Client
London Underground
Value
£120k
Sectors & Services
Buildings Repairs & Refurbishment Heritage & Listed Corrosion Control Steel Frame Cathodic Protection Projects
Gloucester Road underground station, designed by Leslie Green and constructed in 1906, features two above-ground buildings, one of which is steel-framed and clad in glazed terracotta blocks. The steel frame was originally intended to support offices above the station, which were never built, and over the years water ingress at roof level led to corrosion, cracking, spalling, and up to 10mm distortion of the terracotta façade.
Previous mortar repairs and paint had concealed the worst deterioration, creating a pressing need for a sensitive restoration scheme that would stabilise the structure, arrest corrosion, and maintain the operational use of the retail units beneath while preserving the building’s historic appearance.
Services undertaken
-
Supply and installation of discrete platinised titanium anodes
-
Installation of continuous strip (ribbon) anodes where required
-
Drilling and bedding anodes with graphite grout
-
Cable connection to transformer
-
Selective cleaning and protective coating of steelwork
-
Replacement of broken terracotta blocks
-
Mortar repairs to façade
-
Leak and rising damp remediation
-
Survey and monitoring of steel corrosion
CRL was awarded the contract to design, supply, and install a cathodic protection system to arrest ongoing steel corrosion and preserve the terracotta façade. Initial investigations included selective opening of damaged areas, revealing up to 3mm rust build-up and cracking caused by steel expansion. Endoscopic surveys identified steel that required protection versus sections that could be left untreated with cleaning and protective coatings. Discrete platinised titanium rod anodes were bedded into drilled holes with graphite grout, staggered on either side of the frame at 250mm centres, and connected via cabling to a transformer. Where masonry casings needed rebuilding, continuous strip (ribbon) anodes were employed to provide effective protection.
This approach allowed retention of existing shop tenants and minimised disruption, with properties vacated for only ten weeks during the seven-month programme. Works also addressed leaks and localized rising damp, with damaged terracotta blocks replaced as necessary, and mortar repairs made to maintain façade integrity. The combination of cathodic protection, selective steel treatment, and terracotta replacement provided a technically robust solution while respecting the building’s heritage significance and operational requirements.
"This was the first use of cathodic protection to the complete steel framed building facade in the UK and CRL are proud to have been involved"
Steve Jones | Southern Regional Director | CRL
The cathodic protection system significantly extends the life of the steel frame and reduces future maintenance requirements, safeguarding both structural integrity and the historic terracotta façade. By targeting corrosion directly, CRL provided a long-term, sustainable solution that avoided full façade removal, minimising disruption to tenants and the public.
The careful planning and collaboration with conservation specialists ensured the works respected heritage values while delivering a cost-effective, technically resilient outcome. This project highlights CRL’s expertise in structural repairs UK and asset management, demonstrating an ability to combine innovative engineering solutions with heritage conservation and operational continuity.
