What 4a Architects Stuttgart does

4a Architekten GmbH is a Stuttgart-headquartered, privately held German architecture firm (GmbH) that specializes exclusively in the design of public baths, swimming pools, thermal spas, and sauna landscapes. Founded by four managing directors — Matthias Burkart, Andreas Ditschuneit, Martin Reimer, and Ernst Ulrich Tillmanns — the firm operates with a single headquarters at Hallstraße 25, 70376 Stuttgart, and maintains exhibition and conference presence in Berlin and Cologne. Its client base consists almost entirely of German municipal governments and public utilities (Stadtwerke, Bäderbetriebe, Magistralverwaltungen), plus one project in Luxembourg, with projects acquired through public procurement processes and architectural design competitions.

The firm's service offering spans competition design, full architectural planning, BIM-based design coordination, and project oversight for new construction, renovation, and extension of bath facilities. Notable completed projects include Hallenbad Neutraubling (5,700 m², opened Dec 2024), Mineralbad Berg Stuttgart (renovation of a 163-year-old bath), Salinarium Therme Bad Dürkheim (7,957 m² expansion opened Nov 2025), Hirschbachbad Aalen (11,515 m², opened 2025), Main Bad Bornheim Frankfurt, Emser Thermenhotel, and Syrdall Schwemm Luxembourg. The firm has pioneered a modular timber construction system for dismantlable indoor swimming pools (Aquabox/Modulbad Stuttgart), developed with partners Blumer Lehmann and POOL out of the BOX, selected as one of 37 official IBA'27 projects, enabling relocation of pools across city districts.

Revenue is generated through professional architectural services fees on publicly procured and competition-based commissions, with project durations typically spanning multiple years from competition through construction completion. Pricing is not publicly disclosed and varies by project scale and complexity (fee ranges from small competition entries to multi-million-EUR public works). The firm has won consecutive international awards (BIG SEE 2024/2025/2026, Iconic Awards 2021/2022/2025, Architizer A+ Award 2026, Staatspreis Baukultur Baden-Württemberg 2024) and presents at industry events including aquanale Cologne, AEDES Architecture Forum Berlin, and the IAKS Nordic Sports Summit, demonstrating thought leadership in the German public-bath architecture segment.

Name

4a Architects Stuttgart

Legal name

4a Architekten GmbH

Website

https://4a-architekten.de

Company type

Private

Founded year

1990

Operating status

Operating

Headcount range

11–50 employees

Short description

4a Architekten GmbH is a privately held Stuttgart-based architecture firm specializing in public bath, swimming pool, and thermal spa design for German municipal governments and public utilities, with projects acquired through public procurement and architectural competitions.

Ownership category

akta.pro rank

Headquarters

HQ city

Stuttgart

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Marketing or Sales, Technology or R&D, Infrastructure

Revenue model

1. Architectural Design and Planning Services: Revenue generated through architectural planning, design, and project management services for bath and swimming pool construction projects. Projects are commissioned by municipal governments and public utilities through competitive procurement processes.

Go-to-market motion1 record

Distribution channels1 record

Marketing channels5 records

Core offering

4a Architekten provides specialized architectural planning, design, and project management services for public bath, swimming pool, and thermal spa facilities. Engagements span new construction, renovation of historic bath architecture, and innovative modular timber pool construction, contracted primarily through public procurement and architectural competitions. Clients are municipal governments and public utilities in Germany and Luxembourg, with a portfolio of 20+ completed projects including municipal indoor pools, thermal spas, sauna facilities, and hotel-spa developments.

Product overview

4a Architekten is a Stuttgart-based architecture firm specializing in public swimming pool and bath architecture. Their portfolio encompasses new construction and renovation of indoor/outdoor pools, thermal spas, sauna facilities, and hotel-spa developments. Key projects include award-winning swimming pools (Hallenbad Neutraubling, Mineralbad Berg Stuttgart), thermal spas (Salinarium Bad Dürkheim), modular timber construction pools (Aquabox Stuttgart as IBA'27 project), and leisure pool complexes (Hirschbachbad Aalen, Main Bad Bornheim). The firm also undertakes competition projects, renovations, and sustainable bath architecture using timber-hybrid and modular construction methods. Their work spans Germany, Luxembourg, and Austria, with a focus on combining functional excellence, atmospheric design, and sustainable construction principles.

Differentiator

Problem solved

Functional benefit

Products and services

• Hallenbad Neutraubling New construction of a municipal indoor aquatic centre for leisure and school sport, delivered for Stadt Neutraubling. Includes a 25-meter, six-lane pool with diving tower, family leisure area with massage jets and bubble loungers, a textile bio-sauna, and a steam bath; winner of BIG SEE Architecture Award 2025 and ICONIC AWARDS 2025 Innovative Architecture.
• Mineralbad Berg Stuttgart Renovation and architectural redesign of Stuttgart's 163-year-old mineral bath for Bäderbetriebe Stuttgart, preserving the historical character while adding a contemporary L-shaped building with a lake-character outdoor pool and gallery extensions. Recognition: Staatspreis Baukultur Baden-Württemberg 2024, Deutscher Architekturpreis 2021 shortlist, ICONIC AWARDS 2021 winner, Heinze ArchitektenAward 2021 shortlist.
• Salinarium Therme Bad Dürkheim Extension of the existing Salinarium leisure pool for Stadtwerke Bad Dürkheim GmbH, adding a thermal spa and sauna area with curved forms across three levels, including a thermal indoor pool, outdoor warm pools, steam baths, panorama sauna, and brine relaxation room with a mini graduation tower; features a wine-inspired golden facade referencing the local Riesling tradition.
• Syrdall Schwemm Niederanven School and recreational bath facility in Niederanven, Luxembourg for C.N.I. Syrdall Schwemm, with a compact, dynamic structural form, large-surface glazing, fluid indoor-outdoor transition, and a golden exterior facade referencing the local property designation.
• Emser Thermenhotel Four-star thermal hotel with 84 double rooms, seminar rooms, restaurant, and rooftop SkyLounge on the Lahn river bank, for Emser Therme GmbH; connected to Emser Therme via a glass skywalk, with rounded forms inspired by river pebbles, flowing interiors with muted colors, and abundant wood.
• Hirschbachbad Aalen Leisure pool complex for Stadt Aalen with indoor and outdoor areas on a hillside setting, integrating landscape, architecture, and function; includes a competition-standard pool, family and leisure area, sauna area, and outdoor pool, with terraced architecture and integrated sustainability systems.
• Modulbad Stuttgart (Aquabox) Europe's first modular and dismantlable indoor swimming pool in timber modular construction, designed for temporary deployment and relocation between Stuttgart city districts (Zuffenhausen, Möhringen, Untertürkheim); built to a 'designed for disassembly — built to last' Cradle-to-Cradle standard with high prefabrication degree and reduced CO2 footprint; developed in partnership with POOL out of the BOX GmbH and Blumer Lehmann GmbH; accepted as an IBA'27 StadtRegion Stuttgart network project.
• Main Bad Bornheim Frankfurt Family swimming pool for Stadt Frankfurt am Main replacing the Panoramabad with approximately 900 m² of water area, including adventure pools, slides, a 25-meter sports pool with a diving platform, a training pool, and a large sauna area with four themed saunas; designed as an energy-efficient building using photovoltaic systems, heat recovery, and rainwater harvesting.
• Kombibau Kall (Turnhalle und Hallenbad) Combined gymnasium and indoor swimming pool replacement for Gemeinde Kall, built following the 2021 flood damage; combines a single-court gymnasium with a 25-meter indoor pool in a compact, sustainable building using prefabrication and modular construction methods.
• Stadtbad Weißenfels New construction of a city bath in Weißenfels for Stadt Weißenfels, delivered in working group (Arbeitsgemeinschaft) with Thoma Architekten Berlin as ARGE I WEI, Leipzig; two-story building with basement divided into three functional areas: foyer and swimming hall with spectator gallery, second bath hall with leisure and children's area, and a separate sauna landscape.
• RappSoDie Bad Rappenau New spa, sports, and family pool in Bad Rappenau based on a comprehensive sustainable design concept using a timber-hybrid construction system; integrates the existing sauna area into a new overall concept, applying N!BBW criteria of Baden-Württemberg for energy efficiency and recyclability.

Quantifiable outcome

• Hallenbad Neutraubling: 5,700 m² gross floor area, 30,700 m³ volume, completed December 2024
• +3 more outcomes

Named customers10 records

Segments1 record

Ideal customer profiles1 record

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature2 records

Partnerships

14 partnerships are on record, tiered core and supporting.

• Thoma Architekten, BerlincoreStrategic or Co-development Partner · 20 April 2026Partnership in Arbeitsgemeinschaft (ARGE) for Stadtbad Weißenfels project. Together forming ARGE I WEI, Leipzig for the new city bath construction.
• POOL out of the BOX GmbHcoreStrategic or Co-development Partner · 3 November 2025Developer and general contractor for modular and serial indoor swimming pool construction. Partnership for the mobile indoor swimming pool project in Stuttgart-Zuffenhausen, developed as Europe's first dismantlable indoor swimming pool with modular timber design.
• Blumer Lehmann GmbHcoreTechnology or IntegrationTimber construction company providing engineering and modular timber construction for the mobile indoor swimming pool projects.
• Kannewischer Ingenieurgesellschaft mbHsupportingTechnology or IntegrationBuilding services engineering partner for swimming pool projects including modular construction projects.
• Wassertechnik WertheimsupportingTechnology or IntegrationWater technology partner providing technical systems for swimming pool construction projects.
• ZELLER Bäderbau GmbHsupportingTechnology or IntegrationStainless steel pool construction partner for swimming pool projects including modular construction.
• Prokopetz Architekten + Ingenieure GmbHsupportingTechnology or IntegrationConstruction management partner for Hallenbad Neutraubling project.
• Licht Kunst LichtsupportingTechnology or IntegrationLighting design partner for Emser Thermenhotel project. Won German Lighting Design Award 2025 for the project's lighting design.
• Planstatt Senner, ÜberlingensupportingTechnology or IntegrationLandscape planning partner for competition projects including Saarburg leisure pool and Spickelbad Augsburg.
• schlaich bergermann partner, StuttgartsupportingTechnology or IntegrationStructural engineering partner for competition projects including Saarburg leisure pool and Spickelbad Augsburg.
• IGP Ingenieurgesellschaft, PforzheimsupportingTechnology or IntegrationEngineering partner for Spickelbad Augsburg competition project.
• Luces Ingenieure, PulheimsupportingTechnology or IntegrationBuilding services engineering partner for Saarburg leisure pool competition.
• Zirkularis, StuttgartsupportingTechnology or IntegrationSustainability strategies partner for Saarburg leisure pool competition.
• IBA'27 - Internationale Bauausstellung 2027 StadtRegion StuttgartcoreStrategic or Co-development PartnerPartnership for mobile indoor swimming pool project (Aquabox) accepted as one of 37 official IBA'27 projects. The International Building Exhibition promotes innovative and sustainable construction approaches.

Scale indicators3 records

Recent moves6 records

Expansion highlights5 records

Broad incumbents

• Hascher Jehle Architektur: Berlin-based German architecture firm with deep public-sector and sports/stadium portfolio. Competes with 4a in national architectural competitions for public infrastructure, including leisure and recreation facilities.
• Sauerbruch Hutton: Berlin-based award-winning German architecture firm with public-cultural-building portfolio. Comparable in profile and international award recognition, and a likely competitor for signature public commissions in Germany.
• Auer Weber: Munich-based German architecture firm with strong sustainability and public-building portfolio. Competes with 4a in the same German public-architect competition space and shares a DGNB-aligned sustainability positioning.
• Kadawittfeldarchitektur: Aachen-based German architecture firm with strong public-sector practice and recognized expertise in sustainable, energy-efficient building design. Competes with 4a for high-end public commissions across Germany.
• HPP Architekten: Düsseldorf-headquartered, one of Germany's largest architecture practices with broad portfolio including leisure, hospitality, and public projects. Competes with 4a in large public tenders and brings deeper institutional scale to similar project types.
• Behnisch Architekten: Stuttgart-headquartered architecture firm with comparable scale and German public-sector portfolio across education and leisure. Overlaps with 4a on sport/recreation architecture and competes for similar VgV commissions in Baden-Württemberg.
• Bez+Kock Architekten: Stuttgart-region German architecture practice with public-sector and building-renovation expertise. Comparable in size and regional footprint to 4a, and a realistic competitor in Baden-Württemberg public tenders.

Others

• Kannewischer Ingenieurgesellschaft: German engineering consultancy specializing in building services, energy, and pool-water technology. Existing subcontracting partner to 4a on swimming-pool projects; provides specialist services that complement rather than compete with architectural scope.
• POOL out of the BOX GmbH: General contractor for modular and serial indoor swimming pool construction, co-developer of the Stuttgart Aquabox modular project with 4a. Functions as 4a's construction-side delivery partner rather than architectural competitor.

Direct peers

• Barr + Wray: UK-based specialist consultancy focused on pool, spa, water feature and leisure facility design. Closest international peer in terms of pure bath-architecture specialization and would compete for European leisure-water commissions.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

• Facebookfacebook.com/4aArchitektenStuttgart
• LinkedInlinkedin.com/company/4a-architekten-gmbh

Revenue estimate

Valuation estimate

Number of profiles

Profiles4 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about 4a Architects Stuttgart