we do that
- With certainty

The Dupp Team
on the road on behalf of Justitia

The preparation of expert opinions is a particularly sensitive topic. Two argue and only one can be in the right. We provide facts for decision-makers.

All our colleagues are absolute experts when it comes to court opinions. We analyze the situation on site, quickly and professionally.

If necessary, we re-enact situations to reconstruct events as realistically as possible. We pay particular attention to the interfaces of a building in cases of structural damage or burglary: windows, doors and gates are routes that burglars take.



When an obejctive
opinion is required

Expert opinionS

  • Private expert opinion
  • Expert opinion
  • Arbitrator's report
  • Independent proceedings for the preservation of evidence
  • Insurance appraisals
  • Damage assessment / opinions
  • Assessment of the facts and the circumstances of the damage




What can you expect?


We check and assess all window and door systems as well as roller shutters for defects and damage. Whether assembly errors, construction errors or other damage.
We act and assess in compliance with legal requirements, such as CE marking, DIN standards and other directives as well as the general regulations in window and door construction, which play a central role.

If these requirements are not met, the component does not comply with the actual safety class or declared performance characteristic.

We analyze considering different aspects,
not individual fragments.

As a team of experts, we have an invaluable advantage in being able to examine and treat each case with a professional eye view from different angles.

We go into depth,
but we always focus on the big picture.

This way, nothing remains hidden from us. This ultimately led to a realistic expert opinion.

Which expert opinion variant do you need?

Private expert opinion

Private expert opinion

If the expert opinion is not commissioned by a court, it is always a private expert opinion.

“Private expert opinions submitted during the trial are substantiated party submissions that may not be disregarded when assessing other expert opinions, in particular those of the court. On the contrary, the judge is obliged to deal with them carefully.”

BGH, Urteil vom 17.10.2001 – IV. ZR. 205/00

Judicial report

Judicial report

In the case of court opinions, we as court-appointed experts as vicarious agents of the court.

Court opinions are expert opinions that can be used without restriction in a trial and cannot be challenged by the opposing party on the grounds of bias.

As court experts, we answer technical questions posed to us by the court, which are formulated in a so-called evidence order and form part of the case file. Our investigations and statements serve the judge to obtain comprehensive information about complex technical facts.

Arbitrator's Report

Arbitrator's Report

Within the framework of arbitrator's reports, we enable conflicts to be resolved out of court.

Disputing parties use arbitration experts (e.g. in the case of building damage or disputes in the context of construction) to avoid costly and protracted legal disputes. The parties involved agree to professional assessments by independent experts such as us. For example, with the help of arbitration assessments, disputes between builders and construction companies about technical issues and/or disagreements can be settled quickly and inexpensively.

Independent <br />evidence gathering procedure

evidence gathering procedure

The independent procedure of taking evidence of construction defects is a judicial procedure regulated in §§ 485 ZPO ff.

It concerns the determination of construction defects before, during or after the acceptance of construction (VOB). Prerequisites for the independent evidence procedure include the imminent loss of evidence, a judicial determination, the avoidance of litigation (settlement) or the suspension of limitation periods.

The independent evidence procedure is always applicable when time-consuming investigations would jeopardise the decision-making process.

Insurance appraisal

Insurance appraisal

In insurance appraisals, we deal with the following issues: establishing the damage and the cause of the damage, determining the residual value and calculating the costs of repairing the damage.

Insurance appraisals are commissioned by both insurance companies and policyholders.

Focal points of our expert opinions: Expert opinion and plausibility check of burglary, property and liability damage, damage assessment, damage evaluation, damage documentation, damage history analyses, determination of time and residual value.

Damage assessment/ Statements

Damage assessment/ Statements

Structural damage often occurs during the construction phase. In this case, we can document the current situation in an expert opinion by procedures for the preservation of evidence.

Even in the case of subsequently changed conditions, you receive evidence of existing defects that can be used in court. As certified experts, we document defects or structural damage from a purely technical perspective in the form of explanations of causes and declarations of responsibility. This can serve as a basis for legal action or to find suitable corrective measures. A well-founded damage analysis forms the basis for subsequent damage repair. If construction defects are suspected, it is particularly important to prepare an expert report at an early stage, as the investigation of the causes is usually more time-consuming in a later construction phase.






Because we love what we do, we are able to maintain the high quality standards for which we are known.

We have made it our habit to work precisely and meticulously. This is how we manage to pay attention to details and always ensure top quality in our expert opinions.  This is our drive and our motivation.


We love our profession.





Windows & Doors

Windows & Doors

Much more than just holes in the wall.

Rather, they are complex worlds that receive special attention.

Safety concepts

Safety concepts

Safety for life.
Security for you.

For a holistic view of individual circumstances.

Justice & Authorities

Justice & Authorities

For independent and neutral expert opinions!

Our offer for the judiciary, investigating authorities & public prosecutors' offices.



Complete service, also across trades.

Cooperation with an experienced team and highly competent partners.

Our certificates.
Your safety.

DIN EN ISO 16775:2015

DIN EN ISO 16775:2015

With the certification according to DIN EN ISO 16775:2015, the expert has obtained nationally, Europe-wide and internationally recognized certifications for the high level and topicality of his expert office.

The European Standard sets out the minimum requirements for expert services to be provided by individuals and/or associations of experts to their clients.

It demonstrated his proper work at a high level and showed that he actively completed regular checks and work tests.

Both the professional public and consumers will consider the following designation in the future: (ESP = Professional Service Provider). This means that the team of colleagues and experts around Alexander Dupp, which is already active throughout Europe, has a demanding proof of competence, a groundbreaking reliable indication of high-quality management, topicality, and independence.



The Europe-wide recognized certification of people based on DIN EN ISO/IEC 17024 is today one of the best criteria to be able to check the competence of an expert.

ISO/IEC 17024 allows for the qualifications and requirements of experts to be recognized and comparable worldwide. This is precisely why this certification is also gaining in importance in Germany. Due to its international recognition and importance, it is assumed in expert circles that this certification will also replace public appointment in a few years.

The international standard ISO/IEC 17024 is valid worldwide. In 2003, it was adopted as a European standard (EN ISO/IEC 17024) and shortly thereafter also established as a German standard (DIN EN ISO/IEC 17024). An expert who has been certified by a certification body accredited according to DIN EN ISO/IEC 17024 thus enjoys international recognition of his competence.




Continuous development and review

According to the requirements of ISO/IEC 17024, the certified experts must continuously expand and update their expertise. In addition, expert reports and other evidence must usually be submitted to the certification body. Clients and courts can therefore assume that an expert certified based on ISO/IEC 17024 also has sound and up-to-date knowledge and corresponding practical experience as an expert.


OF Interest for
Justice & Authorities


Windows, doors and roller shutters—as a team of experts with a shared knowledge base and valuable diverse experience and expertise, we are well-prepared for these highly sensitive building interfaces.

We evaluate and inspect all door and window systems as well as roller shutters for possible defects and damage: whether assembly or construction errors or damage of any kind. Compliance with laws and general regulations in window and door construction always plays a central role. It is a science in itself: we have analytical perspectives in every respect – we look at the whole issue, not just the symptoms.

As a team of experts, we can look at and deal with individual cases from different angles with a professional eye. Often the devil is in the detail. We go into depth, but always focus on the big picture.

Especially when it comes to forensic matters, you have come to the right place because everyone in our team of colleagues is an absolutely competent contact for court reporting.

All members of our team can arrange on-site appointments and prepare expert reports: quickly and professionally, as the Dupp team expects.





Interesting for
Public prosecutors & investigating authorities


As experts on windows and doors, we have been working with investigating authorities and public prosecutors for many years. If you want to read your opponent'face, you have to put yourself in their shoes. An old saying.

Figuratively speaking, we put ourselves in the gloves of the perpetrator for you. Our Technical Development and Performance Center (TELZ) with its professional special equipment offers the perfect conditions for the exact re-enactment of burglary situations. Thanks to the latest technology and absolutely reliable expertise, we can precisely reproduce and analyze the course of events. To be able to re-enact the course of events and to create reliable trace images, detailed expert knowledge of the corresponding construction of windows and doors is indispensable.

Therefore, we investigate vividly and in a practical procedure how the perpetrators probably proceeded using which means. Investigating authorities such as the police and the public prosecutor's office have already made use of our special reconstruction technique on several occasions.

Alexander Dupp & Colleges is your reliable partner when it comes to whether a burglary offense or insurance fraud has actually occurred. Based on many years of experience and sound expertise, we thus help you to get wise to the perpetrators.

Our well-coordinated team of trained experts, our many years of experience, our know-how and, finally, our highly efficient quality assurance guarantee a fast and precise processing time and thus a quick preparation of an expert opinion. We also maintain constant contact with leading laboratories, and our certifications speak for themselves.

Reliable expert opinions are a matter of absolute trust. Therefore, on the following pages you will find basic information about our team of specialists as well as our range of services.

Would you like to learn more about our services for investigating authorities and public prosecutors? Get in touch with us!





Why not get in touch with us right now!



Alexander Dupp & Kollegen
Bornstraße 13
56412 Girod

T: 0 64 85 / 18 03 31
F: 0 64 85 / 18 06 76



© 2023 Alexander Dupp - all rights reserved.

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