(Cavity) Wall Tie Replacement

As many as 2 million properties in United Kingdom may be suffering Wall Tie corrosion or failure and are in need of remedial stabilisation.

The problem is often made worse when insufficient Wall Ties have been used during the construction.

The absence of sufficient and effective wall ties will ultimately result in the structural failure of the wall and probable collapse.

Wall ties that have begun to corrode expand up to ten times their original thickness; this process is the cause of the step cracking associated with wall tie failure.

The cause of Wall Tie failure

The cause of wall tie failure is the lack of quality control during the construction phase which meant that often too few ties were fitted.

Prior to the 1930s wall ties were not galvanised, meaning no protection against corrosion. Galvanisation standards were also reduced between 1964 and 1981, meaning that millions of substandard wall ties were produced for 17 years.

Coastal locations with salt-laden driven rain also cause wall ties to corrode.

Identifying Wall Tie failure

Look for :

Horizontal cracking at regular intervals to the external mortar joints typically around windows and doors.
Outward bulging of the affected walls.
The lifting of roofs as a result of the lamination of the wall ties due to corrosion.
Internal cracking that corresponds with external cracking.

The property needs to be inspected by a competent remedial surveyor using a metal detector and an endoscope to locate and examine the existing ties. Where replacement is necessary the surveyor will select from a range of stainless steel mechanical or resin fixed ties to suit the type and condition of masonry involved.

It is most important during the wall tie replacement works that the original ties are located and isolated to stop any further expansion that will lift the brickwork any further.