Cavity wall ties are essential components in many UK homes, playing a crucial role in maintaining the stability and structural integrity of the walls. When these structural links fail, several problems can arise, compromising the safety and comfort of the property. Understanding the early signs of a wall tie issue can help to prevent further damage and ensure timely intervention.
This comprehensive guide is designed to help identify potential signs of cavity wall tie failure, understand the underlying causes, and advise on what steps to take to address the issue.
What Are Cavity Wall Ties?
To understand the signs of failure, it’s important to understand what cavity wall ties are and their purpose. Cavity wall ties are used in buildings with cavity walls, a construction method prevalent in homes built post-1930s. These walls comprise two layers: an inner leaf (usually brick or blockwork) and an outer leaf (often brick). Cavity wall ties are unseen components that tie the internal two leaves of the cavity wall together, tying the load-bearing inner leaf to the outer leaf, creating stability and holding the wall in place. During construction, they are embedded in the mortar joints, forming a crucial link between the two leaves. The styles, shapes, and materials used for cavity wall ties have evolved, with older materials like plastic and galvanised steel sometimes leading to problems due to corrosion.
Why Do Cavity Wall Ties Fail?
Cavity wall ties can fail for several reasons, and understanding these causes can help prevent further issues:
- Corrosion: This is the most common cause of failure. Older wall ties, particularly those made from galvanised steel, can corrode over time, especially in damp or exposed environments.
- Material Failure: In some cases, the ties themselves may be faulty or made of unsuitable materials that degrade over time (e.g. early plastic ties).
- Age of Material: Mild steel with a thin galvanised coating can degrade over time.
- Construction Defects: Improper installation during construction can also lead to premature failure. From not being embedded properly in the mortar to spacing issues. If too few ties are used or they are not spaced correctly, it can weaken the walls. Using the wrong type of tie can also cause problems, as different wall ties are designed for specific walls and cavity widths; using the wrong ties can lead to failure.
- Structural Movement: Natural ground movement over time can put stress on the wall ties.
- Environmental Factors: Significant rain and wind can increase moisture penetration and put stress on the wall ties.
Signs of Cavity Wall Tie Failure
Recognising the signs of cavity wall tie failure is crucial for early detection and repair. Here are some common tell-tale signs to watch for:
- Horizontal Cracking: One of the most common signs of cavity wall tie failure is horizontal cracking in the external mortar joints. These cracks often appear at regular intervals and follow the line of the wall ties.
- Bulging Walls: Failing wall ties can cause the walls to bow or bulge, indicating a loss of structural support. This is particularly noticeable on long, unsupported walls.
- Damp Patches: Dampness can penetrate through the walls to the interior wall due to failing ties, which can create a pathway for moisture ingress.
- Loose or Displaced Bricks: In severe cases, wall tie failure can lead to bricks becoming loose or displaced, posing a safety risk.
- Internal Cracking: While less common, cracking may also appear on internal walls.
It’s worth noting that these signs may also be caused by other structural issues. If you’re concerned about the condition of your wall ties, it’s crucial to consult with a property preservation specialist for a professional assessment to determine the best course of action.
The Dangers of Ignoring Cavity Wall Tie Failure
Ignoring failing cavity wall ties can have serious consequences and worsen the problem. Without treatment, this can lead to
- Further structural damage to the walls, potentially requiring extensive and costly repairs.
- Increased dampness and potential for mould growth, which can affect the health of occupants.
- Compromised safety of the property, as weakened walls may become unstable.
Addressing cavity wall tie issues promptly and effectively is vital to maintaining the long-term health and stability of your home. A professional surveyor will use specialised equipment to inspect the condition of the wall ties within the cavity wall.
Prevention and Long-Term Solutions
While some factors like age and environmental conditions can contribute to wall tie failure, proper installation and the use of suitable materials are essential for prevention. Modern stainless steel wall ties offer superior corrosion resistance and longevity, making them the preferred choice for replacement.
What to Do If You Suspect Cavity Wall Tie Failure
Cavity wall failure is a serious issue that homeowners need to be aware of. Understanding the signs and causes, and by taking prompt action, you can protect your property and ensure its long-term structural integrity. Don’t wait until it’s too late! If you’re concerned about the condition of your cavity wall ties, contact a professional for a thorough assessment.
If you suspect cavity wall tie failure, it’s crucial to seek professional advice. A qualified surveyor will assess using specialised equipment to inspect the wall ties and the affected walls, A thorough inspection will include examining the condition of your wall ties and recommending the appropriate course of action.
