Under the 2018 ICC Target Cost Contract can the Engineer disallow costs related to defects prior to completion on the grounds that it is a breach of contract. If yes should the cost of the initial work be disallowed or the rectification cost (could be more or less than initial cost depending on circumstances
In my experience the contractor has a right and an obligation to rectify any defects during the defects liability period (or before) (See Clause 10.5 of the contract). Having a defect is not breach of contract. Failing to rectify it would result in the employer making arrangements for the defect to be rectified at the contractors cost after appropriate notice has been given.
Based on this you cannot disallow any costs for defects until such time as it is clear they will not be remedied within the timescales allowed. (These are my own views not that of my company)