Savill Garden Gridshell

Completed in 2006 the Savill Building was technically a very demanding structure, and the direct descendant of the Weald and Downland Museum's gridshell building. Once again Steve Corbett (by now called 'Fingers Corbett') was instrumental in the success of the building. New sawn Larch was supplied from the Crown Estates own forests for the timber (50 x 85mm) laths which, like its predecessor the Downland Gridshell, were bonded into continuous lengths using the finger joint, and the structure assembled in situ over a flat scaffold deck. Adjustable props were then manipulated until the structure had achieved its final 3D form. Locking off the structure to the steel ring beam could then be completed along with insertion of blocking and the further 2 layers to make up the 4 layer gridshell. The completed building was so popular that today visitor numbers have more than doubled from 250,000 to over 500,000 per year, proving that a world class building, a historic garden and a cup of tea all together form a visitor attraction not to be missed! We are extremely proud of this innovative, extraordinary oak structure. The building has won an array of awards including The Wood Awards Gold Award as well as the Public Building and Structural categories, and The Institute of Structural Engineers Supreme Award for Structural Excellence (only five of these awards have been given in the last 25 years. Close collaboration was essential from an early stage to manage risk and to ensure the optimum cost, quality and programme was achieved for this truly exceptional timber structure.

Viewed from the garden side. The team included Buro Happold again but this time with Glen Howells Architects performing the role of lead designer. Once more the Green Oak Carpentry Company was selected as specialist carpentry consultants prior to the letting of the main contract for the building.

Internal view. The timber used in the construction of the grid shell was the Crown Estates own Larch, quality was very high and timber often achieved well in excess of C24 grade. As before jointing was carried out from fresh sawn timber using a PU adhesive but this time there was more choice of companies for the finger jointing. The shell structure is over 100 metres long by 32 at its widest point.

View from the garden. The 400x20 CHS steel ring beam is supported on paired steel V shaped supports at 4 points along its length on both sides. The canopy extends beyond the internal envelope creating a covered external seating area on the garden side of the building. The Green Oak Carpentry Company were able to contribute significantly to the design of the roof canopy in finding a way to conceal the extensive steel and LVL fins used in connecting the timber grid to the steel ring beam.

The laths were 85x50mm in four layers separated by large blocking pieces separating layers 1 and 2 from 3 and 4, in effect creating a series of very shallow trussed beams.

This aerial view gives a good impression of the immensity of the structure. The pair of parallel laths in effect delineate the part of the structure that is internal. Two layers of Birch faced ply were applied to the shell structure to assist in locking it together and to stiffen the shell. The layers were bonded and screwed to each other with the addition of steel butt strap to strengthen the joints.

The roof structure is nearing completion...

Finishing touches.