When architects from Dawoffice saw the overcrowding at Thionck Essyl’s only secondary school, they resolved to build a new one through their charitable foundation, Foundawtion. Climatic comfort and low cost were paramount. Clay, the region’s most abundant material, was freely available on site; the quarry became the school’s sports field. The catenary vault form was chosen because it works purely in compression – the only stress that clay can withstand. Clay vault modules produced by volunteers using local techniques are enclosed with wooden lattices, allowing light in. The clay and lattices act as an evaporating cooler – no artificial air-conditioning is required. Grooved metal sheeting protects the clay from rain and sunlight. The detached modules or "awlas" are arranged in year-group classroom sets around a series of squares, each accommodating a pre-existing tree. A library, two administration volumes, sanitary facilities and a Foundawtion space complete the complex. Its modular form facilitates future expansion.