An extra storey to provide computer and technology classrooms has been added to the single-storey concrete-frame building with brick masonry walls. The structure of the additional storey is a timber frame, clad with cedar and roofed with Kalzip aluminium sheet, a light-weight construction to avoid adding load to the foundations of the original.
A series of glulam columns run at the perimeter of the new original concrete ring beam, and an additional row of columns bisects the building at its centre, rising to divide the roof into a lower flat section and a higher curved section. This creates a clerestory which lights the central staircase space and allows cross-ventilation. Roof-supporting glulam beams are bolted to the columns with steel T-section plates.
The roof is clad with standing-seam aluminium sheet. The roof and the half-round aluminium gutters on tapered steel brackets create a robust aesthetic which requires little maintenance.
The walls are of treated timber studs infilled with insulation; the glulam columns are set within the walls so that the external skin - ply, battens and boarding - wraps around them, with an under-eaves trim of plywood onto which the gutter brackets are fixed. The external-finish, horizontal red-cedar boarding with feathered joints is laid in a series of three 150mm strips separated by a 50mm strip. This sequence provides a horizontal grid into which the varying sizes of window sills and heads can be inserted. The grid also accommodates the bay window to the staff room, framed and clad with timber, and has a standing-seam aluminium roof to match the roof above it.