Cavity wall ties play a crucial role in maintaining the structural integrity of a building. Designed to hold together the inner and outer leaves of a cavity wall, they prevent movement and ensure the stability of the property.
However, in older homes, these ties are often prone to rusting and wall tie corrosion, leading to significant structural issues if left unchecked. But why is this such a common problem in older properties? The answer lies in the materials and construction methods used in the past.
What causes Cavity Wall Ties Corrosion?
Cavity wall ties are typically made of metal, which, when exposed to moisture and oxygen over time, can corrode. This is particularly common when the protective coatings on the metal begin to degrade. Once corrosion sets in, the ties weaken, and in severe cases, they can fail completely, causing instability in the wall structure.
The key reasons for wall tie corrosion include:
- Moisture ingress – Water penetration into the cavity accelerates rusting.
- Poor quality coatings – Early forms of galvanisation or protective coatings were often inadequate.
- Condensation within the cavity – Inadequate ventilation can cause moisture buildup, further contributing to corrosion.
- Chemical reactions – Certain older mortar mixes contain materials that exacerbate rusting.
Why Are Older Homes More Affected?
Older properties, particularly those built before the 1980s, are significantly more vulnerable to wall tie corrosion due to the types of materials and installation techniques used at the time.
1. Mild Steel Wall Ties
Many homes built before the 1980s used mild steel wall ties, which were either ungalvanised or had insufficient protection against rust.
Over time, exposure to damp conditions caused these ties to corrode, leading to expansion within the mortar joints and, eventually, structural damage.
2. Cavity Insulation Issues
Older homes were often retrofitted with cavity wall insulation, which can trap moisture within the cavity if not properly installed.
This additional moisture creates the perfect environment for wall ties to corrode at an accelerated rate.
3. Changes in Building Regulations
Modern construction standards require the use of stainless steel or heavily galvanised ties, which are far more resistant to corrosion.
Many older homes were built before these regulations were in place, leaving them vulnerable to premature tie failure.
When cavity wall ties corrode, they expand as rust develops, which can cause several serious structural problems, you can read more about this here.
How to Identify and Address Wall Tie Failure
If you live in an older home and are concerned about cavity wall tie corrosion, it’s important to look out for the warning signs.
If you’ve spotted these, a professional wall tie survey can confirm whether your home has failing ties and recommend the best course of action. In most cases, wall tie replacement is required, involving the installation of new stainless steel ties and, if necessary, the removal of damaged or corroded ones.
For professional wall tie inspections and replacements, get in touch with our team today! You can enquire about a wall tie survey, here.
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