Behind the Scenes : 8 Bishopsgate
Wednesday, 10 May 2023
With less than a month until Practical Completion and with the building still a hive of finishing and commissioning activities the CAF were privileged to be given a tour of 8 Bishopsgate by Ollie Tyler of Wilkinson Eyre.
Mitsubishi's latest addition to the London skyline is at the centre of the City at the corner of Bishopsgate and Leadenhall. Began in 2013 with the acquisition of two neighbouring sites the following years saw the City continue its inexorable evolution upwards with 22 Bishopsgate by PLP consented at 62 storeys, and 40 Leadenhall by Make at 40 storeys. In response it therefore made sense to grow 8 Bishopsgate from the original consent at 40 storeys up to 50 to provide a stepped massing across the three projects.
This decade long journey also permitted the evolution of several other design features. The building presents itself as an amalgam of 3 distinct forms; an 9 storey stone box, a 26 storey braced box, and rising above it at 20m wide, a slender tower topping out at 50 storeys. The staggered massing of three elements accommodates floorplates varying from 20,000 sqft and 15,000 sqft up to 8,500 sqft. as you ascend.
The clever structural resolution by Arup gives rise to an elegant architectural expression in that the top 24 storeys take their bracing from the box below using just the in-situ core located on the north elevation for stability. Unusually for a core the north wall here benefits from glazed openings framing tantalising glimpses out to works by Lutyens and Rogers amongst others. The rest of the building is skilfully clad in a 200mm deep CCF [closed cavity facade] facade formed with semi-low iron glass. Tyler and his team’s efforts to keep the outer pane dead flat have paid off with incredibly crisp detailing and the flattest of flat facades. The other distinctive feature of this facade is that these units are at 3m widths giving a generous and open feel the building’s skin.
Added drama comes form the 26 storey box cantilevering out to the pavement's edge, and whose slender solar fins are cropped along the line of the bracing to accentuate the structural gymnastics at play within. Further interest is provided by a terrace for occupants at level 11. But what steals the show is the public viewing gallery at level 49. This floor plate benefits from stunning views to the panorama of the Thames beyond. The feeling on arrival is one of being amongst a series of chess pieces with the sensation that the neighbouring Cheesegrater and Walkie Talkie are within touching distance.
Additional public engagement comes in the form of the double storey entrance off Bishopsgate, where flanking meeting and town hall spaces are provided at mezzanine level. The security line is pushed back to allow the public access into these areas. A facetted timber ceiling along with a glazed balcony are all detailed with the Wilkinson Eyre customary aplomb.
On the main floors the fit out spec includes acoustic rafts at 2.785m above FFL. Ceilings are otherwise open with services on show making the most of the 3.850m typical floor to floor heights. The structural bays extend to 12m, but vary around the building according to how the plan responds to the site constraints. Meanwhile the potential embodied CO2 implications of these relatively long spans are offset by engineering the beam flanges to reduce according to structural requirements rather than architectural alignment. Something that can and should be done across the industry. The building is on course for BREEAM Outstanding and an A EPC rating.
We all felt this was a very well thought out and crisply detailed building and with some of its best spaces directly accessible to the public, so a welcome addition to the City. As well as Wilkinson Eyre and Mitsubishi, credit must also go to Stanhope, the Development Managers, and the rest of the design and delivery team.
Double height entry to 8 Bishopsgate
Thanks to Ollie for hosting and a return visit in a couple of months to see see the finished building would be much appreciated by CAF!
Mike Taylor words and photos
Member of City Architecture Forum