A sculptural exploration of cross laminated hardwood
Status: Completed 2013
Not a stair without end, but a stair designed to be endlessly reconfigured: an entirely prefabricated construction, each piece an essential part of the expandable structure. It also gave rise to an entirely new, sustainable timber product: cross-laminated hardwood.
CollaboratorsSponsor American Hardwood Export Council
Structural Engineer Arup
Material and Fire Specialists Arup
CLT Production Imola Legno
Lighting Designer Seam
The London Design Festival (LDF) is a world-renowned event celebrating and promoting London as the design capital of the world. In 2013, the organisers approached us to design a landmark project to allow people to see London in new and surprising ways.
The project was built in wood, to underline the merits of the material as a sustainable form of construction. It also allowed the project’s sponsor, the American Hardwood Export Council, to showcase their products. The installation was positioned outside the Tate Modern gallery, one of London’s most visited and best-loved art galleries, for four weeks.
We wanted to create an installation that would inspire the general public with the playful possibilities of architecture and push the unique properties of cross-laminated timber.
Inspired by M.C. Escher’s popular drawings, Endless Stair is not a stair without end, but a stair designed to be endlessly reconfigured: a three-dimensional exercise in modular composition, structure and scale. An entirely prefabricated construction, each piece is an essential part of the additive structure. Loads are transferred through demountable flights that can be entirely recycled on another site in a different configuration.
Through collaboration with the sponsors, Endless Stair gave rise to a new material.
The tulip tree is a light and strong species of the magnolia family. It is a plentiful and sustainable American hardwood export, but for the first time Endless Stair uses it as a cross-laminated timber (CLT). With an extraordinary strength-to-weight ratio, the design exploits the performative and aesthetic properties of a beautiful species.
In total, 11.4 tonnes of tulipwood was used in its production, absorbing 20 tonnes of carbon in its 187 steps. But Endless Stair is a fast and dry construction, easily demountable, and entirely recycled on another site.
This was demonstrated with a further, column-free composition, using seven of the original thirteen flights at the FuoriSalone 2014 exhibition in Milan.
Endless Stair was a huge success for the festival, its sponsors and the many thousands of people who climbed its steps. We are proud of its impact on the cultural life of the Capital and what it says about our commitment to innovation and sustainability in building design. We hope that, as it is reconfigured for other design festivals, it can present a fresh case study for engineered timber becoming the key construction material of the 21st century.
Designing the system for the Tate Modern installation took a month. The second time around it took us a day.