:: Wall Ties ::

For some 60 years now, modern buildings have been built on the cavity wall tie principle, the resultant structures are rigid, well ventilated and sound, provided that the metal wall ties tying the two leaves of brickwork together remain firmly in place.

However an increasing number of buildings both new and old have been found to have wall corrosion. It is estimated that some 10 million dwellings with cavity walls will be at risk at some time in the future.

This is when the trouble starts, trouble that means worry and expense for the private owner and big bills for the local authority if it is a public property. The main problem with ties used prior to 1981 is that there was not enough protective coating applied. When a mild steel tie starts to corrode it expands up to four times its original thickness. The result is weakening of the structure, cracking of the mortar joints in the outer leaf, with a possibility of water penetrating the inner leaf and inside the building and at worst external walls collapsing during strong winds.

Example of unsecure external wall which collapsed during strong winds

Possible signs of walls ties corrosion may be observed as follows:-

• Gaps in the mortar joints visible with the naked eye horizontally and vertically.
• Wide mortar joints vertically 18" (450mm) apart.
• Movement of brickwork at door and window reveals.
• Bulging of brickwork or rendering.
• Evidence of roof structure lifting.

Wall tie failure is a situation that can be treated, it will become a problem if left untreated.

More about Wall Tie problems