Understanding Contract Variations

Contract variations, often a focal point in construction agreements, refer to the changes or modifications made to the initially agreed terms of a contract. In the context of the Master Builders Association Head Contract Residential Building (BC4) for NSW, these variations cover a range of alterations, from executing additional work to decreasing or omitting works to adjusting the quality of materials due to latent conditions. 

Such variations are typically established through written instructions, updated plans, or even the discovery of previously unknown conditions. For builders, it’s essential to grasp that these variations aren’t merely administrative changes. They can have profound legal and financial implications. Recognising when a task falls outside the original contract’s scope and understanding the mechanisms to claim for these variations are crucial for builders to ensure they are adequately compensated and protected against potential disputes.

The MBA Contract Residential Building (BC4) outlines the terms and procedures for dealing with variations. One key requirement is that variations must be in writing and signed by both homeowner and builder. However, there are instances when these variations are not documented as they should be. This is where quantum meruit comes into play.

Understanding Quantum Meruit Claims

Quantum Meruit, a Latin term meaning “what one has earned”, plays a pivotal role in the construction landscape. Quantum Meruit is a legal principle allowing a party to claim reasonable remuneration for services rendered or work done when a contract is either non-existent or unenforceable. In the context of the MBA Contract BC4, Quantum Meruit claims arise when builders undertake work outside the contract scope, expecting rightful compensation. Such claims are relevant when variations occur without formal agreement or when unforeseen circumstances affect the original contract. For builders in NSW, understanding Quantum Meruit is not just about knowing the law; it’s about ensuring they receive fair value for their work, especially in complex contractual scenarios.

Legal Principles Behind Quantum Meruit

At its core, Quantum Meruit operates on the principle of fairness and equity. It ensures that a party is justly compensated for services rendered, even in the absence of a formal contract. 

Two pivotal cases, Durastyle Homes Pty Ltd v Gosling; Gosling v Durastyle Homes Pty Ltd [2022] NSWCATCD 106 and Nayak v Rockwall Constructions Pty Ltd [2017] NSWCATAP 18, have outlined the criteria for a successful Quantum Meruit claim in NSW:

  1. The work must be outside the contract;
  2. The homeowner must know of the variation as they were being done;
  3. The homeowner must know that the work is outside the contract;
  4. The homeowner must know that the builder expected to be paid for the work as variation to the contract; and 
  5. The builder had provided evidence that the amount claimed was fair value.

Practical Implications for Builders

For builders, quantum meruit is a practical tool in navigating the complexities of construction projects. When contract terms are unclear or when unexpected changes arise, quantum meruit offers a safety net, ensuring builders are not left uncompensated. 

However, quantum meruit is not a free pass for builders. Builders must still be diligent in documenting variations, communicating with homeowners, and ensuring transparency in their expectations. Failing to do so can lead to disputes, legal battles, and financial losses. Moreover, with the intricacies of the MBA Contract BC4 and the Home Building Act 1989 (NSW), builders must be proactive in understanding their rights and obligations, safeguarding their interests in every project phase.

Case Studies: Quantum Meruit in Action

Real-world scenarios offer invaluable insights into the practical application of Quantum Meruit. In the case laws cited above, the court outlined five essential criteria for a successful Quantum Meruit claim, emphasising the importance of the owner’s knowledge and the builder’s expectation of payment. They also highlighted the need for work to fall outside the contract’s purview. These cases underscore the significance of clear communication, proper documentation, and mutual understanding between parties. For builders, these case studies serve as a roadmap, guiding them in navigating the complexities of Quantum Meruit claims and ensuring rightful compensation.

Quantum Meruit Payment A Builder's Legal Guide (MBA Contract BC4)


Navigating Quantum Meruit claims and contract variations can be challenging. However, with a clear understanding of the legal principles, case studies, and practical implications, builders can confidently assert their rights and ensure fair compensation. As the construction landscape evolves, staying informed and seeking expert advice are crucial.

If you’re a builder facing challenges with Quantum Meruit claims or variations under the MBA Contract BC4, seeking professional guidance is important. With over a decade of specialised experience in construction law, I have been at the forefront of advising and representing both homeowners and builders in NSW’s tribunals and courts. My expertise includes Quantum Meruit Claims, Variations, and a deep understanding of the MBA Contract BC4. I’m committed to ensuring that your contractual rights are upheld, risks are mitigated, and your intentions are clearly reflected in your contracts. Reach out today for a free consultation and let’s navigate these complexities together.