Wall Tie Replacement

What is Wall Tie failure?

Wall Tie failure is the corrosion of the protecting coating of the wall tie. Wall ties are fasteners across a cavity wall to hold the two leaves together. They are made of stainless steal or galvanized steel wire or strip, or of plastics, featuring a twist or bend near the middle to form a drip so that water cannot pass.

Properties constructed after 1920 usually have cavity walling. Cavity walls are formed in two leaves of brickwork. Generally there is an outer leaf of 100mm thick brickwork, a 50mm cavity and an inner leaf of approximately 100mm. These two leaves are tied together with wall ties and the ties are usually spaced apart at 900mm horizontally and 450mm vertically. The wall ties are steel and galvanized. Before the revision of the 1981 British Standard BD 1234, this coating was a thin layer of galvanizing and not adequate to prevent corrosion occurring, therefore leaving the ties exposed to potential failure.

How do you know if you have a problem?

You can identify where wall ties have corroded by signs of jointing cracking on external renderings in position of wall ties and, in more serious cases, bulging of the outer leaf where the ties have corroded to such an extent that the walls are no longer tied together. This could result in the outer leaf collapsing, especially in exposed locations.

How we can help

To determine the condition of the wall ties it is necessary to carry out a thorough inspection using a wall tie locator to determine the pattern and position of the existing ties. To establish the condition of the ties our inspection would normally involve removal of certain bricks where the ties are located or where there is visible damage. Visual inspections usually take place and a decision made on their residual life. If the ties have corroded our report will recommend a suitable replacement wall tie. The existing ties will need to be isolated from the outer leaf to prevent further damage occurring.