Some scholars hold the view that in case of a concurrent delay, the contractor is entitled to an extension of time irrespective of whether he could actually have performed himself within the originally agreed time frame.
According to other scholars, there is no absolute right of the contractor to extend a deadline in case of a concurrent delay. According to this view, each case has to be considered individually taking into account the particular situation and the causality. It can be argued that the principal’s participation duties (e.g. delivery of plans) require that the contractor can actually benefit from such participation (e.g. that he is actually ready to start with the respective execution work). This means, that unless the contractor is capable to perform, the principal cannot be in delay with his obligations.
As there is currently very little case law, it remains uncertain how a court would decide these issues.
Neither statutory law nor the general conditions of the Swiss Society of Engineers and Architects for construction contracts provide for an automatic extension of time. According to these provisions, an extension of time can only be granted if the contractor immediately notifies the principal of a delay. An extension of time is only granted for an “adequate” period which is required in order to catch up the delay, as contractors usually already build in some buffer time. The extension of time is therefore not in any case identical with the period of concurrent delay.
If no lump sum price has been agreed, statutory law provides that the contractor’s extra effort that was caused by the principal’s delay has to be considered when determining the compensation for the work. There is, however, no statutory provision which provides for an extra compensation due to a concurrent delay in case of an agreed lump sum price. According to legal doctrine and case law, the contractor could nevertheless claim for additional payment in case of a delay of the principal; such claim can be based by analogy on the principles of change orders.