks use a much finer aggregate so smaller cracks are filled in properly and sealed.

Let the experts handle it

Going down the DIY route is admirable. That being said, without the industry experience that you need to carry out the job there is a hazard of making errors which could lead to more issues down the line. A lot of concrete damage can be caused by concrete not setting properly in the first place. Without the right knowledge going in, there’s a chance of not filling the cracks properly, not using the right materials or, worse, not taking the right safety precautions. While of course, carrying out the repairs saves your business money, but it could potentially lead to more costly repair works down the line.

That’s why having professional tradesmen and contractors involved gives you peace of mind. You can rest assured that the repair work will be carried out with minimal impact on your business and completed to professional standards in line with building regulations. We also have a 10-year guarantee on our services so you will be covered for maintenance work if there are any problems down the line.

Go straight to the experts

Our team at Concrete Remedials has over thirty years of experience with concrete repairs, from fixing cracks to reinforcing large scale concrete structures. Using high-quality materials that last, we restore concrete surfaces to their full function. We have worked on a number of big projects and builds, including Wembley Stadium, Tate Modern, and Wimbledon Tennis Court.

You can find out more about the types of projects that we handle at our case study page here.

Get in touch with our concrete experts for a quote

Whether you’re after some advice, wish to have a quote, or have questions about our services, feel free to get in touch. You can speak with our experts on 01293 447881 or use our online contact form to send us a message.

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