Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker. Ingenieurbüro für Bauphysik

What Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker. Ingenieurbüro für Bauphysik does

Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker. is a Berlin-based building-physics (Bauphysik) engineering firm founded in 1986 by Prof. Dipl.-Ing. Axel C. Rahn. The firm operates as a GmbH under founder-led private ownership with a team of approximately 25–30 employees, including multiple publicly appointed and sworn expert witnesses (ö.b.u.v. Sachverst\u00e4ndige) and officially recognized testing experts for energetic building planning. Its service portfolio spans six core areas: (1) thermal and hygric building physics, including energy-efficient building planning, heat/moisture protection, building and component simulation, and waterproofing; (2) sustainable building certification coordination (BNB, DGNB, QNG, LEED); (3) building damage analysis, condition surveys, renovation concepts, and quality control; (4) expert witness services covering private opinions, arbitration opinions, evidence documentation, and court opinions for courts in Berlin, Brandenburg, Hamburg, Oldenburg, Chemnitz, and Stuttgart; (5) building and room acoustics including sound insulation and immission protection; and (6) physical measurements performed under dual accreditation as a VMPA-Güteprüfstelle nach DIN 4109 and a DAkkS-accredited measurement laboratory under § 26 BImSchG.

The firm's revenue model is professional services: project-based consulting and testing engagements scoped and priced per project, with no public pricing or subscription/SaaS component. Customer acquisition is primarily direct engagement and referrals, supplemented by court appointments and public procurement for government and institutional clients. The client base spans federal ministries, federal agencies, cultural-heritage institutions (including UNESCO World Heritage sites on Berlin's Museumsinsel and Prussian palaces), large enterprises (Deutsche Bank, Coca-Cola HQ, Steigenberger, Zoofenster), healthcare and research institutions (Vivantes, Max-Planck, NCAOR Antarctic station), and industrial clients. Geographic reach is concentrated in Germany (primarily Berlin and Brandenburg) with selected international commissions in Italy, Austria, France, and Antarctica.

The firm is quality-certified under DIN EN ISO 9001 and registered as a vocational training institution with IHK Berlin. Its go-to-market leverages a reference-project portfolio, a leadership presence in industry bodies (Baukammer Berlin, FLiB, BVS, WTA, BuFAS), university teaching at FH Potsdam, and a recently launched Spotify podcast. No external funding, M&A activity, or parent-company ownership is disclosed.

Name

Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker. Ingenieurbüro für Bauphysik

Legal name

Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker.

Website

https://ib-rahn.de

Company type

Private

Founded year

1986

Operating status

Operating

Headcount range

11–50 employees

Short description

Ingenieurbüro Axel C. Rahn GmbH is a Berlin-based building-physics engineering firm with ~25–30 employees, providing thermal/moisture consulting, acoustics, building damage analysis, and court-recognized expert witness services, operating a VMPA-certified and DAkkS-accredited testing laboratory. It serves federal ministries, UNESCO heritage sites, and large enterprises across Germany and selected international projects.

Ownership category

akta.pro rank

Product category

Building Physics Engineering Consulting

NAICS

Engineering Services (541330), Management, Scientific, and Technical Consulting Services (5416)

SIC

Services-Engineering Services (8711), Services-Testing Laboratories (8734)

akta.pro primary industry

Civil & Structural Engineering Consulting (BPAHAIAA)

Keywords

• Building physics engineering
• Acoustic consulting services
• Energy efficiency consulting
• Building damage analysis
• Expert witness services

Headquarters

HQ city

Berlin

HQ country

Germany

HQ region

Europe

Offices1 record

Markets served

GTM type

B2B

Offering type

Services

Cost components

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

Revenue model

1. Engineering and Consulting Services: Project-based professional engineering and consulting services in building physics, including thermal physics, moisture protection, building acoustics, room acoustics, building damage analysis, expert witness reports, and sustainable building certification. Revenue generated through individual consulting engagements for private and public clients.
2. Expert Witness and Court Testimony: Expert witness services including private expert reports, arbitration reports, evidence documentation, and court-appointed expert testimony for building disputes and legal proceedings.
3. Testing and Measurement Services: Physical testing services including acoustic measurements, airtightness testing (Blower-Door), moisture measurements, climate measurements, and immission measurements. Performed as a DAkkS-accredited and VMPA-certified testing laboratory.

Go-to-market motion2 records

Distribution channels3 records

Marketing channels4 records

Core offering

The company provides professional engineering consulting services in building physics (Bauphysik). Its work covers thermal and moisture protection, building and room acoustics, energy-efficient and sustainable building planning, building damage analysis, and expert witness (Sachverständigen) services supported by an in-house certified measurement laboratory.

Product overview

Ingenieurbüro Axel C. Rahn GmbH is a building physics (Bauphysik) engineering firm offering a comprehensive portfolio of professional consulting services rather than a software product. The firm's service ecosystem is organized into six core areas: (1) Bauphysik covering thermal/hygroscopic consulting, energy-efficient building planning, building and component simulation, and waterproofing; (2) Nachhaltiges Bauen for sustainable building certification coordination (BNB, DGNB, QNG); (3) Bauschadensanalyse encompassing building condition analysis, renovation concepts, planning implementation, and quality control; (4) Sachverständigenwesen providing expert witness services including private, arbitration, and court opinions plus evidence documentation; (5) Bau- und Raumakustik covering building acoustics, room acoustics, sound immission protection, and acoustic measurements; and (6) Messungen including climate/temperature measurements, moisture measurements, Blower-Door testing, and acoustic quality testing. The firm operates two certified laboratories—a VMPA-certified quality testing station per DIN 4109 and a DAkkS-accredited measurement laboratory for immission protection. The company serves diverse project categories including residential, office, cultural/monuments, laboratory/healthcare, hotel/commercial, and school/sports facilities across Germany.

Differentiator

Problem solved

Functional benefit

Products and services

• Building Physics (Bauphysik) Consulting Core engineering consulting covering thermal protection, moisture protection (Wärme- und Feuchteschutz), energy-efficient building planning, and building/component simulation for architects, developers, and public clients.
• Building and Room Acoustics (Bau- und Raumakustik) Acoustic consulting including room acoustics, building acoustics, and certified acoustic measurements delivered to construction and renovation projects.
• Sustainable Building Consulting (Nachhaltiges Bauen) Advisory on sustainable construction practices, energy performance, and certification-relevant building physics for new builds and retrofits.
• Building Damage Analysis (Bauschadensanalyse) Forensic analysis of building defects and damage, including root-cause investigation and remediation recommendations, used by owners, insurers, and legal clients.
• Expert Witness Services (Sachverständigenwesen) Provision of publicly appointed or court-recognized expert opinions and testimony in construction, acoustic, and building-physics disputes.
• Physical Measurements (Messungen) On-site and laboratory-based building physics measurements (acoustic, immission, and diagnostic testing) conducted in certified laboratories.

Quantifiable outcome

• More than 30 years of continuous operation as a specialized building physics firm with a team exceeding 30 employees.
• +2 more outcomes

Named customers15 records

Segments5 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Integration4 records

Feature4 records

Partnerships

Six partnerships are on record, tiered core and minor.

• Bundesamt für Bauwesen und Raumordnung (BBR)coreStrategic or Co-development PartnerFederal government agency that commissions the firm for building physics consulting on significant federal construction projects including museums on Museumsinsel and other cultural heritage buildings.
• Industrie- und Handelskammer zu Berlin (IHK Berlin)minorStrategic or Co-development PartnerProfessional oversight body for expert witness activities; also registers the firm as a vocational training institution.
• Baukammer BerlinminorStrategic or Co-development PartnerProfessional chamber of the construction industry; provides oversight for testing experts and hosts firm leadership in vice president and committee positions.
• Stiftung Preußische Schlösser und Gärten Berlin-BrandenburgcoreStrategic or Co-development PartnerFoundation responsible for Prussian palaces and gardens; commissioned detailed renovation concepts and building physics consulting for buildings including Neues Palais in Sanssouci Park.
• FLiB – Fachverband Luftdichtheit im Bauwesen e.V.minorStrategic or Co-development PartnerProfessional association for building airtightness; firm members hold leadership positions and contribute to industry standards development.
• WTA – Wissenschaftlich-Technische Arbeitsgemeinschaft für Bauwerkserhaltung und Denkmalpflege GmbHminorStrategic or Co-development PartnerScientific-technical association for building preservation and monument conservation; firm contributes expertise in building physics for heritage building preservation.

Scale indicators3 records

Recent moves5 records

Expansion highlights4 records

Direct peers

• Kurz und Fischer GmbH: Specialized German engineering firm focused on building physics (Wärmeschutz, Feuchteschutz, Schallschutz) with comparable DIN 4109 testing and acoustic consulting offerings. Strong direct overlap in core Bauphysik service lines.
• Peutz Consult GmbH: Dutch-German engineering consultancy offering building physics, acoustics, and sustainability consulting. Comparable service portfolio with international project reach and similar focus on heritage and complex building projects.
• Graner + Partner Ingenieure GmbH: Bergisch Gladbach-based engineering firm offering building physics, acoustics, and energy consulting with similar reference portfolio depth in German commercial and public-sector projects.
• ITA – Ingenieurgesellschaft für Technische Akustik mbH: Essen-based engineering firm specializing in technical acoustics, building acoustics, and room acoustics. Direct competitor in building and room acoustics consulting with comparable measurement capabilities.
• LairmConsult GmbH: Hamburg-based specialist in acoustic immission protection and building physics. Directly competes on noise immission measurements and acoustic expert opinions, with similar DAkkS-style accredited testing operations.
• Müller-BBM GmbH: One of Germany's largest independent engineering consultancies for acoustics, building physics, and immission protection. Directly comparable in core building acoustics and immission measurement services, though at substantially larger scale and broader geographic footprint.
• IBN Bauphysik GmbH: Specialized building physics consultancy offering energy consulting, sound insulation, and damage analysis. Closely aligned with Rahn's thermal physics, moisture protection, and energy efficiency service lines.
• ITAe – Ingenieurbüro für Technische Akustik und Bauphysik: Specialist consultancy combining building acoustics and building physics with measurement services. Comparable mid-sized niche positioning with VMPA/DAkkS-style accredited testing operations.

Broad incumbents

• TÜV Rheinland (Building Physics / Acoustics Services): Large international testing and certification body offering building acoustics testing, energy certification, and immission measurements as part of a broad testing portfolio. Competes in measurement services and certification work but not as a specialist consultant.

Regional players

• HHP Berlin Beratende Ingenieure GmbH: Berlin-based engineering consultancy with overlap in fire protection, structural, and building physics consulting. Geographic overlap in the Berlin/Brandenburg market makes it a regional peer.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat4 records

Key risks6 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/ingenieurb%C3%BCro-axel-c-rahn-gmbh-die-bauphysiker-ingenieurb%C3%BCro-f%C3%BCr-bauphysik

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

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 Ingenieurbüro Axel C. Rahn GmbH Die Bauphysiker. Ingenieurbüro für Bauphysik