The UK’s largest timber gridshell structure, the roof of The Crown Estate’s new Savill Building at Windsor Great Park in Berkshire, has been officially opened by HRH the Duke of Edinburgh. Buro Happold provided the structural engineering design for the roof of the building – a spectacular yet graceful, 90m long by 25m wide three-domed undulating timber structure – which will form a new focal point for the park.

As well as the flowing shape of the exterior, intended to mirror the skyline created by the trees surrounding the structure, the gently curving grid of the timber gridshell – clearly visible on the inside – provides another impressive view of the building. Having the structure on display gives a remarkable insight into the way the roof works and proves that a building’s structure and interior can be as graceful as its exterior.

The building, located in the Savill Gardens in the south-eastern corner of Windsor Great Park, houses a ticket office, shop, self-service restaurant, seminar rooms, offices and a small garden centre.

The brief from the client, The Crown Estate, created some seemingly contradictory demands which are met by the choice of the timber gridshell. The roof uses the latest technology and engineering expertise alongside traditional craft skills to create a structure which is dramatic yet sensitive to its surroundings. Buro Happold engineers worked closely with the team at Glenn Howells Architects, to successfully create a structure made of timber sustainably harvested from the woodlands of Windsor Great Park.

More than 20km of 80mm by 50mm larch timber is used in the gridshell. The gridshell roof structure weighs 30 tonnes – much less than a similar roof in concrete, reducing the loads on the legs and foundations.

This is the latest timber gridshell that Buro Happold has designed, continuing a lineage of lightweight, environmentally sensitive structures that goes right back to the practice’s roots 30 years ago. The design of this gridshell builds on the experience gained in the engineering of the Downland gridshell at the Weald and Downland Museum in Sussex, completed in 2002. An artefact store and workshop for the museum, it was the first large timber structure to be built in the UK but is a quarter of the size of the Savill Building. The Savill Building project reunited Buro Happold with the Green Oak Carpentry Company (GOCC), the woodwork specialist which also worked on the Downland gridshell.