How Much Will It Cost? The Truth About Budgeting for a Custom Build or Renovation
If you’re planning a custom architectural build or major renovation, one of the first questions you’ll ask is:
“How much is this going to cost?”
At Goodwin Vaughan, we’ll always give you the most honest answer we can.
And sometimes, that answer is:
“We don’t know yet.”
That might sound confronting—but it’s the truth, and it’s the foundation of a successful project. We’ll never offer a figure before we’ve properly assessed the details. Doing so sets unrealistic expectations and risks disappointment down the track—and that’s not how we work.
Why You Can’t Just Multiply the Square Metres
Looking at a floorplan and elevation doesn’t tell the full story.
To price a project accurately, we need to know:
What’s being touched and what’s staying
What structural changes are involved
What finishes have been selected
What trades are required and how complex the sequencing is
What the site access is like
It’s never as simple as “100 square metres × a set rate = final cost.”
Some projects might come in at $5,000 per square metre, others at $10,000 or more. It depends on the level of finish, the detailing, and the complexity of the design.
There’s no such thing as standard in a custom build.
The Biggest Client Misconception?
It’s Just Like a Regular Build
Architectural builds and major renovations aren’t quick. They’re detailed, layered, and constantly evolving.
They require collaboration between dozens of subcontractors, internal team members, and suppliers to align every element—because in these projects, everything needs to work seamlessly.
What you don’t see on the final drawings:
Sequencing strategies
Mid-build design revisions
Precision carpentry and coordination
Rework due to site constraints
Weeks of discussion behind a single junction detail
So when someone says,
“But my friend got a house twice the size for the same price,”
our answer is simple: Yes—but not the same home, and not the same process.
Ballpark vs Fixed Price: What’s the Difference?
At Goodwin Vaughan, we break our pricing into two clear stages:
1. Ballpark Estimate (Early Design Phase)
Before submitting for Development Approval (DA), we offer a no-cost ballpark estimate.
This isn’t a guess—it’s an informed range based on:
Real data from completed projects
Supplier input
Quick take-offs using our estimating software, Cubit
Ballpark figures from key trades like electricians, plumbers and joiners
It’s not exact, but we aim to be within 5–10% of the final figure.
2. Fixed Price Quote (Post-DA, Full Documentation)
Once structural plans, specifications, and finishes are confirmed, we move into a negotiated tender. Here we:
Review every line item
Lock in supplier pricing
Finalise all inclusions and exclusions
Identify and clearly explain any Provisional Sums or Prime Cost (PC) items
This gives you a fixed contract price based on facts—not assumptions.
What Drives Cost the Most?
Two key factors:
1. Selections
The same item—say, windows—can vary drastically in cost based on material, brand and finish.
Timber vs aluminium? Species and style? These decisions matter.
2. Complexity
More detail means more labour—and labour is one of the biggest drivers of cost.
Carpenters are on site from start to finish, so the more intricate the build, the higher the labour investment.
How We Handle Allowances
We take the time to walk clients through all Provisional Sums and PC items early.
These are placeholder amounts for items or work where the exact scope isn’t yet known.
If the real cost comes in higher, you pay the difference
If it’s lower, we refund the difference
Everything is transparently tracked and reported—so there are no surprises.
Helping Clients Prioritise and Stay on Budget
We rarely sign a contract based on the first number we present.
Instead, we collaborate with clients to reshape and refine the scope in ways that align with their vision and budget.
We ask:
What matters most in this build?
Is it additional bedrooms for a growing family?
A dream kitchen?
High performance and energy efficiency?
From there, we explore:
Deferring lower priority items as future upgrades
Substituting premium materials for more cost-effective alternatives
Staging works to suit budget and lifestyle milestones
This is collaborative cost management, not just value engineering
We’re not just cutting things. We’re reshaping the project to serve your life better
Final Advice for Clients Starting the Journey
If you want to avoid surprises and cost blowouts:
Don’t rely on square metre rates
Invest in detailed plans and selections early
Choose a builder who’s involved well before DA
Ask questions—and expect detailed, honest answers
Most importantly, choose someone who’s honest from the start.
Because it’s not just about what it costs, It’s about what it takes to build it right.