PC sum and VO

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What You Need to Know Before Signing a Building Contract

Throughout any design and build journey, two terms will keep coming up: PC sum and VO. Understanding how these work is key to confidently navigating your building contract and avoiding surprises.

What is a PC Sum?

PC sum stands for Prime Cost sum. It’s an estimated allowance included in building contracts for areas of the build where a fixed cost cannot be provided at the time the contract is signed.

The final cost may end up over or under the provision, but a good PC sum is the best possible estimate, based on contractor quotes, professional advice, and careful assessment.

Common examples of PC sums include:

  • Site-related items: Excavations, retaining walls, or other works where costs are unknown until construction begins.

  • Selectable items: Kitchens, wardrobes, tiles, or interior finishes that have not yet been chosen.

PC sums give clients flexibility to explore different options and achieve their design vision while allowing the builder to provide a realistic estimate in the contract.

Fun fact: Some clients think PC stands for Personal Choice, which isn’t technically correct—but it does reflect the purpose of a PC sum!

What is a VO (Variation Order)?

VO stands for Variation Order. While most prices in a contract (except PC sums) are fixed*, clients often want to make changes after signing. For example:

  • Upgrading kitchen appliances

  • Changing fixtures or finishes

The builder calculates the price difference and provides a new quote. Once approved, this becomes a VO.

Both PC sums and VOs usually affect the final contract price, so understanding them is critical to avoiding surprises and staying on budget. Always ask questions and clarify any items before signing.

Why This Matters for Homeowners

Understanding PC sums and VOs helps you:

  • Plan your budget accurately

  • Make informed decisions on finishes and upgrades

  • Avoid surprises in your final contract price

  • Ensure your design and build journey is smooth and stress-free

 Want to Learn More About Building Costs?

Understanding PC sums and Variation Orders is just one part of navigating your building budget. For more tips on transparent pricing and per square metre rates, check out our related blogs:

These guides help you plan confidently and avoid surprises throughout your design and build journey.

You can also contact our design and build consultant anytime to learn more about building costs and get personalised guidance for your project.

*subject to contract terms and conditions

Keegan AndersonMaddren Homes