Inhabiting with Daylight - From prison to everyday living

Position within the Masterplan

Vridsløselille Prison served as a state prison for more than 150 years before closing in 2016. The site is currently undergoing a large-scale redevelopment based on an approved masterplan, which will create a new residential district on the former prison site. This project follows the overall vision of the masterplan while proposing a different approach to the prison wings. Instead of demolishing and rebuilding the radial wings as proposed in the masterplan, the project explores how the existing prison wings can be transformed into housing through adaptive reuse.

The Lost Daylight

Originally designed as a radial surveillance-based prison, the central hall and the prison wings formed one continuous open space, allowing daylight to reach the ground floor. The major renovation between 1961 and 1985 inserted new floor slabs, interrupting this vertical connection. Today, only the upper corridors receive natural light, while the lower floors and the central hall depend largely on artificial lighting. 

This became the starting point of the project: How can daylight be brought back into the building?

From Daylight Analysis to Spatial Strategy

Daylight consists of three types: sunlight, skylight and reflected light. In Denmark, skylight is often the dominant daylight resource due to frequent cloud cover and high latitude.

The daylight analysis revealed different conditions across the four prison wings. Wings A and D share a similar situation, with limited direct sunlight on their north-facing facades, while wings B and C receive sunlight from both sides at different times of the day. The shadow studies also showed that the upper levels and end parts of the buildings receive more consistent sunlight, while the lower floors near the central hall are more shaded. These findings led to the first spatial ideas: apartments that open from north to south to bring light across the depth of the building, two-storey apartments to improve daylight duration on the lower floors, and smaller single-sided apartments for areas with better existing daylight conditions.

Building on the cell-based typologies observed on site, the square metre study explored combinations of the original cell modules for housing. Together, these studies led to three selected unit types: single-level units, double-height units and through-units.

The spatial organization was developed through an iterative process of sketching, work model making and daylight testing. The work models were tested in the light lab using simulated skylight, focusing on how daylight penetrates and distributes within the interior.

Based on the previous daylight analysis, two spatial organization strategies were developed for the different wing conditions. In wings A and D, through-units extend across the depth of the wing, allowing daylight from both north and south sides, while three-storey light wells bring skylight down into the building and support shared spaces on the ground floor. In wings B and C, the apartment units remain within the original prison cell positions, while a new circulation system is inserted along the inner side of the wing. This creates an interior street-like corridor, with light wells bringing skylight deeper into the building and highlighting the apartment entrances.

At the scale of the housing complex, the first floor plan shows how the two spatial strategies are applied across the four wings. Each wing has its main independent entrance and vertical circulation at the semi-circular end, providing daily access for residents. In the central hall, two shared vertical cores connect pairs of wings and provide access to the shared spaces, maintaining the central hall as a collective space within the complex.

The apartment units are developed from the original cell structure and tested through plan layouts and VELUX daylight visualizations. Former cell door openings are transformed into internal windows, allowing skylight from the corridor to enter and improve daylight distribution within the units. The original single cell is shown as a comparison, showing the change from a confined space with single-sided daylight to proposed housing units with more open and varied daylight conditions.

The window and detail interventions work with the existing 50-centimetre-thick walls and the traces of the former cell structure. On the façade, lowered windowsills create seating niches inside the apartments, while expanded balcony openings form small outdoor spaces within the depth of the wall. On the interior elevation, recessed new walls preserve traces of the original cell doors, and wooden slat acoustic panels are added along the corridor side to reduce sound reflection in the hall. For the inserted walkway, an independent self-supporting steel structure allows parts of the existing solid floor to be removed, opening up the space while keeping the new circulation system structurally separate.

For the balcony detail, the original window width is kept on the façade, while the thick wall is cut diagonally to widen the interior opening and allow more daylight into the room. For some corridor-facing internal windows, an angled sill is used to balance daylight and privacy, allowing skylight to enter while limiting direct views from the corridor. The 1:20 unit model shows how these interventions affect daylight penetration and the light and shadow atmosphere inside.