Under Polish law there are no statutory rules for delay and/or allocating risks and responsibilities to the parties in the event of concurrent delay. There is also no established case law dealing with concurrent delay. Potential claims of the parties relating to concurrent delay are dealt with according to the rules for defective performance/non-performance and for compensation of damages relating thereto.
The general rule under Polish law is that damages are due only if the delay is culpable. Therefore, unless the contract provides otherwise, the contractor can only claim costs of the extended performance of the contract from the employer if the extension was caused by the employer’s fault.
At the same time, in a judgment of 27 September 2013 (I CSK 748/12) the Supreme Court stated that contractual penalties imposed on the contractor after a delay caused by the employer are not acceptable for being in conflict with the principle that a debtor cannot be in delay if the creditor is in delay.
Therefore, if the contract provides for contractual penalties for delay, in the situation where the delay was caused by both, the employer and the contractor, the contractor will not pay contractual penalties for delay but will also not be able to claim the costs of the extension from the employer (depending on the employer’s contribution to the contractor’s delay in performing the work).
Delay might be caused by both the employer and contractor where the contractor has delayed in performing the works and the employer has delayed in co-operating with the contractor, especially handing-over the construction site, providing permits required to perform the works, informing about circumstances impacting the course of the works, etc. or other circumstances delaying the works caused by the employer (e.g. instructed variations).
Therefore, a delay caused by both the employer and the contractor would be a delay in performance of the works for which the contractor is partially liable as the delay was caused also, to the certain extent by the employer e.g. by delay in handing-over the construction site to the contractor. Consequently, the employer’s delay must be at least one of the reasons (must contribute) to the contractor’s delay in performing the works. Depending on the extent of such contribution the contractor may be still liable towards the employer for delay damages (if the employer’s breach of the contract was minor and did not significantly contribute to the contractor’s delay).