Skip to main content

CROSS Safety Report

Collapse of infill wall panel

Report ID: 511 Published: 1 July 2015 Region: CROSS-UK

This report is over 2 years old

Please be aware that it might contain information that is no longer up to date. We keep all reports available for historic reference and as learning aids.


A blockwork infill wall panel approximately 4m wide and 9m high between two building collapsed in high winds.

Key Learning Outcomes

For construction professionals:

  • Quality assurance and competent supervision on site can help to ensure that the structures including infill wall panels are built in accordance with the design

  • Effective communication of essential design information and details in an accessible form to tradespeople working on site can also ensure the works are in accordance with the design intent

For civil and structural design engineers:

  • Adequate design details and specifications should be provided for bespoke wall panels to ensure there is no ambiguity as to what detail should be applied to the construction

  • The type of wall tie, method of fixing, spacing and tie frequency should be carefully considered and clearly conveyed on the construction drawings

Full Report

Find out more about the Full Report

The Full Report below has been submitted to CROSS and describes the reporter’s experience. The text has been edited for clarity and to ensure anonymity and confidentiality by removing any identifiable details. If you would like to know more about our secure reporting process or submit a report yourself, please visit the reporting to CROSS-UK page.


A blockwork infill wall panel approximately 4m wide and 9m high between two buildings, A and B, collapsed in high winds. An investigation was carried out by the reporter's firm in conjunction with other parties and the main findings were:

  • Frame cramps (wall ties) remained fixed in place on the A side of the failed panel, whereas they were torn from the steel on the B side

  • The wall panel was subject to significant wind load, predominantly from the rear, funnelling down a service corridor, but potentially also from suction on the other side

  • Side A frame cramps (wall ties) had failed, and the wall slipped off them, possibly due to fatigue and buffeting, although most likely due to lack of ties. Ties were installed at 450mm centres rather than 225mm.

  • Embedment of ties was 45mm rather than the specified 50mm minimum

  • Shot fired ties used, where tec / self-tapping screw fixings are recommended by manufacturer (although the use of shot fired ties is industry norm)

  • There was no bed /joint reinforcement

  • Lack of specific architectural detail

Recommended action to be taken in future, says the reporter, are:

  • Where there is a bespoke wall always ensure that there is a design detail / specification, so that there can be no ambiguity as to what detail should be applied to the construction. Do not rely on standard details which may be sufficient for more normal sized walls.

  • Consider the type of wall tie, the method of fixing, the spacing and frequency. Clearly defined details should be incorporated into the project inspection and test plan, with sign off at key stages.

  • As a general comment - practitioners should always ensure that inspection regimes are thorough, robust and documented

Expert Panel Comments

Find out more about the Expert Panels

Expert Panels comment on the reports we receive. They use their experience to help you understand what can be learned from the reports. If you would like to know more, please visit the CROSS-UK Expert Panels page.

There are no Expert Panel comments on this report. The Expert Panels are only asked to comment on selected reports. These are normally reports where there is an opportunity for them to help you understand what can be learned from the report.

Submit a report

Your report will make a difference. It will help to create positive change and improve safety.

Our secure and confidential safety reporting system gives professionals the opportunity to share their experiences to help others.