Assemble has opened Sugarhouse Studios amid a cluster of former industrial warehouses in Stratford, lying in the shadow of the Olympic Park and unsightly residential developments. It is part workspace for the young architecture collective, and part public space with a cinema, coffee house and pizza joint. On the day we met, a clipboard-wielding health inspector was eyeing up their kitchen.

Meanwhile, Maria Lisogorskaya offered me a stonebaked pizza. None of the Cambridge architecture graduates in this collective — which at one point claimed to have more than 20 members — could have expected to be running such an operation back in 2010, when they found an article about the thousands of abandoned petrol stations in England and decided to find one and turn it into a project.

The Cineroleum came into being after months of research and meetings, as well as charming and cajoling the necessary players. The team of friends found a willing owner of an empty petrol station in East London and enough materials, and figured out how to design and self-build a fully operational, ticketed public cinema.

Their second screening-related project to rehouse a cinema — the community-led Folly for a Flyover — resulted in some fascinating strategic conversations with local authorities. Amica Dall, one of Assemble's seven permanent members, says: "It grew from our original pitch to a much more developed and spiralling project about setting up something in Stratford to address some of the issues of the area. Basically, we went from a place where we would pay rent to a grant agreement to deliver a series of projects based here."

From Sugarhouse Studios, the seven members of the core group are working on policies for the local area, running workshops with schoolchildren and helping to get things made with their project Make, Don't Make Do.

Things become interesting with the square at New Addington — a commission from Croydon Council. Dall continues: "The brief was to do works to create a new town square and high street, and then host a spectacular series of events. Our move was to do the events first, meet the people, find out more about the area and what people who would never come to a consultation meeting really want." They staged Zumba classes on the old public square, built skate ramps and a stage, and prototyped all of their proposed improvements in real time, with a kind of try-before-you-buy approach to master planning.

One of the most positive results was the flood of feedback about the much-antagonised proposal to build skate ramps. Lewis Jones comments, "There was a Facebook page set up — people just said it's great to see kids being kids."