The name of the building is a pun: it can mean dipole in Finnish, but also "the second Poly", the second building of the polytechnic students. The original Polytechnic Students' Union, now called the "Old Poly", was a National Romantic building located on Lönnrotinkatu in Helsinki that was left behind when the university moved to Otaniemi.
History
When Helsinki University of Technology moved from Helsinki to Espoo in the early 1960s, an architecture competition was held for what would become the new building for the Student Union of the university. Due to the challenging rocky location and adaptability requirements none of the competition entries fulfilled all the jury's demands and the first prize was not given. The second prize was shared by the architect couple Reima and Raili Pietilä and Osmo Lappo who were asked to further develop their proposals. In the end the 1961 design by Pietiläs was used as the basis for the design of the Dipoli building. Work began in 1965, and the building was ready for use in autumn 1966. In 1993 the building was transformed into a training centre of the university due to high maintenance costs. Besides its primary role, Dipoli is still regularly used for conventions, congresses and student parties. The building houses over 20 conference rooms and auditoriums. Dipoli was owned by the student union of Aalto University until 2013 when it was announced that the building would be sold to the university itself for an undisclosed sum. The building was extensively renovated between 2015 and 2017 turning it into the new main building for the university. The refurbished building includes an auditorium, restaurants and exhibitions spaces. The university's management also works in Dipoli.
Architecture
The building uses extensively materials from Finnish nature, such as pine wood, copper, and natural rocks. Dipoli has 500 windows of which only four are identical. The architects originally planned for as little interference with the natural granite of the site as possible; but blasting the hard granite base rockinevitably fragmented it. The building is seen as a key example of organic architecture. Reima Pietilä himself said of the building:
