Specialist stone contractors Szerelmey, based in London, carried out the dramatic Jura limestone, travertine and Cumbrian slate cladding and flooring contracts on two new buildings at Regents Place, a 13-acre, mixed use estate in central London, where fins on the wall create movement as shadows track the hours of the day. Szerelmey were appointed by the client, British Land. M3 Consulting were project managers, Terry Farrell & Partners were the architects and BovisLendLease the construction managers.

This development consists of two buildings, 10 and 20 Triton Street, formerly known as Regents Place, where London-based stone specialists Szerelmey have installed a strikingly curved Jura limestone wall with projecting Jura fins radiating out from it in the ground floor reception and lift lobby area of the building.

The fins were originally specified in a man-made compound of resin-bonded crushed marble, but the backing wall is Jura ashlar fixed back to a steel frame and clearly having the fins in the same material was preferable. But there were concerns about being able to achieve the desired result in natural stone until Szerelmey had convinced the team otherwise – and saved them money in the process.

The two-storey, concave reception wall curves away from the reception as it runs into the lift lobby, where the projecting fins gradually diminish to become rebates within the Jura cladding, all supplied by the German Solnhofen Stone Group. The wall comprises 350m2 of Jura and there are 1,600 linear metres of it in about 2,000 fins.

The projecting fins are honed to varying grades and grouped appropriately to create subtle changes of colour, light and shade as the natural light levels alter with the passing hours of the day. This gives the impression of movement across the surface, an effect enhanced by the naturally occurring variations in the limestone as well as the subtle differences in the finish of the stones.

Darren Moore of Szerelmey told NSS: “The original concept was always to use natural stone but the architect was resigned to using a man-made material. However, during the tendering process we were able to offer solutions and calculations supporting the use of Jura limestone, including mock-ups of how different finishes to the stone could achieve the architectural vision.”

Chris Wade, of Terry Farrell & Partners says: “The technical solutions proffered were key to realising the feeling of movement while being discrete as to not detract from the simplicity of grand gesture.”

Once the use of Jura limestone had been decided on Szerelmey were responsible for the detailed design and fixing. Fabrication involved the precise setting out and pre-drilling of the stone fins to enable them to house bespoke design cranked threaded dowel pins to hold them in place through the stone cladding.

Darren Moore explains: “The stone cladding is fixed on to its own secondary steel structure, which was also part of our contract work. It spans the whole two-storey height between the primary structure and is carefully designed and installed to maintain structural movement criteria. Once the stone cladding was fixed, the fins were dry hung to ensure aesthetic and alignment considerations before they were permanently installed.

“In essence it was fiddly but essentially simple, at the end of the day.”

The two-storey wall incorporates a stone fin mullion viewing window on the first floor lift lobby that overlooks the reception. Here the fins are deepened and reinforced by stainless steel that backs the mullions to span the opening.

Szerelmey also laid a 1,100m2 Roman travertine floor that perfectly complements the Jura limestone wall.

The floor is installed throughout the upper lift lobbies and in the lift cars and is also on the ground floor, where it incorporates under-floor heating.

At 20 Triton Street – formerly known as Regents Place Two – Szerelmey again undertook stone cladding and flooring work on both the ground floor reception and atrium, and in the scenic lift lobbies on the upper stories.

On the ground floor, the double height reception wall is clad in bands of Roman travertine. It is installed in differing course heights separated by stainless steel channels.

Darren says: “Within each band of travertine we have used various combinations of polished and brushed finishes to give a carefully designed and blended randomness of both texture and light. The effect continues within the travertine as it curves around into the ground and open fronted, visible, first floor lift lobbies. This is repeated on all the upper lift lobbies where the opposite walls are glass clad overlooking the central atrium.”

Chris Wade adds: “The quality of workmanship and material selection within 20 Triton Street allowed layers of detailing to be built up seamlessly, culminating in an outstanding piece of pattern making which is extremely tactile and befitting the grand entrance.”

“Honed finish Roman travertine is also used on the flooring throughout. As with 10 Triton Street, underfloor heating is incorporated in the ground floor. In total, 2,000m2 of Roman travertine was used on the flooring of the building and 700m2 was used on the cladding.”

The opposite wall to the ground floor reception curves around into the atrium. It is a double height wall clad in 300m2 of Burlington’s Blue-Grey English slate from Kirkby-in-Furness, Cumbria. It has been used in bands of differing height, separated by stainless steel feature channels.

Again, the slate has a variety of honed finishes to provide contrast within the wall.

The reception and atrium stone cladding is fixed back to bespoke secondary steel structures that were specially designed and installed by Szerelmey to incorporate the structural movement specifications of the primary structure.

Darren Moore says: “Only after visits to Italy and Cumbria to view various finishes on the stones could combinations of contrasting finishes within the wall cladding area be finalised.

“The curved sections of both walls were originally specified to use faceted stone. However, our early design input demonstrated that the required layouts and effects could not be achieved without compromise.

“Mock-ups of the curved material were manufactured and the client’s agreement was obtained to use material that is worked to the true curve. The benefit of that decision is now evident for all to see in the completed project’s stunning ground floor.”

Chris Wade said: “We have worked successfully on many prestigious projects with Szerelmey over the past 10-15 years, including The Point at Paddington, Swiss Cottage and the Home Office development. During this period they have become a much relied upon partner in delivering the quality and detail of our concepts both externally and internally."

Photographs: Tom St Aubyn