You have a renovation planned and, instead of using a single general contractor, you opt for several specialist contractors, each with a separate contract. Cheaper, but also riskier. What if the electrician runs his cables in a spot where the plumber later needs to drill? What if underfloor heating is installed on a concrete floor without the concrete work being properly coordinated? When coordination fails, damage often follows. Who pays? The answer requires three separate questions: who coordinated, what did the law expect of each contractor, and how does good faith weigh in?
The starting point under Belgian law is clear: the client who concludes separate contracts with several contractors bears coordination responsibility himself. But the contractors are not released from responsibility towards each other — since a Court of Cassation ruling of 20 May 2021, we know that they have mutual duties of information, advice and warning as soon as their works interfere with one another. In this article, you will read how this shared responsibility is allocated in practice, with the textbook examples on which case law regularly applies it.
Who coordinates: the client or the contractors themselves?
The starting point is clear. When you, as the client, conclude separate contracts with several contractors, you bear coordination responsibility yourself. The draft Book 7 of the Civil Code codifies this principle in article 7.4.10: "Where several contractors take part in the performance of an assignment, each bound to the client by a separate contract, the client shall ensure their coordination."
Under current law, this principle is not expressly enshrined in legislation, but is inferred by the courts from the general contractual structure. Anyone who concludes separate contracts for works effectively assembles their own "team" and bears the logistical responsibility for it. This explains why individuals working directly with independent tradespeople often face a higher risk of damage than clients working with a single general contractor or a construction team.
In practice, this means: you draw up the schedule, you make sure the right party has access to the site at the right time, you keep the overview. If you have delegated that role to an architect or a site coordinator, ultimate responsibility remains with you, but the coordinator can be held internally liable for lack of due care.
The duty of cooperation between contractors
The other side of the coin: contractors are not exempt from their own responsibility. When their works interfere with one another, they are required to inform, consult and warn each other. The draft Book 7 of the Civil Code sets this out in article 7.4.28: "Where several contractors are appointed for the performance of an assignment, each bound to the client by a separate contract, each of them is obliged to cooperate with the other contractors."
This principle is not new. The Court of Cassation confirmed the duty of cooperation as early as its ruling of 20 May 2021 (Cass. AR.20210520.1F.2). Contractors working on the same site have, to the extent necessary and to the extent that their works interfere with one another, mutual duties of information, advice and warning. This obligation flows from the supplementary effect of good faith, as now enshrined in article 5.73 of the Civil Code.
Concretely: a contractor who carries out works without comment that undermine the performance of an earlier contractor, or who fails to warn a fellow contractor when he sees that the latter's work will cause faults in his own later performance, can be held jointly liable. The silent bystander is not an innocent bystander in construction.
A textbook example: underfloor heating on a concrete floor
A classic example is the installation of underfloor heating on a screed poured by another contractor. One contractor pours the concrete, another lays the underfloor heating, a third installs the finishing floor. Each of them has their own technical standards that must be observed — drying times for the concrete, expansion joints for the underfloor heating, adhesion requirements for the finish.
When one of these contractors starts his phase without any communication, before the previous phase is sufficiently completed, and damage arises months later (cracks in the floor, non-functioning underfloor heating, adhesion problems), the reflex is to sue only the "last" contractor. But liability is usually distributed: the earlier contractors also had a duty to warn their colleagues about the execution conditions of their own work.
In a case where the client bound all his contractors by separate contracts, a judge — after an expert investigation — may apply an allocation formula in which each contractor bears his share based on his failure to comply with the duty of cooperation. The client himself may be allocated a share where coordination was demonstrably deficient.
Cumulation with the duty to warn the client
The duty of cooperation between contractors sits alongside — and not instead of — their duty to warn the client. When a contractor sees that a fellow contractor is doing something wrong, he must not only warn that colleague but also inform you as the client. If he fails to do so, he remains liable for the damage — regardless of his own technical performance.
This is the case, for example, when a contractor sees that his colleague is pouring the screed on unstable ground, or that electrical cables are not being integrated in accordance with the AREI (General Regulations on Electrical Installations). For the details on this duty to warn, see the spoke on the contractor who failed to warn.
How do you properly record this in your contracts?
For projects with multiple contractors, a minimum set of arrangements is crucial. In practice, it is advisable to include in each individual contract:
An express cooperation clause in which the contractor undertakes to exchange information with other contractors on site. A reference to a coordinator (whether or not the client himself) and his power to give instructions. A provision on site meetings with mandatory attendance and minutes. A clause on reservations at acceptance: each contractor accepts that his work will only be finally accepted after subsequent contractors have successfully completed their phases.
Such clauses are not required by law but significantly strengthen your position if a dispute arises later. For more on how to legally frame the entire relationship with your contractors, see the pillar on rights and duties of the client in construction contracts.
What if you have no written contract with all your contractors?
Not unusual. For smaller works, people often operate on the basis of a quotation and a verbal agreement. The duty of cooperation between contractors nevertheless remains fully applicable — it flows from the supplementary effect of good faith, not from an express contractual clause. Proof of the contract itself can also be provided without a written document, as the Court of Cassation confirmed in its ruling of 5 December 2022 (Cass. AR C.22.0134.N) on proof through the conduct of the parties. Read more about this in the spoke on working without a written construction contract.
And if damage has already occurred?
In cases of coordination damage between contractors, an adversarial expert investigation is usually the first step. A court-appointed expert can establish who did what, when, and which failure is attributable to which party. On that basis, an allocation formula can be proposed that allows you to recover damages from each responsible contractor.
Do you have a case involving multiple contractors and are you unsure whom to hold accountable? Reius Advocaten assists individuals and companies with coordination disputes, from the initial findings to the final decision. Contact us at info@reius.be for an initial analysis of your case.