Weathered Radial Timber Complements Aussie Garden
Project NameCranbourne Botanic Gardens Visitor Centre
The Australian Garden at the Royal Botanic Gardens Cranbourne features a number of exhibition gardens, sculptures and displays that showcase the beauty and diversity of Australian plants and their landscape.
The $5M Visitor Centre, located at the entrance to the Australian Garden, provides an information service, toilets, indoor/outdoor café and retail space. The weathered timbered building has been designed to give a tree top experience for visitors, offering glimpses of both the remnant bushland and the Australian Garden.
The complex was completed in two stages, the first in 2005 and the second in 2009. Architect, Kerstin Thompson, did not want to overwhelm the gardens. A pared back design, simple construction methods and the use of low key materials has allowed the gardens to stay the primary focus. By specifying recycled and sustainable timber products, Kerstin has maintained the site's environmental integrity and the Visitor Centre sits modestly, as an extension of its landscape.
Many key principles of sustainable design were employed and these environmental systems were kept obvious and simple enough that the public could replicate them at home.
Careful consideration was given to levels and construction methods to minimise disruption to the site's ecology. Not just a solid mass on the landscape, the integrated design produces a prism - a series of interior spaces connected by timber decks and ramps. The monochromatic use of timber appears to make walls and decks as one, carrying the visitors along through the entrance.
The use of passive design principles, orientation and screening and glazing configurations maximised natural light, minimised solar gain and provided cross-flow ventilation. The Visitor Centre does not rely on elaborate mechanical systems for its high level of environmental performance. The use of slatted timber eaves and screens to control sunlight is delightfully simple. The architect proudly boasts the use of recycled local hardwood (Ironbark) for the doors and windows due to its low embodied energy and rustic character. The richness of timber meant the structure could be left unadorned and at one with its environs. Weathered grey cladding looks at home against the brilliant red Aussie dust.
The architect's challenge was to provide a way of apprehending the Australian landscape's diversity and richness. The buildings were to be a means of experiencing the topography and ecology of the site. Kerstin Thompson, the architect, said, "Our palette of materials consolidates this vision - weathered timber boards both allow the buildings to recede and provide a canvas against which to see the changing shape, colours and shade of the plants that are unique to an Australian sense of place."
The Visitors Centre is clad with the highly durable and economical Radial Timber Square Edge Weatherboard cladding system. Radial Timber ticked all the right boxes; sourced locally, sustainably harvested and low on wastage. The timber used for this project is class 2 durability Silvertop Ash, which is also a bushfire resistant timber. Screens were used as architectural highlights as well as for sun screening.
In keeping with the architect's vision the interiors enable maximum interface between inside and outside. High thermal mass and cross-flow ventilation keeps the interior spaces breathing and porous, responsive to climatic variation. Open and protected, the building can change with the seasons and provide a healthy environment for staff and visitors. The slatted timber ceilings create a warm and intimate ambience. Dappled light from the external pergolas filters gently through to the interior.
Timbers used in this case study:
Ceiling battens of Silvertop Ash radial timber
Laminated recycled Ironbark
Radial timber Radcon weatherboards in Silvertop Ash
Armour Ply plywood