What Is Cavity Wall Tie Replacement?
Most brick or stone homes in the UK built over the last 100 years have cavity walls—two layers of brickwork with a small gap (or cavity) in between. This design helps stop damp, reduce heat loss, and cut down on noise.
Wall ties (also called cavity ties or brick ties) are small metal fixings placed in the cavity to connect the inner and outer walls. They help the two walls work together as one strong, stable structure.
Wall ties aren’t just for holding things together—they help manage natural movement in the building, support the weight of the walls, and even maintain performance in the event of a fire. In short, they’re a crucial part of your home’s structural health.
How Wall Ties Have Changed Over Time.
Older wall ties were made from mild steel with a ‘fish tail’ shape at each end. These were usually unprotected, which meant they could rust easily—especially in the outer wall where they’re more exposed to rain and moisture. As they rust, they expand, putting pressure on the surrounding brickwork and causing horizontal cracks to appear.
By the mid-20th century, wall ties were being coated in zinc or bitumen to try and stop this corrosion. These were an improvement, but they were still not perfect. Even a small scratch during installation could lead to rust.
Today, wall ties are made from stainless steel, which is far more resistant to rust and has a much longer lifespan.
When Should Wall Ties Be Replaced?
Wall ties need replacing when they start to fail. This can happen for a number of reasons, such as:
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Corrosion due to age or moisture
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Not enough wall ties used during construction
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Poor installation or incorrect positioning
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Damage to the wall ties during the original build
Whatever the cause, failing wall ties can affect the stability of your home. Replacing them restores strength and prevents further damage, keeping both layers of the wall working properly together.
What Are the Signs of Wall Tie Failure?
Here are some common warning signs that your wall ties may be failing:
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Horizontal cracks running along the mortar joints of your brickwork – often spaced at regular intervals
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Bowing or bulging walls – especially the outer wall
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Uneven surfaces or walls that appear to be pulling away from the structure
As wall ties rust, they expand to several times their original thickness. This forces the bricks apart and leads to cracking. These cracks usually show up towards the top of the wall, where the weight of the bricks is lighter.
If the ties are completely rusted away—especially the thinner wire-type ones—the outer wall can lose support altogether, which may result in visible movement or even collapse over time if not fixed.
How We Check for Wall Tie Corrosion.
As experienced surveyors, we can carry out a full Wall Tie Condition Survey to see if your wall ties are in good shape or if they need replacing.
Here’s what we do:
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Use a wall tie detector to locate the existing ties in your wall.
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In some cases, we use a borescope (a special camera) to inspect inside the cavity—this depends on whether cavity wall insulation is in the way.
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We may remove small sections of mortar to expose the tie ends. This helps us check the type of tie, how deep it’s been set, and whether it’s started to corrode.
Replacing Faulty Wall Ties.
If the survey shows that your wall ties are failing, we can offer advice on how they can be replaced.
Here’s how the process works:
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Find and mark the location of the old ties.
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Install new ties to take over the structural role.
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Remove or isolate the old ones to stop further damage.
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Make good the area so your wall looks neat and clean once the job’s done.
If you're noticing cracks in your walls or just want peace of mind, it’s worth getting your wall ties checked—especially in older properties. Wall tie replacement is a cost-effective way to avoid bigger structural problems later on.