Summer 2022 brought scorching temperatures to Bochum, making the outdoor pool a welcome refuge. The reopening of the Werne district's renovated 1930s pool complex—featuring a 50-metre competition pool, an adventure pool, and a toddler splash area—arrived at the perfect moment. Remarkably, the entire facility was back in operation just nine months after modernisation began. Stuttgart-based 4a Architects collaborated with Pool out of the Box as the general contractor to deliver this achievement using modular construction techniques. The result: significant time and cost savings, plus the bonus of a quieter neighbourhood—construction noise kept to a minimum.

The redesign of the administrative area, changing rooms, sanitary facilities, and storage and technical spaces relied on twenty prefabricated steel and wood modules—complete with insulation and interior components. Upon arrival on-site, a crane carefully positioned each module onto the prepared foundation slab and secured it in place. The changing rooms and lockers orient toward the pool grounds, positioned freely beneath the cantilevered roof between the administrative and sanitary facilities. All spaces maintain a consistent 3.95-metre ceiling height, with depth individually tailored to specific functional needs. The exterior features a rear-ventilated façade of vertical, pre-weathered rough-sawn spruce slats. To maximise daylight, every second slat in the upper third of the cladding has been omitted. The roof—a laminated board deck—rests on the modules and extends across the outdoor areas, while a three-layer insulated panel guards against summer heat gain and winter frost damage.

Replacing the deteriorating concrete pools with stainless steel basins further bolstered cost efficiency. This transformation reduced the water surface area from 3,000 m² to approximately 1,580 m². Energy-saving technology, including a solar absorber system, delivers ongoing operational savings. The facility also eliminated its wave slide to streamline maintenance. Since the pool operates exclusively during summer months, heating serves only the staff facilities and frost protection in winter. Natural ventilation flows through operable vents in the skylight bands and parapet areas of the operations office and staff rooms.

www.4a-architekten.de
www.pooloutofthebox.de

Photography:

David Matthiessen
www.davidmatthiessen.com

(Published in CUBE Ruhrgebiet 03|22)