Savill Gridshell

 Completed in 2006, the technically demanding Savill Building, was a direct descendant of the Weald and Downland Museum gridshell, instead of oak, it utilised fresh sawn Larch for the laths (50 x 85mm) from Crown Estates’ forests. As before these were finger-jointed and feather scarfed into continuous lengths and assembled in situ over a scaffold deck, the final 3D form being achieved using adjustable Peri formworks props. The structure, composed of four layers of laths separated by blocking, was bolted to steel and LVL fins fixed to the 400 x 20mm CHS steel ring beam.

Glenn Howells Architects led the design team in collaboration with Buro Happold, with the Green Oak Carpentry Company acting as specialist carpentry consultants. A similar team dynamic to the Downland Gridshell grew out of early appointment of the carpentry team post planning, enabling participation in the detailed design. The carpenters were able to make significant contributions to the design, including the roof over-sail, fixing the shell structure to the ring beam and manufacture of the ring beam avoiding doubly curved sections to save cost and complexity in manufacture.

The Crown Estates’ Larch was of exceptional quality, comfortably making C24 grade. The carpenters were part of the selection process of the standing timber, once common practice historically. The shell spans over 100 meters in length and 32 meters at its widest point.  The CHS steel ring beam was supported by pairs of inverted V-shaped steel supports, the roof cantilevering to form a covered external seating area. The Green Oak Carpentry Company employed Buro Happold as engineers and co-designers of the gridshell roof.

Awards include a RIBA regional award, the Stirling Prize shortlist, the Wood Awards Gold Award, and the Institute of Structural Engineers Supreme Award, only given in years in which an exceptional project merits recognition.

"So what you have is effectively a great big weather-sealed canopy, perched on dynamically angled steel legs. It is the ultimate summerhouse, the granddaddy of gazebos." Hugh Pearman