Although the concept of force majeure is recognised by the Swiss courts, there are no provisions in Swiss law on this matter. The legal concepts that are most similar and on which one relies for the defence of force majeure are the impossibility of performance (Art. 119 of the Swiss Code of Obligations) and the change of circumstances in the sense of hardship or "economic impossibility" (clausula rebus sic stantibus). Based on the freedom of contract, the parties are free to include provisions on force majeure in their agreement. Therefore, each individual case must be assessed separately.
With regard to an extension of the deadline, the provisions of the specific contract take precedence. If the Contractor is entitled to extend the deadline, no contractual penalty is due in case of a justified extension of the deadline. As a rule, damages are only payable if the contractor is at fault. This does not appear to be the case with COVID-19.
If the contract refers to the provisions of the SIA standard 118 and does not contain a contrary provision, there is an extension of the deadline in the event of delays for which the contractor is not responsible, even though the contractor has taken additional precautions (e.g. natural influences, delivery disruptions, official measures). The contractor has to notify the client and to propose acceleration measures. Such measures may only be taken with the consent of the client. The costs arising from this shall be borne by the client.
In the event of extraordinary circumstances, there is a claim to additional payment in accordance with Art. 373 Para. 2 of the Swiss Code of Obligations and Art. 59 of SIA Standard 118, if unforeseeable circumstances prevent completion or make it excessively difficult. Here too, however, the specific contract for work and services must be checked to see whether any deviating agreements exist.