Additional and modification works in construction contracts

Disagreements often arise in construction contracts regarding the contractor’s additional and modification works. In YSE 1998 (General conditions for building contracts in Finland), additional works are classified as contractor performances that were not initially part of the contractor’s obligations as specified in the contract. Moreover, modification works re considered changes to the performance arising from alterations to the plans underlying the contract.

Disputes generally revolve around whether a specific task should be deemed as an additional or modification work, which would entitle the contractor to compensation and an extension of the project timeline. When evaluating what work is included in the contract, the contents of the contract documents are typically considered. However, plans are often refined during the course of the project, and the contractor is not entitled to additional compensation or an extension of the project timeline for additional and modification works pertaining to tasks that the contractor should have foreseen before signing the contract.

The contractor may also have an obligation to carry out modifications requested by the client, unless they substantially alter the nature of the performance. This is stipulated in section 43 of the YSE 1998 terms. Conversely, the client has an obligation to pay the contractor an additional compensation for modification works.