Cavity Wall Tie Surveys & Remedial Work

Wall ties are a necessary component within a cavity wall construction. Spaced equally throughout the span of the wall, they are designed to tie the internal and external leaves together to help keep the structure safe and stable. 

The image above is from a wall tie survey undertaken by Halton Construction, it shows a severely corroded heavy gauged fish ail metal wall tie, in its ash based mortar bed joint.

Wall tie failure is a common problem, steel and iron are the most regular materials used for wall ties. Failure may be a result of poor workmanship during construction, rusting/corrosion or a chemical reaction where black ash mortar is used. Black ash-based mortar is commonly found in older buildings, the aggressive nature of the mortar due to the high sulphur properties may attack the galvanised coating of the wall ties and the metal, resulting in failure of the ties. 

The images show wall ties that were taken from remedial wall tie works, undertaken by Halton Construction. As you can see from the images the level of corrosion is varied, tie 2 has expanded significantly showing a higher rate of failure. A corroding metal tie may expand up to 7 times its original size, this results in many defects within the structure.

Halton Construction can provide the necessary high-quality services required, in order to investigate suspected wall tie failure. The condition of wall ties can only be judged by visual inspection of the metal tie. This can either be done by using an advanced optical borescope or by removing the brickwork or mortar from the external leaf of the wall. A detailed survey report will be produced, with recommendations regarding the condition of the wall ties and any remedial works.