Peter G. Rolland to direct civil engineers, a reversal of the traditional roles in Australia. Rolland played a pivotal role in the design, development and coordination of all surface elements including pool design, paving, conceptual lighting and artwork locations. Horticultural experts from the Australian National Botanic Gardens and a government nursery were consulted on plant selection. Permanent irrigation has been limited to only the more formal areas. Irwinconsult was commissioned to provide structural engineering, including quality assurance of all structural elements, to deliver a building with a designed lifespan of 200 years. Construction began in 1981, and the House was intended to be ready by Australia Day, 1988, the 200th anniversary of European settlement in Australia. It was expected to cost . Neither the deadline nor the budget was met. In 1983, Mitchell/Giurgola & Thorp, commissioned the forecourt mosaic, Possum and Wallaby Dreaming, which Aboriginal Australian artist Michael Nelson Jagamarra, of Papunya, Northern Territory, based on his painting of the same name. The mosaic shows "a gathering of a large group of people from the kangaroo, wallaby and goanna ancestors [who] are meeting to talk and to enact ceremonial obligations. The work derives from the sand-painting tradition of the Warlpiri people, and has complex layers of meaning known only to Warlpiri elders". Three stonemasons took 18 months to two years to hand-cut the 90,000 granite setts which were used in the artwork. The mosaic was digitised in April 2019 from a series of photographs taken from five metres above the artwork. The building was opened by Queen Elizabeth II on 1988, the anniversary of the opening of both the first Federal Parliament in Melbourne on 1901 by the Duke of Cornwall and York (later King George V), and of the Provisional Parliament House in Canberra on 1927 by the Duke of York (later King George VI). The flag flown from the flagpole is , about the size of half a tennis court. The flagpole weighs 250 tonnes and is made of polished stainless steel from Wollongong. It was designed to be the pinnacle of Parliament House and is an easily recognisable symbol of national government. It is visible by day from outside and inside Parliament House and floodlit at night. The flag itself weighs approximately . The site covers . The building was designed to sit above Old Parliament House when seen from a distance. The building is four metres