Failed wall ties: how to spot them and what the repair involves
Rusting wall ties leave a tell-tale signature in the brickwork. Catch it early and the repair is routine, not dramatic.
What wall ties do
In a cavity wall, metal ties bridge the gap and tie the outer and inner leaves together so they act as one. In houses built up to the 1980s, those ties were often mild steel. Over decades they rust, and as rust takes up more room than the original metal, they expand and lift the brickwork.
The signature to look for
Failed ties leave an unmistakable pattern. Because the ties sit at regular intervals, the cracking appears in regular horizontal lines along the mortar beds — typically every five or six courses — and the outer leaf may bulge outwards.
- Regular horizontal cracks in the mortar beds, evenly spaced up the wall
- Outer walls bowing or bulging outward
- Cracking worse on exposed, weather-facing elevations
- Lifting or stepped cracking around window and door reveals
The repair
The fix is well-proven and far less disruptive than it sounds. New stainless steel ties are resin-fixed or mechanically driven through the outer leaf into the inner, on a grid set by survey. The old ties are isolated so they cannot do more harm, and the cracked beds are repointed to match.
It is done from outside, the house stays lived-in throughout, and stainless ties will not rust, so it is a permanent repair rather than a patch.
Related questions
Are failed wall ties dangerous?
Left long enough they can let the outer leaf bulge and, in severe cases, become unstable. Caught at the cracking stage, replacement is straightforward and prevents it ever getting that far.
How long does wall tie replacement take?
Most houses are done in a few days, worked from outside with the property occupied throughout. The exact time depends on the wall area and how many ties the survey grid calls for.
Ready to take it further? See our structural brickwork & repairs service.