4a Architekten

The Main Bad in Frankfurt-Bornheim impresses with its compact architecture, well-thought-out functionality, and atmospheric design – all while operating in a resource-efficient and economical manner.

Acting as general planners, 4a Architekten have developed in close proximity to the ice rink a three-storey building that fits compactly into the existing urban structure and makes efficient use of the available space. The new Main Bad offers around 900 square metres of water space for leisure, sport and recreation. The design is characterized by a clear, minimalist design language. Sinuous curves and a recess in the façade in the entrance area lend dynamism to the basic triangular form. The interior is dominated by tiles, plastered surfaces, and acoustically effective surfaces, which not only have a calming effect in terms of design, but are also particularly easy to clean and maintain. The colour concept relies on strong shades of blue, green and yellow to create a lively atmosphere. The façade has a differentiated appearance: The plant-covered base storey is followed by a perforated aluminium shaft with coloured metal slats and glazed elements. Here too, a calm and structured material and colour concept dominates.

The recreational bathing hall offers numerous attractions: an adventure pool with a water mushroom and hot whirlpool as well as a toddlers' area, the numerous attractions of which invite children to play. Additional bathing fun is provided with a wide wave slide and – with an eye to energy efficiency – an entirely indoor tube slide. The sports bathing hall has a 25-metre pool with six lanes, one-metre and three-metre diving boards, and a partially variable depth that can be set by means of a lifting floor. The offering is rounded off by a separate learners’ pool with wide access steps. The upper floor comprises a spacious sauna area with five different saunas. A green atrium provides a natural atmosphere, daylight, and a high quality of stay. Relaxation and fireplace areas, a catering area, and an outdoor area with a plunge pool, cold showers, and a sun terrace enrich the facilities. The attic also houses another relaxation room with a view of the surrounding area.

Sustainability as a principle
A basement was not added to Main Bad because of the difficult ground conditions – a rather unusual approach both in terms of design and of functionality: the technical rooms are located on the ground floor while the swimming hall with its generous glazing is located on the first floor. This location offers bathers an unimpeded view of the countryside and ensures a light-flooded bathing experience with panoramic qualities.

The Main Bad is impressive not only architecturally, but also ecologically. The compact, three-story cubature contributes to the building's energy efficiency, as it reduces the building envelope in relation to the volume, thereby minimizing heat loss. Openings and facade surfaces are optimized for daylight utilization, energy efficiency, and thermal performance. Skylights allow natural light to penetrate deep into the building, improving the quality of the environment and reducing the need for artificial lighting; at the same time, they enable passive solar energy gains.

A comprehensive energy concept ensures resource-saving and economical operation. 450 photovoltaic modules on the roof generate up to 150,000 kWh of electricity annually. This is supplemented by a modern combined heat and power plant, systems for heat recovery from ventilation and bathing water technology, and the possibility of using waste heat from the neighboring ice rink – the necessary technical preparations have been implemented. To reduce the consumption of fresh water, rainwater that has been collected is used for cleaning and watering the outdoor facilities. An integrated rainwater retention system also protects the public sewer network in the event of heavy rainfall. Lighting is provided almost exclusively by energy-efficient LEDs, which minimise maintenance intervals and guarantee a long service life.