If you’ve noticed cracks forming in your external brickwork, you’re not alone and you’re not wrong to be concerned. While some cracks are purely cosmetic, others can be a warning sign of more serious structural issues. Knowing the difference can save you thousands in future repairs.
At CavClear, we’re often called in when cracks start raising questions, and we’re here to give straight answers. Here’s what you need to know about the causes of cracked brickwork, and how our specialist surveys and repairs can help protect your property.
Not All Cracks Are Created Equal
Cracks in brick walls can form for all sorts of reasons. Some develop slowly over time, others appear suddenly after heavy rain or extreme temperature changes. The key is understanding the type, location, and pattern of the crack. That’s what tells us whether you’re dealing with something harmless or something structural.
Here are a few common causes we come across:
1. Wall Tie Failure
Wall ties are small but essential, these metal fixings connect the outer and inner walls of a cavity wall, helping the structure act as one. But when they corrode, snap, or were never installed correctly in the first place, the outer leaf can start to move independently. That movement often shows up as horizontal or stepped cracking, especially on gable ends or long walls.
If your home was built between the 1930s and 1980s, wall tie failure is especially common. It’s one of the first things we check during a survey.
2. Ground Movement or Settlement
Subsidence, heave, or just long-term ground settlement can cause diagonal cracks, usually above windows and doors or along corners. While not always linked to cavity wall issues, these types of cracks are a clear sign that something bigger could be happening beneath your property.
We’ll assess whether wall ties or cavity insulation are contributing to the problem or whether you may need input from a structural engineer.
3. Poor or Incompatible Cavity Wall Insulation
If insulation has been poorly installed or has absorbed moisture, it can lead to damp bridging, which weakens the mortar and causes cracking over time. This can be particularly frustrating, as many homeowners had insulation added to improve energy efficiency—only to find it’s now causing bigger problems.
We use moisture meters and thermal imaging to diagnose whether the insulation is contributing to your cracking.
4. Temperature Changes and Weathering
In some cases, cracks form due to expansion and contraction caused by seasonal changes. These are often minor and may not require urgent repair but they can provide an entry point for water, which eventually leads to deeper issues.
How CavClear Can Help
Our approach is simple: find the cause and fix it properly. We start with a Specialist Wall Tie and Cavity Inspection, using borescope cameras, testing equipment, and expert analysis to identify what’s really going on behind your brickwork.
If we discover failed wall ties, we’ll carry out a full Wall Tie Replacement, using stainless steel ties designed to last the lifetime of your property. We’ll also isolate or remove the old corroded ties to stop future cracking.
If damp or insulation is to blame, we can remove defective cavity wall insulation and provide breathable, modern alternatives, or advise on leaving the cavity clear if that’s the best option for your home. If the damage needs structural reinforcement, we install Helibars, which stitch cracks and restore wall stability without major disruption.
The key is to listen early. Cracks that are left to widen over time often lead to far more costly repairs, and may even compromise the structural integrity of your home. If you’re seeing signs of movement, it’s time to get in touch. Contact us today.
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