Windmill Hill

Completed in 2012, the structure features stressed skin diagrid trusses leant against each other to form the planes of the roof, an ingenious plan. The trusses were built from 300 x 70mm oak glulam beams with crown cut oak veneers, and with stepped housing joints. Each roof section was made up of primary, secondary, and tertiary beams, all precision CNC cut and jointed.

A large sliding roof kept the timber dry during the assembly. The lower visible layer of ply had oak veneers and was cut to follow the form of the diagrid. The upper layer of ply consisted of eight 1.2 x 2.4 metre sheets of ply bonded together in the factory to form a single 9.6 x 2.4 metre sheet, to achieve maximum strength by minimising butt joints.

When the client was asked about tolerances, he replied saying that he wanted the roof to achieve the look of a piece of fine furniture. This is where CNC processes came into their own and careful coordination was essential. The choice of veneers was made and carefully applied to achieve the look of solid oak beams but with the controlled moisture content and stability of glulam.

Vertical timber staves create a Brise Soleil, minimizing solar gain and glare.

Collaboration between architect, engineer, carpenter and builder were essential and the craftsmanship throughout exceptional.  

The structure won the prestigious Wood Awards Gold among others, with the prize giving ceremony being held at Carpenters’ Hall in the City of London, the home of the Carpenters’ Company.