Client
Jones Lang LaSalle/Scottish Widows
Value
£190k
Sectors & Services
Buildings Repairs & Refurbishment Heritage & Listed Corrosion Control External Façade Refurbishment Steel Frame Cathodic Protection
22 Hanover Square, a steel-framed office building constructed in the 1920s, exemplifies early 20th-century architecture with thick Portland stone cladding serving as decorative weatherproofing. Over time, the structural steel exhibited corrosion-related deterioration, including cracking and displacement of the stone façade, a condition commonly referred to as Regent Street disease.
In 2008, alongside a full internal refurbishment, it was deemed necessary to install an impressed current cathodic protection system to arrest ongoing corrosion of the steel frame. The project was critical to preserving the building’s historic façade, maintaining structural integrity, and preventing further damage while allowing continued occupancy and ensuring minimal disruption to neighbouring residential properties.
Services undertaken
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Installation of impressed current cathodic protection system
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Supply and fitting of discrete anodes within stone panel joints
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Phased scaffolding and protective sheeting
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Portland stone repairs, matching existing material in texture and colour
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Crack and spalling remediation
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Coordination with internal refurbishment programme
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Structural surveys and monitoring during works
CRL designed and installed an impressed current cathodic protection system using discrete anodes fitted into the joints between the Portland stone panels. Following on-site trials, a phased approach was adopted: Phase 1 addressed floors 2–8 while scaffolding and protective sheeting facilitated safe working and mitigated noise for residents. Phase 2 subsequently covered the ground and first floors. The cathodic protection system was carefully integrated with ongoing internal refurbishment works, ensuring coordination and minimal disruption.
In addition to corrosion mitigation, CRL repaired areas of cracking, spalling, and stone displacement caused by expansive corrosion products. All repairs were meticulously executed to match the existing Portland stone in colour, texture, and profile, making the restored areas virtually indistinguishable from the original. The combination of precise stonework repairs and innovative cathodic protection ensured the long-term stability of the façade while maintaining the architectural integrity of this historic building.
"It was a difficult project carried out in central London on a fully occupied building. We are happy to say that CRL delivered the works efficiently, protecting the structure while respecting building occupancy. Everyone was kept happy and the contract was completed without any H&S incidents."
Michael Balletta | Infrastructure Manager | CRL
The cathodic protection system and sympathetic stone repairs provide long-term structural resilience and significantly reduce future maintenance requirements. By targeting corrosion directly, CRL extended the lifespan of the steel frame and the Portland stone façade, delivering a sustainable, cost-effective solution for the client.
The phased programme, careful planning, and collaboration with the refurbishment team ensured minimal disruption to building occupants and neighbouring properties, demonstrating CRL’s expertise in structural repairs UK and asset management. The outcome is a preserved heritage façade, improved durability, and operational continuity for years to come.
