Mecanoo’s gatehouse to Holland’s Keukenhof flower garden employs a visually striking engineered timber roof structure
Mecanoo’s gatehouse at Keukenhof in Lisse, Holland, is designed to welcome visitors during the springtime opening of the world’s largest flower gardens. Organised around landscaped plazas, ponds and seating terraces, the 3200-square-metre scheme includes visitor facilities, a restaurant, offices and retail spaces. A stepped timber roof spans between two volumes, marking the gateway and providing protection from the elements.
‘The gatehouse provides a transition between the outside world and that of Keukenhof and all its flowers’, explains the architect. ‘Walking through the entrance, you can see the sky framed by the timber triangles above. Look down and you can see an intriguing pattern of triangular shadows on the ground.’
The larger two-storey building makes extensive use of natural materials including timber, copper cladding and brick. Much of its glazed ground-floor facade can be opened up to blur the distinction between inside and out. Generous skylights create a spacious and light atmosphere in the restaurant, while the first-floor offices provide extensive views over the gardens.
The cascading roof comprises five interlinked platforms, each measuring 21.6-metres-wide and accommodating a height difference of 1.6 metres. The structure is divided into beams and stressed-skin box beams. Measuring 1.2-metres high, the cross-laminated pinewood beams span the entire width of the building, as well as the column-free span between the two supporting volumes. The height of the beams helps to achieve the 21.6 metre column-free area as well as cantilevers of up to 10-metres across.
The stressed-skin box beams are positioned between the structural beams creating a triangular pattern. They not only reduce the overall weight of the structure, but also facilitate the integration of insulation, power, and LED light fittings. Where the roofs step-up a 2.8-metre-high structural beam connects the adjacent platforms as well as a 400mm parapet. The project contains a total of 850 cubic metres of wood.