20 St James Street, London, SW1A
City South Projects Ltd
9 months and 2 weeks
City of Westminster, SW1A 1ES
Location & Overview
Our works at 20 St James Street, an office block in Mayfair close to the Ritz Hotel, were completed in two stages. We conducted soft strip of the site for ten weeks, then undertook the demolition for seven months.
Work, Challenges & Solutions
Our works included cut and carve demolition, during which we removed lift shafts and staircases to make the development more user friendly, with 70% of the building retained. Asbestos removal was completed throughout the building during the soft strip phase of works, with drilling and mini piling also carried out. Extensive temporary works were installed, which included propping and ground anchors.
Our soft strip works were vast, encompassing the removal of all internal non load bearing partitions and internal doors, all suspended ceilings, M&E plant and all lifts and lifting machinery. We retained the façade and approximately half of the building, effectively removing the centre of the building. We also de-clad the internal atrium and unbounded screeds to a maximum depth of 50mm, isolated services and erected scaffolding inside to remove the atrium.
Our temporary works included back propping, ground anchors, balance beams, the propping of vaults and sway bracing. Steel propping was put in place to prevent the building moving. A temporary steel gantry was installed, which the offices were situated on, and party wall restraint, slab retention, roof back propping, hoarding and basement excavation were also enacted.
We encountered issues during the piling section of works, as there were obstructions in the ground where we had initially planned to carry out the piling for a new lift pit installation. We drilled to 6m but had to abandon our works temporarily due to the obstructions. Our structural engineers redesigned the pile layout, thus omitting the issue and allowing works to continue, allowing for mini piling of 18 450mm diameter piles to be carried out, to a depth of 3m. We drilled to a depth of 28m for new lift and stair cores. Innovative engineering was also shown on site by the use of balance beams and ground anchors to enable support to the main party wall while demolition was occurring.
Our site shared its footprint with a cigar shop named JJ Fox, and we ensured throughout our works that we maintained a positive relationship with them. The shop had historical significance, as it was known to have been frequented by Napoleon Bonaparte and Winston Churchill, so we made sure to liaise with the owners extensively during our works. We spoke with JJ Fox daily to inform them of our works and assisted them as they did work in their basement to create new offices, taking away old furniture and racking. Their air conditioning and extractors were also protected during our soft strip works, and we maintained the shop’s fire escape routes and fire alarm system.
In correspondence with the site’s proximity to a busy road near Mayfair, we enacted seven parking bay suspensions to accommodate welfare cabins and muck away.
St James site achieved a CCS Gold Award, and a 93.10% rate of diversion of waste from landfill. 40 tonnes of non-ferrous scrap were recycled, along with 2,960 tonnes of reinforced concrete, 10 tonnes of fixtures and fittings and 72 tonnes of muck.