The theatre has undergone many dramatic stages and major changes. The original drawings of the theatre were made by the Swedish engineer Georg Theodor Chiewitz, but that story remained short. The fire that broke out on 8 May 1863 resulted in an almost complete destruction of the building. Only the semi-circular walls remained, and they still give the building its characteristic shape. It is true that the theatre’s architecture was never particularly appreciated – the house was described as being ”a big turtle crawled up to bask on the Esplanade green”. However, the fire was still perceived as a disaster by the Helsinki theatre audience.
Only three years later, in October 1866, a newly renovated theatre house stood ready, now in a slightly slimmer design and with the Russian architect Nikolai Benois’ beautiful salon in gold and red as the heart of the building. The salon has remained relatively unchanged through all the stages of rebuilding that the theatre has undergone since then. Over the decades, also Benois’ theatre building became too small and no longer met the increased requirements. Authorities repeatedly threatened to close down the theatre due to a fire hazard.
During 1935–1936, the house was radically modernized by the famous architects Eero Saarinen and Jarl Eklund. Eero Saarinen’s father, Eliel Saarinen, had already twenty years earlier been involved in the project, but it had then been put on hold for economic reasons. The house was enlarged and now had two side wings. The facade was stripped simple. ”The Swedish theatre is beautiful as an armoured cruiser” expressed an assessor at the opening ceremony in September 1936.
The following extensive renovation, which was conducted in the 1980s, was made in stages so that work mainly took place during summers, in order not to affect the theatre’s business to any notable degree. In 1991, when the house celebrated its 125th anniversary, the façade took a step back towards its original appearance, when the windows of the ground floor were reopened, and a café was opened in the ground floor lobby. The architect for the thorough rebuilding of the theatre during 2010–2012 was Stefan Ahlman.