Short on cash but with an abundance of devoted fans, club officials appealed for help when they were granted permission for construction work at their Alte Foersterei (Old Forestry) stadium.
Tucked away in the leafy southeast Berlin suburb of Koepenick, the stadium with its trademark old forest warden's office has been the home of the club since 1920.
Hundreds of fans volunteered after the call last June, offering their spare time, equipment, building material and experience. Fan commitment brought in close to five million euros' worth of work and resources.
"Our club, our stadium, our pitch, the Alte Foersterei," one volunteer worker wrote on the team blog on their website.
"The response from fans was stunning," said club spokesman Christian Arbeit. "Everyone started spending their holidays, their days off here. Others came on weekends, students worked during their semester breaks; absolutely stunning."
"The stadium becomes much more valuable this way. It carries more weight than one that was built by a big corporation," said Arbeit.
"This was always a club that had an alternative culture," Arbeit said. "It was not a club of resistance fighters but it was a club where people did not agree with everything in the GDR and they made their disagreement known."
Unlike hated East Berlin rivals Dynamo, the feared Stasi secret police team, the "Iron Union" attracted dissent.
"You came here if you had an alternative position, an alternative lifestyle. Nowadays it is all about opposing this commercialisation of sport," Arbeit told Reuters.
