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London Design Festival
Endless Stair

14 Sep 2013 to 22 Sep 2013
Landmark Project
Monday – Sunday 9am-dusk
Free Event
The installation will be open 13 September - 10 October 2013
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Endless Stair sees the London Design Festival reviving its longstanding relationship with the American Hardwood Export Council (AHEC) in a playful, yet technically ambitious public project to be installed with the powerful backdrop of one of the city’s best-loved landmarks, Tate Modern.

Southwark / Blackfriars station

Installed outside Tate Modern, the towering structure will invite 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 provides 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 will be composed here 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 is made using softwood because it provides a cheap and readily available source of wood fibre. The Endless Stair pioneers the use of a hardwood species, which is inherently lighter and stronger than its softwood equivalents.  The CLT panels for Endless Stair are being 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”, states 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 is the most recent in a series of innovative projects that AHEC has commissioned for the 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 is using data from its recent Life Cycle Assessment (LCA) research project to produce a full ISO conformant environmental profile for the structure. It will be the first time this will be done for a major installation at the London Design Festival.

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

Endless Stair is located on the riverside of Tate Modern, Bankside, SE1 9TG

Opening Hours:

13 September - 10 October 2013

Monday – Sunday 9am-dusk

Endless Stair Facts
• American tulipwood (Liriodendron tulipifera) is one of the most abundant timbers in North America. It has excellent structural properties.
• There will be a total of 11.4 tonnes of tulipwood in the Endless Stair and none of it will be wasted. The project has been 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 is 436m – equivalent to 4.5 times the height of Big Ben.
• The Endless Stair has a total of 187 steps. The shortest route to the top is 48 steps.
• Arup estimates that a maximum of 93 people will be on the Endless Stair at any one time.
• The Endless Stair will be accessible during daylight hours. At night it will be lit with an artistic lighting scheme by Seam Design using luminaires provided by Lumenpulse.
• Endless Stair will have a full environmental profile; all the material, transport and manufacturing processes are being recorded and Sustainability Consultants, PE International, will produce a report to identify the life cycle impacts.

For more information visit

Supported by the American Hardwood Export Council

(Image credit) Visualisation of Endless Stair at Tate Modern, Image by Cityscape

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
Partner information

Over nine days in September, the London Design Festival featured hundreds of events which took place across London, showcasing the city's pivotal role in global design. The London Design Festival 2015 was held 19-27 September.

The centerpeices of the Festival are our commissions, the Landmark Projects created with the help of our generous supporters. For these Landmark Projects we commission some of the world's greatest architects and designers to create pieces of work in London's best-loved public spaces.