Wall Ties

Used since the 19^th century, cavity wall designs that incorporate metal wall ties have been used to help improve the thermal insulation of buildings and prevent rain from entering properties.

In recent years, it has arisen that a high number of properties that were built before 1981 are suffering from premature wall tie corrosion. The Building Research Establishment has discovered that wall ties will corrode faster in mortar contain in an external leaf of brickwork. This often leads to lamination where the wall ties expand several times their original size.  As a result of this expansion, buildings are more likely to suffer from structural instability as the wall ties will lift the mortar joints where they are situated.

If you spot horizontal and diagonal stepped cracking in your external wall surfaces this is clear visual evidence of corrosion. The side effect of severe corrosion is distortion and bulging. Externals walls have collapsed after severe gales in certain cases.  Extensive research into wall ties has found that many properties have an inadequate number of wall ties especially around openings, i.e. windows and doors.