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Engineering services according to HOAI

Nine service phases. One point of contact.

The picture shows four employees of Zentrale Technik standing around a 3D model and discussing engineering services in accordance with HOAI © Filip Warchalowski/STRABAG

Engineering services from A to ZT!

Zentrale Technik (ZT) offers comprehensive engineering services in accordance with the German Fee Structure for Architects and Engineers (HOAI), accompanying you through all phases of your construction project - from the initial concept to final completion.

With its expertise in service phases 1-9, Zentrale Technik ensures efficient and successful design, execution and supervision.

All HOAI service phases from a single source

  • Preliminary study
    The picture shows two employees of the Zentrale Technik smiling as they look at a laptop and talk about the HOAI service phases. © Daniel Wanders/STRABAG

    The foundation for your construction project

    In service phase 1, we assess the project’s framework conditions, identify the client’s needs and analyse the initial project requirements.

    Our aim is to gather all relevant information in order to make an informed decision about the next design steps.
  • Preliminary design
    The picture shows five employees from Zentrale Technik exchanging ideas as part of service phases 1-9. © Daniel Wanders/STRABAG

    A well-thought-out planning concept

    The aim of service phase 2 is to develop the initial designs and conceptual ideas and to assess their feasibility.

    In doing so, we develop various solutions to meet the client's specified objectives and requirements.
  • Conceptual design
    An employee from Zentrale Technik department stands in front of a large screen with a plan of the service phases. © Filip Warchalowski/STRABAG

    From vision to precision

    From the initial preliminary design to the detailed design of the architecture, structure and engineering.

    In service phase 3, we concretize the entire design, create detailed drafts and determine the final concept.
  • Authorisation design
    The picture shows three employees from Zentrale Technik sitting in front of a laptop and discussing a service phase. © Daniel Wanders/STRABAG

    The path to a building permission

    In service phase 4, all necessary documents and supporting evidence are prepared for submission to the building authority in order to obtain permission for the construction project.

    Thanks to our network both within and outside the Group, we ensure a comprehensive foundation.
  • Execution design
    The picture shows two employees from Zentrale Technik talking to each other. © Filip Warchalowski/STRABAG

    Precise design, expert execution

    In service phase 5, we provide a comprehensive overview of the construction implementation and execution.

    We develop technical details, produce detailed plans and drawings and specify materials and techniques for the construction work.
  • Preparation for tendering
    The picture shows an employee of Zentrale Technik pointing at a large screen. © Daniel Wanders/STRABAG

    Setting the right course

    Through detailed and meticulous preparation of the tender process, we ensure that the selection process is both effective and transparent.

    Our objective for service phase 6: to ensure financial success, a collaborative partnership and a smooth project progression right from the start.
  • Assistance with tendering
    The picture shows two employees from Zentrale Technik shaking hands and smiling. © Daniel Wanders/STRABAG

    By your side, offering advice and support

    Are you looking for suitable partners and expertise for your construction project? We'll actively support you in your search!

    In service phase 7, we assist with the evaluation of tenders, conduct negotiations and ensure that all contractual and legal requirements are incorporated into the contracts.
  • Construction surveillance
    The picture shows two employees from Zentrale Technik in safety clothing on a construction site. © Daniel Wanders/STRABAG

    Stronger together – we roll up our sleeves and get stuck in

    After all, even the best design is useless if it doesn’t work out on site.

    In service phase 8, we ensure that the construction project is carried out professionally on the construction site and bring together the various contacts and contractors in an integrated manner.
  • Property management
    The picture shows two employees from Zentrale Technik in front of a green façade. © Daniel Wanders/STRABAG

    Everything under control - even after handover

    Whether maintenance, servicing or warranty support - in service phase 9, the final phase of our engineering services under the HOAI, we continue to look after your building even after completion.

    Benefit from our experience and let us manage your building efficiently and sustainably.

Engineering services according to HOAI: Your advantages

With us, your construction project is guaranteed to be a success! Put your trust in engineering services that go the extra mile. With our expertise across service phases 1–9, we are by your side from start to finish.

  • Comprehensive support: All HOAI service phases from a single source
  • Experience & expertise: you have over 1,300 experts at your side
  • Tailored solutions: Customized planning according to your requirements
  • Maximum reliability: Well-defined processes and seamless project coordination
  • Security: We are part of STRABAG and ZÜBLIN
  • A portrait of Niels Dürr, Member of the Board of Management at Zentrale Technik

    At Zentrale Technik, we approach construction projects across all project phases – with foresight and engineering expertise you can rely on. As part of STRABAG and ZÜBLIN, we create solutions that stand the test of time.

    Niels Dürr
    Head of Zentrale Technik

Engineering services according to HOAI - FAQ

  • What is the HOAI?

    The HOAI (German Schedule of Fees for Architects and Engineers) sets out how design and supervision services are structured and priced. It defines the so-called service phases, which are regarded as the smallest units for pricing. Each phase includes the basic services required for the proper fulfilment of a contract.

    In addition, there are special services that are listed in the HOAI but are not valued using the fee tables. For these, the fee is agreed on an individual basis.

    Since the 2021 reform, freedom of contract has applied: the table values of the HOAI serve as guidelines but are no longer binding. However, the HOAI remains a recognised set of rules for describing and structuring design services.

  • What are the HOAI service phases?

    The HOAI divides the project management process for building design into nine service phases. Each phase has a clearly defined scope of work:

    Service phase 1: Preliminary study
    Service phase 2: Preliminary design
    Service phase 3: Conceptual design
    Service phase 4: Authorisation design
    Service phase 5: Execution design
    Service phase 6: Preparation for tendering
    Service phase 7: Assistance with tendering
    Service phase 8: Building surveillance
    Service phase 9: Property management

    This structure ensures transparency and a clear division of tasks. Important: The percentage weighting of the phases depends on the scope of services. Depending on the scope of services, not only do the percentage shares differ, but in some cases also the content and number of service phases. All nine phases are relevant for building design, whereas fewer service phases are required for structural design and these are weighted differently.

    Are you looking to design a construction project and need professional support?
    Contact us for engineering services in accordance with HOAI – we will reliably guide you through all service phases 1–9.

  • How are fees calculated according to HOAI?

    Fees are based on the project’s chargeable costs and the service phases completed. Each phase contributes a specific percentage to the total fee. These percentages vary depending on the scope of services, for example between building design and technical installations.

    Basic services are assessed across the service phases. Special services are agreed separately. Since 2021, fees have been freely negotiable – the HOAI tables serve as a guide for calculating and determining fees.

You have a goal. We have the plan.

Whether it's a vision, project idea or specific construction project - we get your goals off the ground with engineering expertise and clear design. Together, we create well thought-out solutions that stand the test of time.

Find out more about Zentrale Technik