Stairway to heaven
A commission for a city centre staircase may not be regarded as the most glamorous of jobs. But for artist Thomas Heatherwick design is what you make it. Admittedly the staircase in question is intended to form a visual link with the Blue Carpet arena in Newcastle upon Tyne (AJ 8.2.01). However, it must be said that the scheme is not in what you might call a salubrious area of the city. So what is it all about?
Having commissioned the upgrade of the pedestrian area outside the Laing Art Gallery, Newcastle upon Tyne City council took some convincing of the need to rejuvenate more than the dead space directly outside the gallery entrance. For Heatherwick's office, the whole route across John Dobson Street to the east and a considerable distance to the west - a regular path for shoppers and park-and-riders - needed attention.
Eventually the council agreed to a limited extension of the brief; to replace a prominent and rather threatening metal municipal staircase with a new one more in keeping with the overall upgrade. The argument that the staircase and the Blue Carpet be linked was unfortunately lost, and notwithstanding the fact that people will be drawn to use the stair - in the same way that the Newcastle quayside promenaders have increased because of the Millennium Bridge - it would have been sensible to have made access and egress an equally enjoyable experience.
However, the fact that the works happened at all is a result of resolute client/designer appraisal and lobbying. Originally, the work for the Blue Carpet and staircase was allocated a total of £300,000. In what Heatherwick acknowledges was 'a very long process indeed', the message got through to the council that 'it would not get anything original for that sort of money'. Once the need for more cash was admitted, Lottery applications, European funding requests and other accounting procedures were submitted for approval. The budget crept up to £800,000 and then to its final figure of £1.2 million. In the process Heatherwick has spent 370 days on the scheme including making 75 trips to Newcastle.
The staircase's design is unique and its manufacture a triumph. Comprising a central, helical core beam which twists, rather than spirals, down to ground level, it is designed to spill pedestrians out into the direction of the town centre instead of the previous dog-leg design which ejected people in towards the blank face of the existing brick wall.
The spine is made up of 840 individual sheets of 18mm Canadian Douglas Fir plywood, cut to approximate shape, with a maximum 6mm oversize allowance (see diagram).
Each plywood board was then pinned and epoxy-resin bonded, layer by layer, to build up a spine support beam 2.2m high and 500mm wide, each layer having to set before the next was laid. This rough composite was then planed and spoke-shaved on the inside and outside edges to produce a pristine finish - a work of art in itself.
A team of four, skilled boat-building craftsmen carried out the work over a period of seven months.
The plywood beam has been designed and executed as a self-supporting structural member, save for a single discreet support pole at the lower edge which has been introduced to keep the dimensions to manageable proportions. Even so, Heatherwick says that its labour-intensive manufacture was a 'thankless task'. Built against the scaffolding without formwork, it was only when about the 50th layer went on that the contractors could see the beauty of their creation.
'Only then did the boatbuilders seem pleased with themselves', says Heatherwick, allowing himself the comment that he too was 'thrilled', adding, 'it looks better than I thought'.
This huge plywood 'ribbon' is capped off, top and bottom, with a flush cedar wood capping and the whole structure given six coats of yacht varnish. The bottom of the spine, which sets into the ground is coated with tar - flush with the finished floor. This ground landing will be of 'unremarkable paving slabs' to differentiate the old and the new, and to 'leave a sense of expectancy' in the area between the staircase and the Blue Carpet. Heatherwick can undoubtedly sell the problems caused by lack of budget as an opportunity of design intent.
The spine has been predrilled to take the prefabricated stair segments, comprising seven or eight risers and landing. These will cantilever out from the spine for a width of 1,900mm, to take the external balustrading, made up of basic sandblasted stainless steel balusters and capping rail. Careful drilling was essential to avoid thousands of woodscrews within the spine (which added to the structural integrity of the unit), and to ensure a match with the stair geometry. The external handrail will match the inside handrail of built up plywood manufactured in the same way as the spine.
Heatherwick acknowledges that he wants passers-by to gaze and puzzle over how the structure was built, a mystery encouraged by the swathe of tarpaulins covering the stair during its laborious construction.