Common errors in a construction expert report (and how they are refuted)
Not every expert report is sound. A counter-report does not produce another report: it shows the opposing one is incomplete, incorrect or methodologically deficient.
Not all reports submitted in proceedings withstand rigorous technical analysis. When the opposing party's report contains shortcomings, the response is not to produce another report on the pathology, but a counter-report: a document showing that the rival report's conclusions are incorrect, incomplete or methodologically deficient.
The most common errors
Insufficient inspection: categorical conclusions from a superficial visit, without tests or measurements to support them. Incorrect regulatory references or cited out of context —CTE, EHE-08, LOE applied where they do not belong—. Logical leap between the data gathered and the conclusions. Economic quantification without justification of measurements or prices. Confusion of causes: attributing to one origin what belongs to another.
What the counter-report analyses
The counter-report reviews the methodological rigour of the inspection, the correctness of the regulatory references, the coherence between data and conclusions and the soundness of the valuation. It does not disqualify in the abstract: it points out, item by item, where the opposing report ceases to be defensible.
Why it works before the judge
The judge evaluates expert evidence under the free evaluation standard (LEC art. 348). They are not obliged to accept a report simply because it exists. A counter-report showing concrete deficiencies diminishes the evidential weight of the opposing report.
Frequently asked questions
Can the judge reject an expert report?
The judge does not formally reject it, but freely evaluates its evidential force. A sound counter-report reduces the credit given to the opposing report.
How long does a counter-report take?
It depends on the volume of the report to be rebutted; usually between ten and twenty working days.
Is it the same as challenging the expert (tacha)?
No. The tacha questions the expert's impartiality (LEC art. 343); the counter-report questions the technical content. They can be used together.