You hire a builder to demolish and rebuild your house under a “cost plus” contract, meaning you are obligated to pay the builder’s costs plus a 10% margin. To make sure you know what you are paying for, you ensure the contract requires detailed and itemised invoices with every progress payment claim raised by the builder. The builder has one year to complete the house. What would you do when the builder goes over $1 million and 3 years past budget? Would you decline to pay progress payments which did not comply with the contract, because they lacked the itemised costing?
This was the case in Renbar Constructions Pty Ltd v Sader  NSWSC 172. The Court considered whether the builder, Renbar Constructions, was entitled to recover the balance of the building costs incurred in performance of the contract. The Court also considered how much in damages the owner, Dr Sader, would be entitled to for defects, and the significant delay to the completion of construction.
In total the builder raised sixteen progress claims, a dozen of which were paid by the owner despite the progress payment claims being non-compliant with the contract, which required detailed costing. Later, a dispute arose about the true cost and value of the building works, the lengthy delay, and defects with the building works.
The Court found a gap in the contract. On one hand, the contract required the owner to pay the “price of the building works in the manner and at the times stated in the contract”. On the other hand, it required the owner to pay “progressively as claimed” by the builder; claims which needed to be accompanied by invoices for building materials and other documents to entitle the builder to payment. The gap in the contract was found in the circumstances of the case— the owner was obligated to pay for the building works, but the builder was not entitled to payment until a progress claim was issued. Did the contract entitle the builder to payment when the payment claims did not comply with the contract requirements?
The Court found that the contract must have had an implied term that required the owner to pay the price for the building work done within a reasonable time, even though no valid progress payment claims were issued by the builder. The Court may infer that an implied contractual term exists if it is fair, obvious, clear, necessary to give business efficacy to the contract, and not in contradiction with other terms of the contract.
Consequently, Dr Sader could not rely on the lack of a valid progress payment claim as a defence against payment of the balance of the price for the building works. Sader could (and did) claim damages for the building defects and delay as a breach of contract.
Litigation for construction matters can be costly and unpredictable. But this risk can be minimised with the clear and careful drafting of contracts although, as this case shows, even standard form contracts can result in disputes. If it seems a project is becoming contentious, it may be worthwhile to engage legal assistance sooner rather than later to understand your rights and obligations, and before a costly dispute arises.