11 Diagonal Street

11 Diagonal Street
A view of the building from street level
General information
StatusCompleted
TypeMulti use, Office
LocationJohannesburg, South Africa
Coordinates26°12′15″S 28°2′9″E / 26.20417°S 28.03583°E / -26.20417; 28.03583
Construction started1981
Completed1983
Opening1984
CostR65 million
OwnerRebosis Property Fund
Height
Antenna spire80 m (260 ft)
Roof75 m (246 ft)
Top floor75 m (246 ft)
Technical details
Floor count20
Floor area20,000 m2 (220,000 sq ft)
Lifts/elevators6
Design and construction
Architect(s)Helmut Jahn

11 Diagonal Street (also known as the diamond building) is an iconic office tower in downtown Johannesburg, South Africa, that was built by Anglo American Property Services. The 22 floor building is the 15th tallest in the city and it was conceptualized in 1981 and excavations began in December that year. Construction ended in 1983 and the building was tenanted in 1984. The building is designed to look like a diamond as it reflects different views of the Central Business District from each angle of the building. Apart from its unique exterior, the structure was built with concrete instead of steel, demonstrating that concrete could be used instead of steel in both speed and cost.

The building's architect was Helmut Jahn and is featured on the Level 42 album cover The Very Best of Level 42.