Building J/K offers space for: 

• Educational spaces for the REC faculties.  
• The Computational Social Science programme. 
• REC Impact, an initiative of the faculties of Economics and Business, Social and Behavioural Sciences, and Law, aimed at valorising education and research at these faculties. The Impact hub consists of (flexible) workplaces, offices and a conference room. 
• Study workplaces of the University Library. 
• Offices of Innovation Exchange Amsterdam (IXA), knowledge institute for language development ITTA, On Campus, Folia, Facility Services. 
• Espresso bar Coffee Star. 

The teaching spaces of building J/K were focused on their former use as a laboratory. The building was also outdated, for example in terms of fire safety and accessibility. The key points of the design were therefore the realisation of new teaching spaces for a broad group of students, and making the building future-proof. The building also received a prominent new entrance at Nieuwe Achtergracht 184, the main thoroughfare of the campus. 

To make building J/K sustainable, future-proof and energy-efficient, the following measures have been taken: 

• All lights in J/K are LED lighting. 
• The building is heated and cooled with a heat pump with connection to the heat-cold storage. 
• The low-rise building has secondary glazing to improve the climate.

In the first half of the 20th century, Roeterseiland was used as a tram depot, among other things. Due to the higher student numbers, the UvA built new buildings in the 1960s, including REC J/K. This building was used as a physics laboratory. With its brick chimney, it is a characteristic building on the Roeterseiland Campus.