From Permaculture Magazine no. 37

It probably won't come as much of a surprise to readers that as a nation we generate, on average, three times our own body weight in waste every 3 months (figures, FOE). A significant amount of this is comprised of paper and cardboard. Although itself made of low grade recycled paper fibre, cardboard can be difficult to reuse and many local councils at the present time exclude it from waste collection schemes. Now there are only so many permaculturists out there creating sheet mulch beds, so what happens to the rest?

Supported by the Department of the Environment, Transport and the Regions (DETR), structural engineers Buro Happold have been addressing this issue by looking at the potential for using cardboard as a viable building material. Research director Dr. Andrew Cripps explains how a widespread problem can be turned into an abundant resource; "People think of cardboard as a disposable, short life packaging material with poor properties. In reality it can perform very well over an extended period if it is designed correctly and treated properly. It is also made from a waste product for which there are few alternative uses - paper. There are already several common uses of cardboard in construction: doors are filled with a cardboard honey-comb; tubes are used for column forming and as pile sleeves; panels are widely used in temporary structures."

Previously Buro Happold's work in this area has included the Japanese Pavilion at the 2000 Hanover Expo and the 'Shared Ground' Zone in the Greenwich Millennium Dome. However, Dr Cripps wanted to go a step further by building a permanent cardboard building that would be a long lasting functional structure rather than simply an impressive exhibition showcase.

Richard Cottrell and Brian Vermeulen, an architectural partnership known for their imaginative school design work, were asked to become involved. They proposed the construction of an after-school club at Westborough School as a prototype project. This primary school, the largest in Essex, is situated in Westcliff On Sea, a heavily built up inner urban area locked between two main trunk routes to London. The school playgrounds are wall to wall tarmac used daily by up to 800 pupils and pre-school children aged between three and eleven. In recent decades LEA cutbacks have seen the environment become ever more 'caretaker friendly', with ease of maintenance being the only priority as the grounds’ few trees were removed and grass areas were turned into a car park. In addition, there are few safe leisure facilities for young children in the surrounding area. Gardens are small and often shared between multi-occupied houses, and although a new sports complex has recently opened in the area, this is aimed towards older teenagers. Therefore the school plays an important role in the provision of after school and holiday activities, particularly for working families.

Making best use of the site for the benefit of both pupils and the community has meant moving towards more of a 'peoplecare' approach, and head teacher Jenny Davis and her staff have been determined to return Westborough to being once again a 'child friendly' landscape. Working with Cottrell and Vermeulen, who believe that "just because money is limited, imagination doesn't have to be", the school has since 1992 been developing an innovative range of building and playground projects. This has included re-greening it’s environment with tree planting schemes, garden construction and raised bed building, as well as participating in events such as the Hampton Court flower show.

Following consultation with the school, the agreed aim of the project was to build a structure comprising of a clubroom, kitchenette, store room and toilet block using 90% recycled materials, and for the building to be 90% recyclable at the end of it’s projected 20 year lifespan. Such an integration of ‘earthcare’ values to urban education means that the cardboard after school club building project is instrumental in developing two key areas of DETR construction policy. One is the move to more sustainable construction methods, whilst the other is the integration of the supply team. This project would not have worked without the whole team, from the architects, fabricators, builders and clients, all co-operating to play their own part. As it grew, so too the design evolved in a holistic way to use the expertise of all of the team.

Having secured funding from the DETR’s Partners In Innovation scheme and the Cory Environmental Trust, the vision started to become reality. Early in 2000 large recycling bins appeared in the school playground into which the children and their families were encouraged to deposit their household cardboard waste. This was then taken away and converted into the main building components. Principally these consist of the wall panels and tubular support pillars:

• The 1.5 m by 2 m panels consist of a series of layers. The outside surface of each panel is a 6 mm thick piece of solid cardboard. Enclosed between these two stiff pieces, are 3 layers of 50 mm honeycomb shaped cardboard, each layer separated by a 2 mm layer of solid card. On the side of the panel, which will be inside the after school club, there is an embedded layer which is poly-coated layer to provide a vapour barrier. The panels are edged with 50mm timber frames.
  
  
• The cardboard tubes are between 2 and 2.5 metres long, with a diameter of either 180 or 230mm. The edges to the tubes are 15 mm thick solid card. These tubes are thus very strong, and when stood side by side and used a 'wall of tubes', they can easily carry the load, or weight, of the roof truss.

The building design is intended to reflect the nature of cardboard and zig zag 'corrugations' on the south wall add to the load bearing capacity of the support pillars. A timber truss supports the centre of the roof. Although a compromise in terms of aiming for an all-cardboard building, Dr. Cripps felt this was a pragmatic solution for ensuring the success of the project and delivering a useful building for the school within a reasonable timescale, although he states that a cardboard beam would have been technically possible.

Ensuring resistance to fire and water have been the biggest design challenges. In the case of the former, Dr. Cripps found that cardboard behaves in a similar manner to solid timber, charring on the surface rather than burning quickly. The panels and tubes were also treated to minimise the surface spread of flame. Wet cardboard will lose strength very quickly, thus the wall design incorporates a three level approach to keep moisture out. A plastic coated material outer layer, featuring an inner breathing membrane, protects an inner load-bearing core. The main panel is as water-resistant as possible, using techniques researched from the packaging industry. A third level gives the paper in the card itself a small amount of water resistance, through an additive that can be removed if the card is re-pulped.

The ability of the cardboard classroom to withstand fire, water and physical damage was dramatically put to the test by the BBC’s ‘Tomorrow’s World’ program in March 2001. In a live broadcast the panels and tubes were subjected to flame-throwers, a drenching from fire brigade hoses, the weight of a one tonne van, and a sledgehammer attack from Glenn Ross, the world’s strongest man. Apart from superficial damage, the materials passed with flying colours, although I’m not so sure the same can be said about Mrs. Davies’ normally unfazed composure...

The project's commitment to sustainability does not end with it's outer structure. The floor is made of recycled rubber tyres, whilst cupboards and fittings are made of Tectan, a material produced from used drinks cartons.

Heating and hot water for the after school club is delivered through a Vaillant ecoMAX 600 condensing system boiler and VANTAGE unvented hot water cylinder. By ensuring optimum performance and efficiency, the system obtains the highest SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK) band 'A' rating, with seasonal efficiencies in excess of 90%. This high efficiency and consequent reduction in gas consumption results in a reduction in CO2 emissions of around 15% to 20%, a favourable comparison against even modern non-condensing boilers. In addition, the low NOx burners achieve an emissions level of less than 70mg/kW hour. As Dr Cripps explains; "We chose the Vaillant ecoMAX condensing boiler because not only does it deliver the kind of heat that we need, but also fits in with the environmental ambitions of the project."

In 2002 the vision of the school’s staff and governors combined with the tenacity of the architects and engineers paid off when the cardboard classroom became the first project ever to win two RIBA (Royal Institute of British Architects) special awards. These were the Stephen Lawrence Prize, named in memory of the murdered black teenager who planned to become an architect, and The RIBA Journal Sustainability Award.

The awarding judges commented, "We were completely won over by The Cardboard Building for Westborough Primary School. It is Europe’s first permanent cardboard structure, providing a much needed educational and community space as well as an inspiring structure... It also acts as a continuous learning experience for children both in terms of the strength and economy of folded structures and the recyclable and sustainable issues that the building demonstrates. A brave attempt on a shoestring budget: the embodiment of the truth that 'necessity is the mother of invention'."

So the experts like it. But what about the children? For one young pupil the whole idea is nothing more than common sense- "If you can make an igloo out of snow, why can’t we make a classroom out of cardboard?"

Graham Burnett, Jan 2003, with special thanks to Dr Andrew Cripps for assistance and technical advice.

All photos by Dr Andrew Cripps & Cottrell and Vermeulen

For more information about the cardboard classroom visit,

http://www.cardboardschool.co.uk