What is the purpose

Of cavity wall ties?

Cavity wall design, which uses metal wall ties to tie the inner and outer leaves together, has been in use since the beginning of the nineteenth century. The purpose of cavity walls is to prevent rain penetration and to improve thermal insulation.

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typical cavity wall ties that are prone to rust
horizontal crack in brickwork caused by corroded wall ties

What happens

When the wall ties corrode?

Over recent years, it has become apparent that a high number of properties built before 1981 are suffering from premature wall tie corrosion. Pull out testing can identify where the issue lies and will determine the solution required.

Latest research by the Building Research Establishment, has found that wall ties corrode faster in the mortar within the external leaf of brickwork, leading to oxidisation, where they will expand to several times their original size. This expansion will cause structural instability by lifting the mortar joints where they lay.

Visual evidence of wall tie corrosion can be seen by horizontal and diagonal stepped cracking to external wall surfaces. If corrosion is severe it will lead to distortion and bulging. In some cases external walls have collapsed during gales. Research has also found that a high percentage of properties inspected had an inadequate number of wall ties especially around openings, i.e. windows and doors..

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Wall tie


After identifying existing wall ties with the help of a metal detector, they are either removed or treated and isolated.

Pilot holes are then drilled through the brickwork, at pre-determined intervals, and helical wall ties are then hammer driven through both skins. Being helical, with a high fin profiles, the ties corkscrew into the masonry tying the two skins together. Because they are made from high-tensile stainless steel, they do not rust.

The holes are then filled with colour-matched brick repair mortar to provide an invisible repair.

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Drilling pilot hole in brick wall for cavity wall tie


Call us for help with any of these

Common structural defects, issues and problems

Crack Repairs
Bay Window Repair
Concrete Repair
Micro Piles


To trust ASRS

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Free Quotation

We offer free site visits to both domestic and professional clients to assess the problem and propose the appropriate repair programme, tailored to suit the specific needs of the project.

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Helifix Approved

ASRS are approved installers of the Helibeam System, offering cost effective, non-disruptive and concealed solutions to all aspects of remedial masonry stabilisation.

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Skilled Workforce

Our skilled installation teams are trained and experienced in all aspects of masonry repair. They have been trained to the highest standard in every installation process to cover all H+S requirements.

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With most of our design and installation specifications we are proud to offer a 10yr indemnified guarantee on Helifix repairs and Micro Piling. We offer a 25yr guarantee for Wall Tie replacement.