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Crowning glory

Hoardings come down later this year on the final stage in the restructuring of Kings Cross station, creating a new open space for Londoners. Adrian Greeman reports.

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London’s King’s Cross station was somewhat overshadowed by the renovation and extension of its next door neighbour St Pancras for the High Speed 1 rail link terminus. The station’s famous Gothic Victorian hotel, high clock tower and huge glazed arched station sit alongside King’s Cross and have stolen much of the attention.

But since 2007, a massive £550M project has been underway to make sure King’s Cross is no longer overshadowed by its showy neighbour. Last year saw the opening of the spectacular western concourse to much acclaim, and in a few months the full impact of the upgrade will be revealed whenthe hoardings come down at the front to reveal a clear view of its arched façade and clock tower, both listed structures and fine pieces of Victorian architecture.

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Kings Cross Square: How the original Victorian station front looked

The open space in front of the station entrance will also be a revelation, a new granite piazza covering7,000m2, with seats, trees and kiosks, opening up this previously cluttered junction of Euston Road and York Way along the station side.

The reworking will give Londoners their first view of how the station was meant to look when it was originally designed in the 1840s by Lewis Cubitt.

The large yellow brick double arched frontage has been almost continuously obscured ever since; its lower entrances nothing more than the “brick bit at the back” which passengers passed through to reach the platforms.

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The reworking will give Londoners their first view of how the station was meant to look when it was originally designed in the 1840s by Lewis Cubitt

The station front concourse, added in the 1970s as a low flat roofed extension built out to the busymain road, is what most users thought of as “King’s Cross”. It was the space where they bought their tickets, had a coffee, checked the train times or accessed the Tube and taxi rank.

The whole of this enclosed space can now go, following a £550M upgrade of the main station. This work has seen the station get a newly restored, clear glazed roof. There are also renovated multi-storey brick offices each side, east and west, running along the full length of the platforms and a new platform “0”. And, most significantly, a completely new and much more spacious concourse in a dramatic curving glazed space of its own on the station’s western side.

Similar to, but bigger than the nearby glass-roofed British Museum concourse, it is the largest single span glass enclosure in Europe. Impressive in itself, it in turn sits above a new underground northern ticket hall for the Tube.

 

Once all that opened last April, work could start on the final phase of construction at the front, demolishing the 1970s structure and replacing it with a landscaped city square.

Designed by architect Stanton Williams - which won a competition for the concept - and structural engineer Arup, this will be a granite paved area with a strong contrasting black and white finish, trees and shrubs in 2m high raised stone clad planters and black granite seating. York paving will finish the perimeter.

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Progressing well: King’s Cross Square worksite

A key design feature is a series of wide black stripes set into the white granite background that “echo the platforms inside” according to client Network Rail programme manager Matt Tolan.

An important element of the design will be night lighting, with sustainable LED floodlighting from three high poles, uplights for the façade and downlights in the stone benches.

“There will also be kiosks and retail space,” says Tolan. These are useful but also help deal with a number of difficulties, particularly three large rounded enclosures that house ventilation stacks for the Tube lines beneath. Two are circular and one egg-shaped in plan - unsurprisingly known as “the egg” - and they are all the size of small buildings.

They are incorporated into the design using a black granite cladding, which is smooth below and ribbed above, and they will also have retail space extensions around them.

Another major difficulty for the design and later construction is that the original King’s Cross London Underground ticket hall, now one of three interlinked spaces, sits just below ground at this point.

“There is a roof slab of just 300mm thickness underneath most of the area,” says Patrick Shaw, project manager for contractor Murphy, which has been carrying out the £12M contract to build the new public square.

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Coming down: An excavator removes the 1970s space frame roof

Fortunately, he says, because the ticket hall was rebuilt after the Tube fire in 1987, this is a modern structure and sufficient for the loads going on top of it. He should know as he worked on that job too.

The job has some significant challenges for the construction work itself.

The first issue is that it proceeds in the middle of a live station space, one of the busiest in the capital with a throughput of 47M passengers a year. Most of the arrivals still come through the front of the station, and out past the site.

“That has meant taking a fairly conservative approach to the removal of the old structure,” says Shaw.

This is the second difficulty: the ceiling, or roof, of the structure is a space frame which was very modern for its time in the 1970s but with the complication that its components all interact to span the space both longitudinally and laterally. “Remove one part of it and the whole thing loses stability,” says Shaw.

“Remove one part of it and the whole thing loses stability”

Patrick Shaw, Murphy

Murphy hired in specialist subcontractor AR Demolition of Leicester, which had previous experience with the frames, and together they devised a complex sequence of props and tie downs to keep the frame in place as parts were cut away.

The largest chunk came out on Christmas Day, one of the few occasions when it was possible to get possession of part of the busy Euston Road.

Handling and assembling the granite is another complex issue. Firstly, two colours of stone are sourced completely differently; the white granite slab pieces are cut and shaped in Portugal and the black in China. The shaping has to be accurately done for a fine finish.

But even greater accuracy is required for the cladding on the vent structures. This is smooth but curved at the base and then has a close spaced vertical rib effect higher up. “Each piece is uniquely shaped and fitted,” says Shaw. The supplier has devised a complex numbering system for the placing and installation of the pieces.

The tree planting is also an issue. With just 300m down to the ceiling of the Tube below there cannot be tree roots growing everywhere.

Trees are in concrete planter boxes, therefore, which confine the root system; they then have both drip irrigation and aeration systems to maintain growing conditions.

For the historic façade itself there is to be a protruding canopy, which will be similar to the original design of the covered space where Victorian gentlemen could be dropped off in their carriages.

Finally, around the outside will be a rank of black security bollards, anchored strongly enough to prevent a vehicle being driven through.

The whole space will be an inviting entrance way to the double station complex, the multiple Tube lines beneath and also to the huge redevelopments on Network Rail land to the north of the station and along York Way, a vast complex of new offices and other buildings.

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