The double curved geometry of this auditorium soffit posed formidable challenges to analyse and to achieve. The visible egg comprised 400 Birch plywood panels pressed and laminated to 2 layers of grade 4 OSB. The radii varied from 1800mm to flat and changed in the length of some of them. They were then cut to profiles which were skewed to prevent the lines of longitude meeting towards the South Pole. A secret fix tongue and groove perimeter detail added that extra frisson. There were very few repeat patterns.

The supporting ribs and related purlins had to be configured to satisfy the same dimensional criteria whilst hanging from the main structural steel trusses. The purlins were 'T' section enabling them to carry load whilst being rotated at varying angles around the curve.

Two layers of plasterboard laid in between the 'legs' supported 100mm of dense quilt to provide the required acoustic protection.

The structure is 22m wide, 12m high and 10m deep extending to some 400m².

Birmingham Medical School

Architects Design Partnership LLP

Sir Robert M^cAlpine Ltd