A lightweight glulam structure has allowed Eger Architects to extend upwards an old button factory in Camberwell, south London, so that it can perch a second floor of living space on top of its new offices. Circular glulam columns rise from the position of the steel columns below, which support the curved glulam beams. This helps avoid the need for any strengthening to the original structure or improvements to the foundations. The glulam columns are hollow, made up of long wedges of timber with a circular hole in the centre, a format that is lighter and stronger than a solid column. With one boundary having a height restriction that meant the resulting floor-toceiling height would be too low to be habitable, the architect's solution was to curve the roof upward from that side. It moves out to overhang a roof terrace. The glulam beams were curved accordingly, with elegantly tapering ends.Eger Architects' John Eger described the manufacturer, Danish company Lilleheden, as 'very accommodating'.
A structural ply membrane sits directly on the cross beams, with insulation above. The columns, beams and ceiling are stained with a white pigmented organic treatment from O&S Paints. Walls to the flat are of timber frame with softwood studwork and structural-ply membranes. Externally the walls are protected by a rainscreen of profiled mineral-fibre cladding from Eternit. By using a timber-framed structure, the architect has been able to create a change of mood in its upward extension.