The UK's first prototype building to be made from cardboard, an after school club for Westborough Primary School, Westcliff on Sea, near Southend, Essex, was officially opened in November last year.

A team led by Engineers Buro Happold, completed the construction of a multipurpose cardboard building for Westborough Primary School, using cardboard components wherever possible. The project, the result of intensive research into the properties of cardboard as a viable construction material, was jointly funded by the research partners and the DTI through the Partners in Innovation scheme.

The Westborough School building comprises an after school club, a kitchenette, a storeroom and a toilet block. Following prototype development, the project went onsite summer 2000, and is now ready for use. The project team aimed to achieve a building using 90% recycled materials, and for the building to be 90% recyclable at the end of its life.

The research project team includes Buro Happold as engineers, working to designs from architects Cottrell & Vermeulen Architecture. Three manufacturing companies, Paper Marc, Essex Tube Windings and Quinton and Kaines developed, tested and manufactured cardboard materials, tubes and panels used to construct the building. Franklin Building were the main contractors who put the building together. Additional funding support came from the Cory Environmental Trust in Southend-on-Sea.

The design allows exposed cardboard where practical, and reflects the nature of cardboard, with 'corrugations' on the south wall. Although it might have been simpler to produce a basic 'box' building, the team felt that this would not show the greater capabilities of the material and the manufacturing processes available for it.

Cardboard is made almost entirely from recycled material. It is possible to make cardboard products with sufficient compressive strength to carry structural loads, thereby displacing the use of other more material and energy intensive products such as concrete or steel. The project shows the possibilities and assesses the benefits of the innovative use of cardboard within buildings, bringing long-term benefits to the country through reduced energy consumption and material wastage.

The biggest challenge in designing with cardboard was overcoming the twin threats from fire and water. Cardboard is surprisingly good in fire, behaving in a similar manner to solid timber, charring on the surface rather than burning quickly. A chemical treatment minimises the surface spread of flame, and further reduces risk.

The wall design incorporates a three level approach to keep moisture out. The paper in the card itself has a small amount of water resistance, through an additive that can be removed if the card is re-pulped. Secondly, there is a waterproof layer over the surface of the card that can be removed before the board is recycled. Finally, there is overcladding to the waterproof layer in vulnerable areas - all of the outside and on the inside up the walls.

Cardboard tubes help support the roof. Existing use in pile sleeves, void formers and providing formwork for concrete columns show that the tubes have enough strength to do this, and they give a striking visual effect.

A timber truss supports the centre of the roof because the span was too large for the panels that could be made. Although not ideal when aiming for an all-cardboard building, it is a pragmatic solution to working with the material. What is most important is the success of the project, delivering a useful building for the school.

For more information contact Bentley Systems South Africa, 011 462 5811.