Recreating a Quarry Wall Through a Lobby Installation at 100 Bishopsgate
An earlier version of this article appeared in the Fall 2020 issue of Building Stone Magazine.
100 Bishopsgate is a development of two mixed-used buildings in London’s financial district. On the walls of the ground floor and lobby, a wide range of Lasa White marble from Carrara, Italy was used to welcome visitors to the complex.
Designed, by Allies and Morrison and Arney Fender Katsalidis (AFK), the 100 Bishopsgate site spans between St. Ethelburga’s Church and Camomile Street, with Clerks Lane separating the two portions. The main 55-story tower is anchored by five contiguous podium floors, each encompassing 44,000 square feet of space, while the lobby alone spans 17,000 square feet.
“While towers are sometimes conceived as freestanding buildings, often disassociated from context, 100 Bishopsgate is designed to contribute to the matrix of the city fabric and be firmly embedded within it,” said Graham Morrison, cofounder and partner of Allies and Morrison in London. “Responding to the geometries of the site and adjacent buildings, its form transitions from a parallelogram at its base to a rectangle crown. Contrasting façade textures relate to this orientation, each separated by articulated corner details.”
“It is a project with an important urban dimension,” added Earle Arney, director at AFK in London, who worked alongside Morrison for five years on the project. “A newly created half-acre of public realm, enlivened with restaurant and retail amenities, provides completely new pedestrian access between Bishopsgate, St. Mary Axe, and Camomile Street to the north. Part of this development includes 15 St. Helen’s Place, whose south façade has been retained as part of a private courtyard; the new articulated façade to the north providing entrances to the office lobby and a new gym.”
On the ground floor of the main tower, intricately designed stone walls, elevator cabs and shafts, and an expansive reception desk were crafted using Lasa White marble from Euromarble in Carrara, Italy. The stone demands attention from all angles when entering the building.
“Suiting the prominence of its site, how the new tower meets the ground has been a fundamental consideration to the design,” Morrison said. “A generous, triple-height reception space opens out onto Bishopsgate and the new pedestrian routes created by the project. Externally wrapped in glazing, the reception’s interior is defined by dramatic Lasa White marble that wraps around the building’s lift cores, giving a contemporary and dignified presence to a significant internal space. Visible at street level, it also helps to give expression to the building’s prominence by announcing its presence at ground level.”
Recreating the Quarry Wall
Morrison shared that the design concept for the lobby “expresses the core as the grounding element,” while the floors and ceiling are expressed as “plates that radiate from this solid core.” He explained: “This concept considers the light and dark of the three key interior elements: floor, walls, and ceiling. The core has been designed to appear as if a solid block of marble was extracted from a quarry and displayed from floor to ceiling. The floor is a continuous stone surface from the paving of the exterior public realm to the interior with black granite laid in a rectangular module. The floor junction with the core is separated, allowing the marble to appear as if it emerges from the ground as a solid form. The primacy of the core is dominant and detailed to express the way it pierces both floor and soffit to reach each level [lower, middle, and upper]. To reinforce this, each block of tightly jointed white marble has been selected and placed to create a continuous diagonal grain of gray veining, which turns seamlessly at each corner.”
All of the walls—specifically the lobby’s feature wall, which is engraved with “100” to give subtle prominence to the building’s address, were all vein-matched to convey the solid look that Morrison descries, a feat that took a lot of time and planning to achieve. The stonework was completed by the London-based stone specialist contractor, Szerelmey, Ltd. “The wall cladding installed is the result of an interesting and unusual process,” said John Guest, senior contracts manager at Szerelmey, Ltd. “Lasa is a white marble with a distinctive, smoky gray vein pattern. The architect’s design intent was for the central core of the reception lobby to appear as though cut from a single, huge block, with the veining appearing to run at least 30 degrees on the front and back core walls, and horizontally on the sides and lift lobby walls.”
Guest explained that this was achieved by selecting blocks for their background color and general appearance before they were transported from the Italian Alps to Tuscany. “At the factory, the blocks were slabbed and photographed as they passed through the honing line. This allowed for a jigsaw of pieces to be created by positioning the stone cut size for each piece, according to its veining, thus creating the illusion of long, sweeping marble veins.”
To add texture to the diagonal, striated pattern, a waterjet finish was applied to the marble. “These walls express the monolithic form and the marble has a natural, though uniform, pattern and minimal 2-mm joints,” Morrison said. “As the marble turns into the lift lobbies, the pattern becomes horizontal to express the ‘cuts’ into the monolithic block, and the finish becomes eggshell to express the cut.”
More than 16,000 square feet of the Lasa White marble was supplied by Euromarble—14,440 square feet of 3-cm-thick panels for the walls and 1,700 square feet of cut-to-size pieces with honeycomb backing for the elevator cabs/shafts and reception desk.
“As we usually do in our projects, we bought the material directly from the quarry in blocks and slabs. Then we developed the overall marble design of the cladding, trying to rebuild the face of the quarry in all its own different faces,” said Euromarble’s owner, Roberto Canali. “This idea, and then the proposal, came during the visit to the quarry, where we realized how beautiful the natural veining was with its different inclinations. The goal was to obtain the monolithic effect of the marble, as per the natural pattern completed by Mother Nature.”
The “monolithic effect” of the marble can especially be observed in the elevator shafts, where the continuous veining was carried to give the appearance of solid marble being carved to reveal the elevator doors. Large-format marble panels, which span 1200x1960mm (~4×6.5 feet), convey the appearance that the stone has been pushed away from the monolith when the elevator doors open, providing an interesting transition from the walls.
The reception and landlord desks, which are positioned directly in front of the engraved feature wall, also embrace this monolithic design concept, and were created to mirror the core-like wall. According to the architects, the main reception desk was designed as a “solid marble block penetrating the floor with a perimeter recess.” The top and sides of the reception desk are carved out of solid marble, so visitors touching the desk are conscious of the solidity of the material.
Ensuring the Design and Installation Accurately Met Designers’ Standards
The vein-matched pattern for all elements were made possible using Euromarble’s new patent-pending virtual dry-laid system. According to Canali, each slab was scanned and digital dry-lay imagery was produced to match each cut slab background and marble vein to give a continuous appearance. A scale model of the digital dry-lay composition was also produced to check the configuration of the veins.
The final procedure was completing a true-size physical dry-lay in Carrara, where each stone was individually inspected for quality and finish, enabling the entire team to inspect and ensure the design accuracy prior to the installation in London.
“Each piece was unique,” Guest said. “Even though size-wise, there was a degree of repetition, aesthetically there is no repetition, so each piece could only go in one place. Thicker pieces were also needed for the substantial number carvings “100” and they were so big that they spanned over multiple pieces, so aligning the tile perimeters and the carvings inside was a challenge.”
An anchoring system was utilized for the entire installation. “The wall panels were fixed with external cladding, with a cavity about 95 mm, mechanically fixed and restrained with stainless steel brackets,” Guest said. “All stones were individually fixed back to the concrete structure, with the exception of the east wall. The walls were so long and the substructure movement such that we had to cope with differential movements and long-term creep—as it is a 50+ story building, the bottom of the core does creep quite a bit with all that weight going down it.” While movement in building can be caused by many things, including moisture changes, vibration, and differential settlement, “creep” refers to movement that occurs as a result of time-dependent loads.
“The core, which normally is concrete, was a mix of concrete and secondary steel on one end,” Guest added. “We designed and installed the secondary steel; this of course behaved differently because the steel did not have the 50+ stories bearing down on it, so no long-term creep happened in that part.”
Despite the variety of intricate processes required for the design and installation of 100 Bishopsgate, the project was successfully completed in 2019 and has received various accolades. The project received a 2019 Natural Stone Institute Pinnacle Award in the Commercial Interior category.
“The architects valued the expertise the stone importers brought to the project and their dedicated team who helped realize the concept through their careful composition of the digital dry-lay process to match the marble background and veins,” Arney said. “It is for all these reasons that 100 Bishopsgate is a significant project to the architects on the team.”