1 Golden Lane, formerly known as Cripplegate House, is an office development by Castleforge. The extension and refurbishment of the existing building are designed by Hawkins/Brown.

Castleforge’s ambition is to create a cutting-edge office space that will be 20% lower embodied carbon than the London office benchmark. The reuse of steel will achieve this. London Structures Lab have developed a world-first concept to take existing steelwork from the building, ribbon cutting it to increase the depth of the sections and then placed back in the new vertical extension.

Using the Ribbon cutting method, 40% more steel can be reused in the new build from the existing stock. This design approach has enabled the services to be distributed evenly and consistently to create a harmonised ceiling line. This removes the challenges of visually integrating newly framed office spaces with retained structures.

McGee collaborated with the Client team, and industry bodies, to demonstrate the viability of steelwork reuse in this scheme to reduce the carbon emissions and ensure the protection of the original building. This included deriving a methodology to deconstruct the existing sections and demonstrate how testing and recertification could remove all the perceived blockers in reusing existing steelwork.

McGee has used its carbon engineering expertise to develop an approach to deliver certainty in removing the existing structural steelwork from the 1980’s building, allowing it to be recertified, refabricated and reused in the new proposed structure. McGee removed the perceived risk points to create a procurement route to unlocking this opportunity.

This pioneering approach enables the proposed extension of the building to emit less carbon than other structural solutions and is an example of its commitment to delivering innovative technical solutions for complex schemes.

Oliver Vickerage, Development Manager at Castleforge said: “1 Golden Lane is set to pioneer innovation in sustainable development of stranded City assets. Ambitious targets for best-in-class accreditations, including BREEAM Outstanding, are being taken a step further through new opportunities for fabric retention, material re-use and the promotion of circular economy principles.