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STO Building Group Projects - Twenty St. James's Street
Structure Tone is a global leader in construction management and general contracting services with offices located in the US, UK, and Ireland. Founded in 1971, the company is among the world’s top twenty construction companies worldwide, responsible for more than $3.5B in annual construction volume.
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Twenty St. James's Street

The complex refurbishment of the commercial office building at 20 St. James’s Street is now complete, creating a high-quality, modern and sophisticated West End office building.

As part of their mission to revitalise properties across Central London, Grafton Advisors, as property adviser to the largest Central London fund, WELPUT, enlisted the help of Structure Tone to upgrade and reposition Twenty St. James’s Street. Over the course of 18 months, Structure Tone worked collaboratively with ORMS, WPP, HTS and the supply chain to deliver 10 floors of top quality office space and a striking reception area with signature artwork. This artwork includes an 18m brass veil, manufactured by a specialist contractor and forming the centrepiece to the development.


The project involved a transformative structural refurbishment. The existing cores have been removed from the centre of the building, which allows the new design to maximise lettable floor space by consolidating the cores to a single core at the rear of the floor plate and infilling the existing atrium.

External view of the new repositioned Twenty St. James's Street


Other upgrades to the building include installing three new lifts, restoring the existing façade to also include new double height street-level glazing and adding a skylight to the lower ground floor.  A new lavish reception better fits contemporary clients’ expectations, as do premium amenities and facilities on each of the 10 floors, and bicycle/showering facilities in the basement.


Throughout the project, Structure Tone was careful to protect the adjacent landmark Mayfair cigar shop so that business remained unaffected by the works. At the topping out in May 2017, our guest of honour was the Mayor of Westminster.

The owner of Twenty St. James’s Street is The Ryder Street Unit Trust. The project team included Grafton AdvisorsGo to South ProjectsGo to PayneGo to ShreevesGo to to and Hayne Tillett SteelGo to


Ryder Street Unit Trust


20 St. James’s Street, London






December 2016 – June 2018

Project Manager

City South Projects


Watkins Payne / Heyne Tillet Steel

Quantity Surveyor

MPG Shreeves

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