Austrian OGH on Liability for Providing Incorrect Expert Opinions

Feb 26, 2026 Benn-Ibler Rechtsanwälte

The Austrian Supreme Court (Oberster Gerichtshof, hereinafter OGH) has recently ruled on a claim for damages against an expert in a construction case.

The claimant commenced a construction project in early 2017 pursuant to an approved building permit. However, following a prohibition issued in November 2018 due to non-compliance with the permit’s terms, the claimant subsequently applied for approval of the proposed modifications to the project.

Expert miscalculation of usable floor space density

In the course of the ensuing administrative proceedings, the building authority appointed the defendant as a non-official expert in December 2018. The defendant was tasked with verifying whether the maximum allowable usable floor space density of 0.40, as specified in the development plan, would continue to be observed after the proposed modifications.

According to his expert assessment, the defendant determined that the usable floor space density was 0.5066. Subsequently, the plaintiff commissioned two independent expert evaluations, and the building authority enlisted the opinions of two further specialists. Two of these expert reports concluded that the usable floor space density was below 0.40.

In December 2022, the plaintiff received approval for the requested modifications during the second round of proceedings, provided that the usable floor space density remained at 0.40.

The plaintiff pursued compensation from the defendant as a result of the significant delay experienced during the approval process.

Consequently, the lower courts dismissed the claim. However, the court of appeal found that the damages claimed by the plaintiff could not be attributed to the alleged errors in the expert opinion.

Plaintiff failed to meet burden of proof

OGH case law states that if an expert gives a mistaken opinion during a civil trial, they are responsible for any harm it causes to the parties involved. This rule also applies to independent experts who aren't officially appointed.

Generally, anyone seeking compensation due to an inaccurate expert opinion must prove both the damage sustained and the causal connection between the misconduct and the damage.

In conclusion, the plaintiff failed to establish that the purported damages resulted from the alleged inaccuracies in the defendant'’ expert opinion; accordingly, the defendant was not liable.

OGH, 3 Ob 165/25y, 17 December 2025