L3 Warehouse – Makasiini L3

Urban Dream Management and Tuomas Siitonen office collaborate on creating a concept plan and preliminary architectural design for the future use of L3 harbor warehouse in Jätkäsaari, Helsinki. Our client is Cable Factory, to whom the City of Helsinki, the owner of L3, has granted a reservation for investigating the future development possibilities of L3 with an emphasis of public and cultural use.

The warehouse, built in 1924 and drawn by architect Lars Sonck, is one of the few remaining historical buildings in the former harbor area of Jätkäsaari, which is rapidly being rebuilt into a mixed-use neighborhood close to central Helsinki. The warehouse remained unused in 2008, when the Jätkäsaari harbor was relocated to eastern Helsinki. Since 2010, various temporary uses, such as art galleries, shared workspaces, antique shops and various events, have gradually developed in L3 and the building is now known as a cultural location in Jätkäsaari. However, the long term plans and ownership have been unclear.

A main principle in our planning process has been to include a variety of stakeholders in discussing possible future uses of L3. Cable Factory opened this dialogue in spring 2016 with an open ideation event. In fall 2016 we organised a public open workshop for Jätkäsaari residents. Since then, dialogue has been continued through meetings and tours in the building with a variety of potential future users, entrepreneurs and institutions.

The plans are about to be finished by the end of 2017; more information will be updated here.


  • Client: Cable Factory
  • Team: Hella Hernberg, Tuomas Siitonen (Tuomas Siitonen Office), Paula Karlsson
  • Timeline: 2016- (ongoing)
  • Photos: Hella Hernberg, Aino Huovio /Helsinki Design Week, Sudar Oli Gunasekaran