linguistic:voice_change, stylistic:tone
Description

The facility features a modern expressionist design, with a series of large precast concrete "shells", each composed of sections of a sphere of 75.2 metres (246 ft 8.6 in) radius, forming the roofs of the structure, set on a monumental podium. The building covers 1.8 hectares (4.4 acres) of land and is 183 m (600 ft) long and 120 m (394 ft) wide at its widest point. It is supported on 588 concrete piers sunk as much as 25 m (82 ft) below sea level. The highest roof point is 67 metres above sea-level which is the same height as that of a 22-storey building. The roof is made of 2,194 pre-cast concrete sections, which weigh up to 15 tonnes each.

Although the roof structures are commonly referred to as "shells" (as in this article), they are precast concrete panels supported by precast concrete ribs, not shells in a strictly structural sense. Though the shells appear uniformly white from a distance, they actually feature a subtle chevron pattern composed of 1,056,006 tiles in two colours: glossy white and matte cream. The tiles were manufactured by the Swedish company Höganäs AB which generally produced stoneware tiles for the paper-mill industry.

Apart from the tile of the shells and the glass curtain walls of the foyer spaces, the building's exterior is largely clad with aggregate panels composed of pink granite quarried at Tarana. Significant interior surface treatments also include off-form concrete, Australian white birch plywood supplied from Wauchope in northern New South Wales, and brush box glulam.

Of the two larger spaces, the Concert Hall is in the western group of shells, the Joan Sutherland Theatre in the eastern group. The scale of the shells was chosen to reflect the internal height requirements, with low entrance spaces, rising over the seating areas up to the high stage towers. The smaller venues (the Drama Theatre, the Playhouse and the Studio) are within the podium, beneath the Concert Hall. A smaller group of shells set to the western side of the Monumental Steps houses the Bennelong Restaurant. The podium is surrounded by substantial open public spaces, and the large stone-paved forecourt area with the adjacent monumental steps is regularly used as a performance space.