Folding planes: The potential of cardboard as a green and economical building material finds ingenious expression in this after-school activities club.

The notion of using cardboard as a building material might seem ridiculously improbable, but it has been making regular appearances in temporary structures by architects such as Shigeru Ban, who developed a series of refugee shelters in Japan, Rwanda and Turkey using cardboard tubes. Working with engineers Buro Happold, Ban also designed a dramatic tubular cardboard gridshell structure for the Japanese Pavilion at Hanover Expo (AR September 2000). Buro Happold's research and expertise in cardboard technology led them to become involved with a more recent project which lays claim to be Europe's first permanent cardboard building. Designed by the young London-based practice of Cottrell & Vermeulen, this after-school club in Westcliffe-on-Sea incorporates cardboard components to both support and clad the building. Westborough primary school is the largest in Essex and its 750 pupils were eager and active participants in the project, collecting the waste paper that formed the basic raw material for the building's cardboard panels and tubes.

Despite lacking obvious structural, waterproofing and fire resistance properties, cardboard is essentially a very green material (being easily recyclable as well as being made from recycled matter such as paper waste). It is also very economical. Although the composite cardboard panels used here ultimately cost around the same as a brick and block structure ([pounds sterling]30-[pounds sterling]40 per sq m), speed of erection is much quicker -- a mere week from slab to watertight structure.

Cottrell & Vermeulen's building is designed to last 20 years and to be 90 per cent recyclable. A simple single-storey pavilion is enclosed by folded concertina walls and roof, prompting irresistible comparisons with origami. (Instructive origami diagrams by artist Simon Patterson playfully embellish the walls.) The large main club room, which can be used for a variety of activities by both schoolchildren and the local community, is adjoined by a store, kitchen and WCs.

Cardboard is used for both structure and cladding. At either end of the building, two lines of 11 cardboard tubes, 183mm in diameter, support a timber roof truss. Arranging tubes in lines or clusters helps to distribute applied loads and prevent the material's tendency to creep, or deform over time. Single tubes also support lintels above window openings. A layer of varnish protects the cardboard from sticky hands and a squiggle motif provides a simple means of graphic ornament.

Cladding panels are formed from a cardboard honeycomb edged with timber strips. The timber frame improves structural performance and also means that the panels can be fixed using conventional joinery techniques. An external layer of fibre cement board and an internal layer of pin boards made from recycled newspaper provide fire resistance. Panels also contain a vapour barrier layer and the cardboard pulp was chemically treated to counteract its hydroscopic (sponge-like) properties. Buro Happold estimate that the material's insulative properties, even without the composite layers, should exceed statutory requirements by 25 per cent.

As a prototypical application of cardboard technology, this ingenious little building shows that a commonplace material has tantalizing potential for an economical and environmentally responsive architecture that need not literally cost the earth. Further developments are keenly awaited.