working details: An aluminium roof with projecting gutter
Each three-storey teaching block is X-shaped in plan, with a render finish to the gable walls and to the walls that face adjacent buildings.The pitched roof is covered with standing-seam aluminium sheet; it oversails the gable walls, 'wraps down' to act as cladding to the walls that face each other, and extends over the rendered walls in the form of an aluminium gutter set above a strip of attic glazing.
The structure consists of a series of cylindrical 350m-diameter concrete columns at 6m centres, which run inside the walls.They support 12m-span floors of precast planks with structural topping and a steel roof structure of 457 x 152mm universal beams with tapered ends and 152 x 89mm purlins.Columns and beams are exposed and the profiled metal roof deck liner tray acts as the ceiling soffit.
The rendered external walls comprise a double leaf of blockwork with the cavity partly filled with insulation: the inner leaf rests on the floor slab; the outer leaf is load-bearing and is restrained at each floor level.
The sand/cement render has a painted finish.
Above the attic glazing, the roof deck terminates in a proprietary Kalzip fascia. The structural zone below is clad with an insulated polyester powdercoated aluminium fascia supported by a 150 x 90mm angle bolted to the perimeter purlin.
The 760mm-deep gutter is formed of mill-finished aluminium sheet supported by tapered galvanised steel gutter brackets at 6 metre centres; they are bolted back with thermal breaks to a framework of steel angles, which supports the internal wall liner. At the leading edge the gutter is braced with a 168mm diameter CHS. Rainwater is discharged into 100mmdiameter aluminium RWPs.