What exactly does the duty to warn entail?
The essence of Article 7:754 of the Civil Code (hereinafter: BW) is that the contractor, when he knows or should know that there is an error in the order (and executing this order without thought may lead to damage), is obliged to point out this error to the client and warn him of the possible consequences. Whether this is the case depends on the expertise that may be expected of him as a contractor and the care that may be required of him under the circumstances. In principle, it is assumed that a contractor - as the executing party - is always expert in the field of his own work and must therefore warn against errors.
For roofers, this means that they must pay close attention while performing their work. For example, if insulation materials are used that are not suitable for the intended roof, the roofer must explicitly inform the client. Ignoring this duty can have significant legal consequences, as the following example shows.
Duty to alert in practice
A 2022 ruling by the Court of Zeeland-West Brabant(ECLI:NL:RBZWB:2022:8636) provides important insight into how the duty to warn contractors works in practice and specifically what the consequences are if this duty is not met. This case involved a contractor whose business is (among other things) the insulation of homes. As a result of the insulation work, the applied polyurethane foam flowed back out through the drilled holes.
The court ruled that the contractor has a duty to warn, as laid down in Section 7:754 of the Civil Code. In this regard, the contractor should be expected to be aware that insulating a home with cavity deterioration could lead to damage and to explicitly warn the client about this.
The contractor in this case knew that there was cavity wall contamination. He had indicated to the client that performance was at the client's own risk. However, this was not a sufficient warning, the court said. The contractor should have explicitly warned and alerted the client to the (possible) consequences. After all, this warning gives the client the opportunity to take measures to prevent damage. The contractor failed in his duty to warn and was therefore held liable for the damages suffered as a result (by the client).
In another matter, the contractor should have warned the client of the risk that the roof, with the panels desired by the client and the slope angle calculated by the client, would not be rainproof. It should have been incumbent on the contractor to realize that the roof in question had too low a pitch to produce a rainwater-tight roof with the panels desired by the client. Since the contractor failed to warn, the client was entitled to assume that the roof would be rainproof. The contractor breached his duty to warn. Court of Appeal of 's-Hertogenbosch ruled that the contractor had failed to fulfill the parties' building contract.
In short: put the warning expressly made in writing for that reason. The moment questions of proof arise, you will always benefit from the concrete recording of the warning. You are therefore (in principle) obliged to prove that you have complied with the warning obligation.
What does this mean for you?
Based on the above, it is important that you, as a professional, comply with the duty to warn. If something is, or could go wrong, state this explicitly and in writing. Point out the possible consequences of the mistake and - if possible - provide alternatives. Failure to comply with the duty to warn can have major and adverse consequences. In theory, the contractor may be fully liable for damages suffered by the client. Even if the design risk rests with the client. In short: watch out!
