Evidence in the law on contracts for work and services

In the law governing contracts for work and services, which regulates the relationship between the client and contractor, various problems of proof can arise that make it difficult to resolve disputes. These problems often concern the determination of defects, breaches of contract or the fulfilment of obligations. Some of the central problems of proof in the law on contracts for work and labour are highlighted below.

Hidden defects:

A common challenge lies in the identification of hidden defects. These only become apparent after a certain period of use or under special conditions. The burden of proof that such defects already existed at the time of handover often lies with the client. Technical reports or the involvement of experts may be necessary to provide evidence.

Providing evidence in the case of verbal agreements:

Not all agreements are set out in writing, and verbal agreements can lead to uncertainty. The burden of proof regarding verbal agreements lies with the party asserting them. The absence of written documentation can make the burden of proof considerably more difficult.

Proof of freedom from defects:

Contractors often endeavour to prove that their performance is free of defects. Proving this can be complex, especially if the fulfilment of quality standards or contractual requirements is difficult to measure. Documentation, test protocols and evidence of compliance with standards are crucial in proving freedom from defects.

Question of culpability in the event of breaches of contract:

If a breach of contractual obligations occurs, the question of fault arises. Proving fault can be problematic in some cases, especially if there is no clear evidence. Witness statements, correspondence or other written documents can help to prove or disprove fault.

Providing evidence during the course of the project:

The prompt presentation of evidence during the term of the contract is crucial. Complete documentation of project progress, coordination and changes can serve as evidence in the event of a dispute. Failure to provide documentation during the project can make it considerably more difficult to provide evidence later on. After delivery of the work, the customer must, as soon as it is feasible in the normal course of business, inspect its condition and inform the contractor of any defects (Art. 367 para. 1 CO). Each party is entitled to demand an inspection of the work by experts and the certification of the findings at its own expense (Art. 367 para. 2 CO).