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CROSS Safety Report

Lightweight steel roof partial collapse

Report ID: 383 Published: 1 April 2014 Region: CROSS-UK

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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 hall constructed from thin cold rolled steel sections riveted together started collapsing when tiles were loaded on one side only.

Key Learning Outcomes

For construction professionals:

  • Quality control and competent supervision on site can help to ensure that the structure is built in accordance with the design
  • It is good practice to carry out a risk assessment and method statement (RAMS) for all construction activities. This can ensure the sequencing of work activities are properly considered and planned.
  • A structure should be checked to ensure it has the required capacity to accommodate temporary construction loads

For civil and structural design engineers:

  • Asymmetric loading conditions should be considered, particularly for roof structures
  • If a structure has not been designed for temporary construction loads, clearly highlight this on the drawings

Full Report

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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 hall constructed from thin cold rolled steel sections riveted together started collapsing when tiles were loaded on one side only. The reporter says that joints were poorly detailed/constructed with lack of end distance to the rivets and eccentricities. No effect of the dominant openings construction or of the lateral loading/stability seems to have been considered. No asymmetric loading was considered.

Expert Panel Comments

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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.

Poor construction may have stemmed from design, or detailing, or fabrication or a combination of these factors. Lightweight framing is particularly susceptible to minor imperfections which can have a greater effect than in frames with larger and heavier members.

However, the input of a competent designer is not lessened by the fact that the members are thin and slender; indeed, good engineering skills are needed when margins are tight. The lightweight steel industry is relatively new and diverse and needs to have properly accredited persons and organisations to carry out work. Caution is needed.

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