“Any special skills? Metal work, carpentry?” the man with the clipboard asked me, without irony.

Work at the Alte Försterei stadium in Berlin’s Köpenick district started every day at 7 am. It was nearing completion – only the pitch heating system needed to be installed while the club was awaiting delivery of a roof to fit on top of the gleaming white stands.

A lady behind the clipboard man had already looked me up and down, and she spared my apologies. “It’s alright, I’ve already got him down for the painting,” she said. I was duly set the task of giving the ladies’ toilet a new white coat. I had hoped for a go on the welding iron, or maybe a circular saw, but did not push the issue, accepting my unskilled beta-male status without fuss.

The renovation of the old stadium, which took the whole of last season and continued into the summer break, points to the ambitions of Eisern Union. Their relegation to the regional leagues in 2004 had been an abject humiliation for a team that had played in the UEFA Cup – thanks to a runners-up place in the German Cup – only three years earlier.

But re-entry into Germany’s top leagues requires more than footballing prowess – it requires a stadium that meets certain technical guidelines – pitch heating, a roofed terrace, a certain percentage of seated places – and the club decided to prepare early. As fate would have it, the team won the new third division at a canter this season and will break in its new stadium in the Bundesliga’s second tier. The inaugural match will be a friendly against Berlin’s only first division club Hertha BSC on July 8.

The man with the clipboard took my particulars and pointed me and another newcomer, Eberhard, to the paint and the ladies’ room. “Breakfast is at 9, lunch is at 12. Sandwiches cost 10 cents.” About fifty other men were already gathered beneath the old stand, now looking incongruously decrepit next to the white steel skeleton around us.

“Welcome to the best building site in the world!” proclaimed Sylvia Weisheit, a bustling middle-aged lady and pep-talk specialist. The gathered masses, standing around snacking on coffee and cake, displayed an earnest reserve not typical to builders. After Sylvia delivered a cheery status update, we dispersed and Eberhard and I made our way to share a morning of proletarian solidarity in the toilet.

The sense of community in this singular project was palpable on that rainy morning, and it was expressed mainly through food. A group of women, the Fußballmuttis, or football mums, provided three balanced meals in a tent adjoining the stadium’s modest VIP area. There was even ice cream.

Änne Troester, a Prenzlauer Berg-based volunteer who comes out regularly to help with the meals showed a typical Union enthusiasm: “There seems to be a unique connection between the fans and their club, it’s very Berlin. Like they own the club; they simply take the right to have a say in what the club does. And the fans’ gesture was incredibly generous.”

The snowballing success of the labour-donation campaign has taken everyone by surprise, and it has had a, well, concrete benefit. At last count, some 1,800 volunteers have contributed a total of 80,000 hours’ work. This is estimated to be worth €2.5 million – half the total cost. The success is apparently driven by shame – when fans gather on the stands for next season’s home matches, no-one wants to be among those who didn’t help out.

The club’s spokesman Christian Arbeit also admits that the project was born of necessity. “There was an element of desperation. Berlin is a city heavily in debt. Most cities finance their new stadiums, but in Berlin Hertha’s massive World Cup stadium exhausted the budget and the political will. Instead, the city offered us the Jahn-Sportpark in Prenzlauer Berg, which, with the addition of pitch heating, would have been acceptable for the second division Bundesliga.”

But, mainly for emotional reasons, this was not an option. In communist East Germany, the Jahn-Sportpark was the home ground of BFC Dynamo, archrivals of Eisern. The bitterness between the clubs had a political edge to it. Dynamo, serial winners of the East German league, and backed by the head of the secret police the Stasi, stood for the political elite. Those of an anti-authoritarian bent gravitated to Eisern Union.

So although the Jahn-Sportpark was accepted as a temporary home for last season, and was the stage of their biggest success in recent years, it was the last place Eisern could move to permanently.

Union’s dissident history also explains the healthy mix of sub-cultures represented among the fans. The eastern German working classes that live around Köpenick make up the majority, but they are interspersed with punks and students. This is reflected in the club’s theme song, a pounding synth-pop track that segues into metal guitar performed by German music icon and Eisern fan Nina Hagen.

This demographic showed up at the building site too. At lunchtime in the makeshift canteen, there was a pale, scrawny boy at the next table, masked slightly by his piercings. With his head low over his meat and potato soup, he spoke to no one. On his bedraggled coat there was a patch that read, “Shitting Is Work.” It seemed to offer a wise perspective on the heavy lifting going on all around. Defecation, the scrawny boy was inadvertently implying, was more work than this, a labour of collective love.

Eberhard alongside me surveyed the boy philosophically. He turned to me and uttered further wisdom on the camaraderie all around. “Well, one day at Eisern is like a year’s worth of integration,” he said. It wasn’t really true, but I can see what he meant.

1. FC Eisern Union’s refurbished stadium at the Alte Försterei will be inaugurated on July 8 with a friendly match against Hertha BSC. This has already sold out, but tickets are still available for further exhibition matches against Schalke 04 on July 25 and Bayern Munich on August 26.