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CROSS Safety Report

Structural corrosion in a swimming pool building causes concern

Report ID: 1004 Published: 30 July 2021 Region: CROSS-UK

This report is over 2 years old

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A survey showed severe corrosion of previously repaired steelwork columns adjacent to a public swimming pool.

Key Learning Outcomes

For architects and designers:

  • Swimming pool environments are corrosive, thus steelwork and other structural elements must be appropriately protected

For civil and structural design engineers:

  • Design and detailing must recognise the risks from corrosion in swimming pool buildings

  • Structural elements and connections must be accessible in future for surveys

For owners:

  • Swimming pool buildings must be regular inspected for evidence of structural deterioration and action taken as necessary

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.


This report is from a structural engineer who was commissioned to conduct a visual inspection of a swimming pool building. Their concern is about the stability of the structural steel frame within the pool hall which has undergone numerous repairs to the steelwork over the years.

A problem, according to the reporter, is the state of repairs made to the steel columns. Some of these have had significant corrosion close to the poolside level. An ultrasonic testing report showed that the columns had a considerable loss of section due to corrosion.

The reporter’s firm conducted intrusive opening up works that involved breaking out parts of the concrete floor slab around the bases of the columns. It was discovered that the repair plates had not been welded to the columns in these locations. This, in the opinion of the reporter, would render the repairs ineffective in providing any structural remediation i.e. an alternative load path for the columns around the corroded area.

This, in the opinion of the reporter, would render the repairs ineffective in providing any structural remediation i.e. an alternative load path for the columns around the corroded area

The survey findings were reported to the owner along with a recommendation that the building is unsafe, that it would be uneconomic to repair, and should be demolished. It is understood that the building is now no longer in use.

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.

All structures deteriorate over time and swimming pool environments promote corrosion. Corrosion of steelwork and other structural elements around swimming pools is a common problem and there have been collapses of pool roof structures. Other CROSS reports indicate worrying degrees of deterioration in such structures.

Experience suggests that where corrosion is extensive there may well be hidden areas that are badly affected, and these may govern structural capacity. Hence intrusive investigations are advisable.

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