Endless Stair




Landmark Project

Endless Stair saw London Design Festival reviving its longstanding relationship with the American Hardwood Export Council (AHEC) in a playful, yet technically ambitious public project installed with the powerful backdrop of one of the city’s best-loved landmarks, Tate Modern.

Installed outside Tate Modern, the towering structure invited visitors to climb and explore a series of 15 Escher-like interlocking staircases made from a prefabricated construction using 44 cubic metres of American tulipwood donated by AHEC members. As a viewpoint, Endless Stair provided breath-taking views along the River Thames.

The complex construction is designed by Alex de Rijke, Co-Founder of dRMM Architects and Dean of Architecture at the Royal College of Art, working closely with engineers at Arup. De Rijke has described timber as ‘the new concrete’, predicting that it will be the dominant construction material of the 21st Century.

 “There is a ‘wood revolution’ going on in the construction sector and dRMM are one of the architects at the forefront so it is very fitting that their dramatic ‘Endless Stair’ design will significantly inform the debate, show hardwood in a new light and challenge traditional thinking within the construction industry.” David Venables, European Director, AHEC

 “The programme of modern art and architecture at Tate Modern, combined with the Thames panorama of London, provides a context to which dRMM's Escher inspired installation can make a distinctive contribution." Alex de Rijke, Co-Founder of dRMM Architects

Tulipwood is a plentiful and sustainable American hardwood export, and was composed for the first time as cross-laminated timber (CLT). CLT is a method of exploiting the structural properties of timber to create panels that can form buildings quickly, efficiently and sustainably. Traditionally, CLT was made using softwood because it provided a cheap and readily available source of wood fibre. The Endless Stair pioneered the use of a hardwood species, which is inherently lighter and stronger than its softwood equivalents.  The CLT panels for Endless Stair were produced by Imola Legno, a major timber distributor in Italy.

“Tulipwood is amazingly strong and stiff for its weight compared to many other species. Tulipwood CLT offers a really exciting addition to the CLT family”, stated Adrian Campbell, Associate Director, Structural and Lead Engineer from Arup. “This project provides fertile opportunity for this elegant sculpture to act as a test bed for the creative use of timber.”

This was part of a series of innovative projects that AHEC commissioned for London Design Festival including the Timber Wave, designed by AL_A, which stood outside the main entrance of the Victoria & Albert Museum in 2011, and the Sclera pavilion designed by David Adjaye in 2008.

For the Endless Stair project, AHEC used data from its recent Life Cycle Assessment (LCA) research project to produce a full ISO conformant environmental profile for the structure. It was the first time this will be done for a major installation at London Design Festival.

Endless Stair was open for the public to ascend during the day. The structure was closed overnight but illuminated for public viewing with a scheme designed by London-based design practice Seam Design using equipment by Lumenpulse. Endless Stair was fabricated and installed by a specialist team at Nussli.

Endless Stair Facts
• American tulipwood (Liriodendron tulipifera) is one of the most abundant timbers in North America. It has excellent structural properties.
• There was a total of 11.4 tonnes of tulipwood in the Endless Stair and none of it was wasted. The project was designed to be reconfigured and re-used.
• Cross-laminated timber is an increasingly popular construction material. It is normally made from softwood. This pioneering use of hardwood cross-laminated timber reduces the amount of material needed and the thickness of the elements.
• The total length of all the panels in the endless stairs was 436m – equivalent to 4.5 times the height of Big Ben.
• The Endless Stair had a total of 187 steps. The shortest route to the top was 48 steps.
• Arup estimated that a maximum of 93 people were on the Endless Stair at any one time.
• The Endless Stair was accessible during daylight hours. At night it was lit with an artistic lighting scheme by Seam Design using luminaires provided by Lumenpulse.
• Endless Stair had a full environmental profile; all the material, transport and manufacturing processes were recorded and Sustainability Consultants, PE International, produced a report to identify the life cycle impacts.

Supported by the American Hardwood Export Council
Designed by dRMM
Engineered by Arup
CLT produced by Imola Legno
Fabrication and assembly by Nussli
Lighting by SEAM Design

Tulipwood lumber kindly donated by AHEC Members:
Allegheny Wood
Blue Ridge Lumber
Northland Corporation
Northland Forest Products
Pike Lumber
Shenandoah Hardwood Lumber Co
Verde Wood International

London Design Festival

Over nine days in September, the London Design Festival feature hundreds of events taking place across London, showcasing the city's pivotal role in global design. The London Design Festival 2018 will be held 15-23 September, featuring over 400 Partners, Landmark Projects, and V&A Commissions.

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