York House in Chelsea, London is the home to multiple high-end residential apartments. It is a brick clad steel frame building that was constructed in the 1920’s, meaning it was experiencing the effects of Regents Street Disease, such as cracked concrete and a degrading steel frame.

Impressed current cathodic protection (ICCP) was chosen as the best course of action for protecting the structural steel frame, as cathodic protection is non-invasive approach which will not only protect the existing concrete and requires minimal construction, reducing waste and CO2 emissions from this project. The design of the system was undertaken by Structural Healthcare Limited  in collaboration with Declan Duffy Associates (the project structural engineer). ICCP installation and repair of the brickwork was undertaken by Stone Edge Conservation Limited with C-Probe as ICCP specialists.

Product / System Used

LoCem® +point® ICCP system, with CP200 embedded corrosion rate sensors, AchillesICP network management system and AiMS online performance management facility.

In addition LoCem® HLM (heritage lime mortar) was used to infill voids behind the brickwork.

Project Details

+point® anode mortar was installed within the bed joints to a depth of 50mm with the front 10mm being subject to finishing with a heritage lime mortar for aesthetic reasons. All elevations over 9 storeys of the building were protected using ICCP – there were 2 zones of ICCP for each level, equalling 18 zones of protection in total. An additional zone was also implemented into one apartment internally, as extra treatment was needed.

Alongside protection anodes, which would effectively control and prevent corrosion into the future, embeddable sensors were installed allowing ISO12696 performance assessment and service life tracking by monitoring corrosion rate for the long-term. All the data collected by the open network management system uploading to AiMS which stores the data for analysis and allows clients to access to the data when needed.

The use of a geopolymer heritage lime mortar to infill the voiding behind the brickwork provided a low strength empathetic solutions to ensure the brickwork was maintained and provide a path by which the ICCP protection current could be passed to the steelwork.

Project Impact

The repair and protection of York House using low carbon materials, such as AACMs, and ICCP comply with important ESG objectives which focus on sustainable outcomes. Using a non-invasive empathetic method like ICCP minimised any need to deconstruct the existing brickwork, helping to save a significant amount of embodied carbon, while also taking control of the degradation risk to the steel frame which will futureproof the asset.