A great glass elevator – Herbert Crescent Lift, Knightsbridge, London

An eight-storey glass lift in an opulent Knightsbridge residence has taken glass engineering and construction to ambitious new heights. Steve Menary investigates.

Charlie and the Great Glass Elevator is a renowned novel and the centre- piece of Roald Dahl’s fiction which has been brought to life in a new six-storey mansion in Knightsbridge, central London.

A glass lift is at the heart of the project extending eight storeys from the basement to a roof terrace that has created what’s thought to be a world-first in a residential property.

“We think that this project took glass engineering and construction to new heights, literally and figuratively, and it is likely to be the tallest self-supporting annealed glass structure in the world,” says Gennady Vasilchenko-Malishev from engineering consultants Malishev Engineers.

According to the Bath-based consultant, the first stacked load-bearing glass walls began to emerge in the 1990s, such as the Glass Cube Reading Room at the Arab Urban Development Institute in Riyadh, Saudi Arabia, which was designed by Dewhurst Macfarlane & Partners.

Malishev took on and developed the principle of vertically stacked load-bearing glass further at the Boltons Place residential development in London, which was completed in 2006 and included a 20-metre high structure.

For the Knightsbridge project, these principles would be extended even further.

“From the early design meetings the architects wanted a ‘wow’ effect from this central feature in the house which would combine minimal design and maximum transparency,” says Malishev.

For all members of the design and construction team, producing such a ground-breaking scheme was to prove a challenging task. The scheme features an array of consultants and contractors with experience in high-end residential projects, including Tim Flynn Architects producing the design, Malishev working on the glazing for the lift and Walter Lilly brought on board as main contractor.

The building originally comprised four bedsits, which were bought by the client so that the property could be reverted back to a single Toblerone-shaped residence but all this consolidation has proved a long process.

Work has only just been completed but first started in August 2011 with the recon- figuration of the internal space to create an area for the lift. This also necessitated a major excavation project. The construction team dug down more than 25 metres and installed secant piling walls as a four-storey house was extended to eight levels.

“We certainly pushed the boundaries,” says Steve Edwards, contracts manager for Walter Lilly. He goes on to explain: “It was quite a challenge to get a piling rig in to dig down to that depth and we required a structural rig to lift the piling rig in.”

The basement work alone took around 11 months to complete and the centrepiece glass lift was two years in construction.

Finding a specialist sub-contractor willing to take on the lift element was difficult due to the challenging work.

Malishev adds:

“Many sub-contractors were simply afraid of this contract and refused to tender altogether, regardless of the costs.”

Only two companies were willing to put in bids. Axis Elevators won out, with the glass supplied by UK Glass. Installation of the glass began in March 2015 and the panels were lifted up using hoists and an overhead gantry then down through the oculus of the openable roof light.

A hydraulic ram lift was used as a working platform to facilitate the process of installation. Despite very tight working space, no glass panels were damaged during the installation process.

The last panel of glass was installed on 29 March 2016 and the lift was finally commissioned in January 2017.

The glass structure comprises a curved laminated glass cylinder in diameter with a cantilevered steel staircase wrapped around the outside. The enclosure size of the lift has been restricted to 1.4 metres, which was dictated by a very tight floor plate arrangement.

There is also an external door and an internal lift door, which are both glass. Due to the circular structure, this was also a challenge. Edwards says:

“It’s about the tightest radius you can get. All the glass pivots so you can clean the glass.”

There are three sheets of curved glass for the exterior of the lift shaft on each floor.

“It’s a parallelogram, and the glass is tied in at intermediate levels,” explains Edwards.

The glass shaft of the lift is split at each floor level with a helical steel handrail, which acts as the splice joint between the top and bottom glass panels as well as providing lateral restraint.

The top of the lift shaft is capped by static and openable semi-static roof lights and on each landing-level for the lift.

Malishev explains:

“A series of high precision rollers and rails were used on inner and outer perimeter rings to support the sliding roof light. The roof light is comprised of a crescent shaped walk-on double glazed units, spanning one metre between the inner and outer perimeter ring support.”

The sliding floor unit moves using a spur pinion gear with planetary-type motor and supporting V-shaped wheels and the self- supporting glass cylinder sitting on top. Malishev adds:

“This makes this mechanism truly unique in this kind of application. We were responsible for specifying the system and worked closely with the system manufacturer to advise our steel and glass fabricator with best available options as well as tolerances required.”

The exterior of the lift features bronze cladding. This was produced by Paul Dennis Metal Works, which like the rest of the project team has experience working on high-end projects in central London, including new gates at Kensington Palace.

In Knightsbridge, every piece of cladding was hand-made but this package could not be commissioned until the structure of the lift was completed. Once the lift was complete, the bronze cladding was applied to clad the stainless-steel H section profile on the exterior of the lift.

The lift goes below the basement level as the ram has to be situated beneath the lowest floor and is surrounded by a 169- step spiral staircase. At the top floor, this staircase leads to a glass retractable roof, which opens out onto a roof terrace with views of Knightsbridge including the nearby Harrods department store.

The glazed lift is a centrepiece in a house distinguished by up-market decor. There are British stone floors which were installed by Stone Interiors in most parts of the residence. Swaledale, Angelsey, Eskett, Salterwath and Swaledale stone was used and sourced from Chelsea-based supplier Britannicus Stone.

In the dining room, the floor is a combination of Swaledale with an Anglesey stone border by Britannicus Stone, while the kitchen features an oblong of Swaledale stone framed by American black walnut, and the master bathroom features the exquisite and rare Ball Eye Blue stone, which has been hand carved by Stone Interiors.
There is also a working fireplace and raw silk wallpaper supplied by Tatiana Tafur, but glass is a recurring motif.

Peter Layton from Bermondsey-based specialist London Glassblowing also worked on the decor to produce a collection of glass vessels installed in the dining room on the ground floor.

“We have a Connaught Hotel Art Deco inspired bar and bathrooms with bevelled glass,” explains TFA’s Brian Wade, who sourced designed and installed all the soft furnishings.

The scheme also features hand-made glass chandeliers. On the first floor, a glass chandelier created by Baroncelli has been christened ‘Storm Cloud’.

German designer Eva Menz crafted another glass chandelier christened ‘Up in the Clouds’, which is made from hand- blown Polish glass leaves and conches. This glass element also features real leaves collected from nearby Hyde Park by the family. Before the leaves were added to the chandelier however, they were dipped in 14 carat gold.

While an overall value has not been disclosed, £1.9m has been spent on fixtures and fittings alone.

In September 2016, the project featured on the UK Channel 4 series Millionaires’ Mansions, which has now also aired in Australia and New Zealand.

For all this opulence, Brian Wade says that the house is not intended as a status symbol. In March 2017, the clients,

a family of five, finally move into the property. Mr Wade adds:

“The client lives in London and their children go to school locally, so the home will be lived in and enjoyed. Often the shame of these projects is that you do all this work and they are only lived in two or three months of the year, but that will not be the case here.”

While Knightsbridge has seen a proliferation of mansions created by digging out basements, none can surely match this with a glass elevator that really does help the project fly.

PROJECT DETAILS

Project: Private residence, Herbert Crescent, Knightsbridge, London
Client: Not disclosed
Value: Not disclosed
Architect: Tim Flynn Architects
Consulting engineers: Malishev Engineers
Structural engineer: Michael Barclay Partnership
Quantity surveyor: Deacon and Jones LLP
Main Contractor: Walter Lilly
Joinery: John Spencer Joinery and Halstock
Lift: Axis Elevators
Glass: UK Glass