Persimmon Homes (South Coast) Ltd v Hall Aggregates (South Coast) Ltd [2009] EWCA Civ 1108; [2009] PLSCS 289 provides an interesting insight into the law that applies where a party to a contract is obliged to carry out work but stands by and allows a counter-party to do the work instead. The dispute concerned a site that had been used for sand and gravel extraction and subsequently for landfill. The landowner agreed to remediate the land at its own expense following its sale. None the less, the developer undertook the work itself, without requiring the seller to do so. In due course, the developer sought to recover the cost from the seller. The seller acknowledged that it had: (i) been fully aware of its contractual obligations; (ii) known that the developer was undertaking the work; and failed to advise the developer of its apparent error. The High Court ruled that if performance of a contractual obligation is contingent on a request or the occurrence of some specified event the contract must expressly say so. The contract with the developer did not contain such a provision. Consequently, the obligation to remediate the land was mandatory and the seller was liable in damages. The seller appealed. It argued that the contract required the work to conform to the developer’s “reasonable requirements”. It claimed that these words created a condition precedent to its obligation to undertake the work and that the developer’s conduct had shown that it did not require the seller to carry out the work. Alternatively, it argued that the developer had waived its rights and questioned the calculation of damages. The Court of Appeal decided that it would not make sense to hold that the words requiring the work to conform to the developer’s reasonable requirements were a condition precedent to the obligation to perform the work. As a matter of construction, the words dealt with the manner in which the work was carried out. Their lordships also rejected the argument that the developer had waived its rights. They ruled that it had not unequivocally represented to the seller (by words or conduct) that it was waiving the performance of the obligation to remediate the land. In addition, for a waiver to be effective, the other party must act on a representation to its detriment or must conduct its affairs on the basis of such a waiver. The seller had not acted in a way that satisfied either of these requirements. Finally, the court ruled that the proper measure of damages for the seller’s breach of contract was the notional cost to the seller of the remediation work that it had been obliged to perform (as opposed to the costs actually incurred by the developer). The decision indicates that the courts will not allow parties to contracts to profit from their silence and that nothing is to be gained from allowing counter-parties to undertake work for which they are not contractually responsible because liability for such work has been assigned to another party. Allyson Colby is a property law consultant