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 roof structures are precast concrete panels supported by precast concrete ribs. 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.
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 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.
The Sydney Opera House includes a number of performance venues: Concert Hall (with 2,679 seats, the home of the Sydney Symphony Orchestra, contains the Sydney Opera House Grand Organ, the largest mechanical tracker action organ in the world, with over 10,000 pipes); the Joan Sutherland Theatre:(a proscenium theatre with 1,507 seats, home of Opera Australia and The Australian Ballet, known as the Opera Theare until 16 October 2012); the Drama Theatre (a proscenium theatre with 544 seats used by the Sydney Theatre Company), the Playhouse (An end-stage theatre with 398 seats) and the Studio (a flexible space with 280 permanent seats -some of which can be folded up- and a maximum capacity of 400, depending on configuration).