“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”, says Winy Maas, founding partner of MVRDV. “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.”

A particular challenge of the design was to be able to heat the pool space sufficiently and sustainably, while also protecting the historic materials from the humidity of the pool. To solve this, the glass walls surrounding the pool create a compartmentalising effect to protect the stained glass and the works of art. The roof of the church will be insulated from the outside, preventing excessive heat loss while maintaining the view of the original brickwork from the inside. After insulation, the existing roof covering will be put back in place. The wooden roof will be retained and fitted with sound-absorbing panels for better acoustics. The technical installations have been discreetly incorporated with air handling units in the basement. This approach ensures an energy-efficient and comfortable indoor climate, while preserving the historical elements of the church as much as possible.

The design for Holy Water was created through a collaboration between MVRDV, Zecc Architecten, IMd Raadgevende Ingenieurs, Nelissen Ingenieursbureau and construction economics consultancy SkaaL. The first dive is expected to take place at the end of 2027.