The firm claims this reuse of major steel sections on the same project is a first for construction, allowing some 96% of the steelwork to be retained on the complex rebuild.

Developer Castleforge has appointed McGee to carry out deconstruction works for the 1 Golden Lane project at Cripplegate House in the City of London.

McGee has used its carbon engineering expertise to develop an approach that allows the deconstruction and de-fabrication of the existing structural steelwork from the 1980s building, allowing it to be recertified, refabricated and reused in the new proposed structure.

This pioneering approach is being used because cuts more carbon emissions than other structural solutions on the project that involves retaining one elevation of the 1894 original building facade.

Around half the original building will be retained with substantial demolition and rebuild of the remaining offices behind.

The proposed refabrication involves ribbon cutting the existing beams to increase the stiffness of section, something which has never previously been done on a reused steel section.

McGee worked with the designers, industry bodies and Castleforge to demonstrate the viability of steelwork reuse in this scheme to reduce the carbon emissions and ensure the protection of the original building.

In addition, McGee will undertake structural demolition of some existing RC slabs, the roof and the façade of the building.

Prosed new upper levels of repurposed Cripplegate House taking project to 12 storeys

Seb Fossey, group managing director, said: “This is the first time that any project in the UK is targeting exact steelwork sections to be deconstructed, de-fabricated, recertified and refabricated for use in the redevelopment of the same site.

“It is our hope that by successfully delivering this scheme it will demonstrate that technical solutions around steelwork reuse are commercially viable for future schemes in The Capital.

“I’m delighted that Castleforge has put their trust in the experience of our team to deliver this UK first. We are committed to enabling lower carbon solutions through our high value engineering solutions.”

Oliver Vickerage, Development Manager at Castleforge said: “1 Golden Lane is set to pioneer innovation in sustainable development of stranded City assets.

“Our alignment on a RetroFirst approach has enabled the retention of 96% of the existing structure. The innovative ribbon cutting algorithm developed as part of this project, enabling the augmentation of steel sections to the required depths will massively increase the opportunity for steel re-use in a market expectant of symmetry and clean lines.”

The professional design team includes: Hawkins/Brown (Archietct); London Structures Lab (Structural Engineering); Arup (Services Engineering, Energy/Sustainability, Air Quality, Circular Economy); Trigon (Fire Safety Engineering); Blue Sky Buildings (Construction Management); and Gardiner & Theobald (cost management).