About Us

Get to know us

Meet our motivated and professional experts who are responsible for planning and implementing your projects, learn more about the history and development of OK ZT-GmbH and gain an overview of our certified quality management system, which forms the basis for our work.

– Management – Our story – Quality Management – Experts

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Dipl. Ing. Joachim Kantz

Managing Director

Mobile +43 664 80 944 410 j.kantz@okzt.at

Curriculum Vitae

Mr. DI Joachim Kantz graduated from the Graz University of Technology in the Department of Civil Engineering. During and after his studies he worked for the civil engineering offices Trauntschnig and Unterreiter on civil engineering projects and participated in the areas of ÖBA, accompanying control and PM. In 1994, he joined the office of Dipl.-Ing. Heinrich Oberressl as project and office manager. In 1998, after successfully passing the civil engineering examination, he became partner and managing director of Oberressl & Partner ZT-Ges.m.b.H. In 2000, he was included in the list of experts of the Klagenfurt District Court. His main activities include project management for building construction, commercial and industrial facilities and municipal infrastructure. Since 2008, Mr. Kantz is registered at the Slovenian Chamber of Engineers.

Baurat Dipl. Ing. Heinrich Oberressl

Company Founder

† 24. September 2021

Curriculum Vitae

Our mastermind and founding father, Mr DI Baurat h.c. Heinrich Oberressl, was born in 1936 in the beautiful Gailtal. In his apprenticeship years as a bricklayer, he quickly became a successful independent master builder and only as a late professional, he went to study at the Graz University of Technology. After his studies he changed to the planning division in 1986, and has been working as a civil engineer and a court-certified expert since then. The most important thing that Heini taught us during his years of being actively involved in the company is that, in addition to organisation and specialist knowledge, more important attributes are required of a civil engineer. These attributes are, and they also describe him and his personality, cordiality, modesty and a lot of heart and brain.

Dipl. Ing. Wolfgang Obernosterer

Partner & Shareholder

Mobile +43 664 80 944 415 w.obernosterer@okzt.at

Curriculum Vitae

Mr. DI Wolfgang Obernosterer graduated from Graz University of Technology in the field of industrial engineering. During his studies, he gained first professional experience in the office of the Carinthian provincial government as well as in the civil engineering office Schnattler. After successfully completing his studies, he joined OBERRESSL & KANTZ ZT-GmbH in 2000, as a project manager of the department of hydraulic and urban engineering. His activities are mainly focused on project management in the field of water supply and sanitation. This includes planning, submission, tendering, the handling of subsidies, as well as local construction supervision. In addition, Mr. Obernosterer also manages projects in the field of structural engineering and road construction. Since 2011, Mr. DI Wolfgang Obernosterer has been an authorized representative of OBERRESSL & KANTZ ZT-GmbH.

Our Story

The foundation for our office as we know it today was laid in 1986 by Heinrich Oberressl. After two decades as a successful master builder, he decided to adjust his professional path and focused on civil engineering. In 1994, Joachim Kantz joined the company as project manager, whereupon Oberressl & Partner ZT GmbH was jointly founded in 1998. From 2002 to 2004, the first expansion steps towards Slovenia and Croatia were taken. In 2002, the office moved from Völkermarkter Strasse to Feldkirchner Strasse. Since 2008, the office has been located at its current location, Schleppe Platz. In the first years we were mainly known for structural engineering, competences in the fields of building construction and urban water engineering were successively built up.

With the arrival of Wolfgang Obernosterer in 2011, the three pillars of the company were also made visible to the outside world. In the following years, our branch network was expanded with offices in Eberndorf (2015), Ljubljana (2015), Pula and Vienna (2018). Our international orientation is also legally secured by the official approvals in our main markets Slovenia (since 2009), Croatia (since 2018) and the Czech Republic (since 2014), as this means that we are entitled to present to the relevant authorities in these countries. Since 2018, we have been taking our first steps across the Atlantic and into Asia.

Quality Management & Philosophy

Our top priorities are high quality, timeliness and cost awareness. The high quality standard that our customers expect from us, we also demand from ourselves. In order to guarantee this high standard in the long term, we rely on continuous training and further education of our employees, as well as a dynamic development of our office processes, always adapted to the current focus and the respective task. Our certified quality management system ensures that we optimize organizational and planning processes in our daily work. This enables us to continuously improve our internal processes and products.