Built over a hundred years ago, the St. Francis of Assisi Church in Heerlen, in the southern Netherlands, ceased hosting religious services in 2023, allowing the municipality to redefine its use. The conversion of this national monument into a public swimming pool responds to the growing demand for the city's existing aquatic centres, while also giving new life to this iconic building, easily recognisable by its silhouette in the city centre. The transformation is part of a broader renovation plan for Heerlen's city centre, which includes the opening of a Roman Catholic museum and the renovation of the Royal-Rivoli cinema.
The design by MVRDV and Zecc Architecten incorporates an illuminated circular canopy marking the main entrance, alluding to the building's ecclesiastical past and serving as a contemporary gesture linking the old with the new. Once inside, visitors walk through the aisles to access the changing rooms or the catering area, located at the rear of the church. Glass walls separate these paths from the central space, where the heated pool is located.
Rendering. New public swimming pool in Heerlen by MVRDV and Zecc.
Longitudinal section. New public swimming pool in Heerlen by MVRDV and Zecc.
To accommodate the new pool, the existing pavement will be carefully dismantled. The old church pews will be repurposed and integrated into the glass walls that enclose the pool area: on one side, they will provide seating for swimmers, and on the other, they will function as bars for spectators. The old pulpit will also be transformed, taking on a new function as a lifeguard station.
The pool floor will be height-adjustable, allowing the space to be adapted to a variety of activities and users of different ages and abilities. In its highest position, the floor will completely cover the pool, restoring a flat surface that will allow the space to be used for social and cultural activities. Furthermore, the pool area can be filled with a thin layer of water. Combined with appropriate lighting, this layer will reflect the interior of the church, offering visitors the experience of "walking on water."
“The vacancy rate of churches is increasing, so we need to come up with new, creative ideas for what we can do with these buildings. Why not give these churches a social function again, as they used to have? A public swimming pool is ideally suited for this. Imagine: swimming the backstroke with a view of a church vault and stained-glass windows. By covering the entire pool area with a small layer of water, you can also create a beautiful visual effect, allowing the church to return to its original form and appear even larger and more impressive through the reflection.”
Winy Maas, founding partner of MVRDV.
Rendering. New public swimming pool in Heerlen by MVRDV and Zecc.
A new mosaic paving will cover both the pool area and its movable floor. Its design will reference the church's existing colours, materials, and stained-glass windows, establishing a visual link with the original architecture. This mosaic will be developed in collaboration with local artists, paying homage to Heerlen's rich muralist tradition. The lighting above the pool is inspired by the church's original lamps, visible in historical photographs, and its four rows will also function as lane guides for swimmers.
One of the main challenges of the project was to ensure adequate and sustainable climate control of the space, while protecting the historic elements from the humidity generated by the pool. To this end, the glass walls surrounding the pool create a compartmentalised effect that protects the stained-glass windows and artwork. The roof will be insulated from the outside, reducing heat loss without disturbing the view of the original brickwork from the inside. After insulation, the existing roof cladding will be replaced. The wooden structure will be preserved and fitted with sound-absorbing panels to improve acoustics. The technical installations have been discreetly integrated, with air handling units located in the basement. This approach ensures an efficient and comfortable interior environment while fully respecting the building's heritage elements.
