bregenz indoor swimming pool

urban design concept
without a doubt, the outdoor pool complex in bregenz, located directly on lake constance and surrounded by a spacious park, is one of austria’s most impressive open-air swimming facilities.
on sunny days, the outdoor areas experience a massive influx of bathers, as clearly evidenced by the aerial photo attached to the competition documents. the requirement to maintain uninterrupted swimming operations necessitates that the new indoor pool be built on the exclusive grounds of the existing outdoor facility — an intervention that would otherwise result in the loss of valuable lakefront areas. this loss of open space is avoided through the creation of a structure that merges landscape and architecture — a building that not only replaces the green area but even enhances it. the newly created green roof of the swimming hall becomes an optimized sunbathing area for visitors. the outdoor pool and lake constance are thus staged through the formation of a new natural grandstand.

landscape building
the fundamental concept for the new indoor pool envisions the “unfolding” of the existing open areas into a spatial form — creating a bathing hill, a ramp-like, westward-sloping, walkable green surface that forms the roof of the new hall. through this conceptual move, only minimal open space is lost, while the transformed roof areas, shaped like terraces, offer views of the spectacle of nature, water, and sport.

green submarine
the new swimming hall, situated beneath the sloping green landscape, features continuous glazing to the north and south to provide maximum transparency and visual connection. a large opening created by a “counter-swing” in the roof form toward the west visually and spatially links the hall to the existing outdoor facility. the bathing arena thus opens in three directions, while the changing and service areas form a barrier toward the east, adjoining the festival grounds.

bathing arena
from the entrance area, visitors are immediately greeted with generous views into the hall. the interior topography is subtly articulated into varying levels, creating seating terraces and lounging zones in diverse spatial situations. the competition-standard swimming pool lies at the center of the arena, surrounded by slightly elevated walkways and lounging areas. a gallery running the full length of the hall provides an optimal viewing experience during swimming events, while a secondary 25-meter pool faces toward the outdoor area. separate acoustically buffered zones house the training and therapy pools as well as the slide landing pool. the main sports pool can be temporarily divided by nets and accessed directly from the group changing rooms. the indoor pool, sauna, and outdoor pool each function as independent tariff zones with their own access controls. team and school changing rooms have a dedicated entrance on the east side, ensuring independent access outside regular opening hours.

changing and shower facilities
the changing and sanitary zone runs along the entire northern side of the hall, with multiple short connections to the bathing arena, where the shower and toilet facilities are located.
stairs and elevators directly connect this zone with the sauna landscape above.

lake constance sauna
privacy, exclusivity, and lake views are the defining qualities of the sauna area, ideally situated on the upper floor. the exclusive sauna garden extends over the gently sloping “garden plateau” — a planted ramp — leading past the panorama sauna and earth sauna all the way to the lake. the design ensures views out while screening views in, using subtle planting and visual filters.
the relaxation areas and sauna spaces maintain continuous visual connections to the lake — including the integrated panorama and earth saunas within the garden plateau. the route to the refreshing water is laid out for optimal user comfort. a cut into the large bathing hill form provides additional daylight and creates another protected outdoor relaxation area for the sauna.

entrance hall and gastronomy
both the entrance hall and restaurant are strategically placed.
the entrance hall efficiently manages guest circulation, while the restaurant functions as a central hub serving different visitor groups and their specific needs:
external guests, indoor pool visitors, and seasonal outdoor pool guests, who on peak days are served through self-service facilities. all dining areas — both indoor and outdoor — are positioned directly by the pool with views into the hall.

slide
the starting point for the water slide is located in a dedicated space above the bathing hill. this space is accessible both from indoors via an open staircase within the hall and from outside via the sloping green terrace. the slide’s landing pool is acoustically separated from the main swimming area and includes a direct outdoor exit. during the warm season, access to and from the slide occurs entirely through the outdoor area, keeping the indoor hall unaffected by the slide activity.

structural concept
the load-bearing components of the building — including the substructure, retaining walls, floor slabs, and pool structures — are designed in reinforced concrete. the ground-bearing slabs act as shallow foundations and, together with the surrounding exterior walls and the outdoor pool zone, form a watertight concrete tank up to an elevation of 398.5 meters above sea level. all openings are positioned above this level. the roof structure above the bathing arena and toward the outdoor pool uses round steel trusses supported on concrete shear walls along both sides of the hall, with additional central supports. these trusses carry a roof made of prefabricated timber box elements, approximately 11.0 × 2.7 m in size, allowing rapid installation. the elements are about 50 cm deep and designed to support the natural green roof and public use above.

fire safety and escape routes
at ground level, all zones have direct exits to the outside, ensuring evacuation within 40 meters.
from the sauna and staff areas on the upper floor, one can exit directly into the gently sloped sauna garden — which leads down to ground level — or continue through the recessed garden zone onto the green roof. all areas can thus be evacuated within 40 meters. from the technical floor, all spaces connect within 40 meters to a secure, pressurized escape tunnel leading to the service yard.

building services
ventilation in the main hall is achieved simply via floor-level convectors along all glazed façades, supplying roughly 250 m³/h per meter of façade length to prevent condensation. exhaust air is extracted along the gallery and partially from the sanitary and changing areas.
heat distribution and emission are mainly provided by underfloor heating in all primary occupied spaces.
the service yard, accessible via a ramp on level -1, connects to the technical rooms located below the swimming hall. this area houses workshops, offices, and supply/disposal facilities naturally lit through the ramp. the varying levels of the hall and changing rooms create higher ceilings in the technical zones, allowing the installation of ventilation and filtration systems without complex level changes.

building physics
given the constant indoor climate conditions of 32°C and 60% relative humidity, both the building services and material selection are optimized for efficiency, sustainability, and durability.
the glazed façades are designed with warm-air curtain systems using floor convectors to prevent condensation. summer heat protection is achieved through the deep overhangs of the southern glazed façade and the highly insulated green roof. roof greenery with a thick humus layer absorbs and delays solar gain, contributing to thermal stability. evaporative cooling from soil moisture further enhances this effect.
all façades have external sun shading and, where necessary, internal glare protection.
a micro-perforated suspended membrane ceiling ensures optimal acoustics in combination with angled façade panels.