Planning a Custom Home Build? Here's How Funding Works

Building a custom home means you control the design, the builder, and the timeline. It also means your finance structure needs to match how construction actually happens, with funds released progressively as work reaches specific stages rather than in a single upfront payment.

Understanding how construction funding aligns with your building contract determines whether your project stays on budget and on schedule.

How Progressive Drawdown Works with Fixed Price Building Contracts

With custom home finance, lenders release funds in instalments that match your progress payment schedule. Under a fixed price building contract, your builder submits invoices at set milestones such as slab completion, frame-up, lock-up, and practical completion. The lender arranges a progress inspection to verify the work, then releases that portion of the loan amount directly to the builder or into your nominated account.

Consider a client building a custom-designed home in Brisbane's western suburbs with a contract price of $680,000. Their lender approved a land and construction package, with the land component of $320,000 settled first. Construction drawdowns were structured across six stages: base stage at $95,000, frame stage at $125,000, lock-up at $160,000, fixing stage at $140,000, practical completion at $125,000, and final completion at $35,000. At each stage, their broker coordinated the inspection and drawdown request. Because the contract was fixed price, the client knew exactly what would be drawn at each milestone. They only paid interest on the amount drawn down at each stage, keeping holding costs lower during the build period compared to borrowing the full construction amount upfront.

Interest Charges During Construction

You only pay interest on funds the lender has released, not on the total approved amount. This means your repayments increase gradually as each drawdown occurs. Most lenders offer interest-only repayment options during the construction phase, switching to principal and interest once the build completes and you move in.

Using the example above, after the first three stages totalling $380,000 had been drawn, the client's monthly interest cost at typical construction loan interest rates was calculated only on that $380,000 plus the land component they'd already settled. The remaining approved funds sat undrawn, incurring no interest. When the project reached lock-up, they switched from their rental property into the partially completed home under a occupancy arrangement with their builder, reducing their overall housing costs even before final completion.

Council Approval and Timing Requirements

Lenders require full council approval and stamped building plans before they'll issue formal loan approval for the construction component. Most construction loan approvals also include a condition requiring you to commence building within a set period from the disclosure date, typically six months. If your development application or council plans aren't finalised before applying, some lenders will issue conditional approval based on draft plans, but funds won't be available for drawdown until all approvals are in place.

In our experience, buyers who engage their registered builder and lodge council applications before approaching a lender can often settle land and begin construction within three to four months of initial approval. Those still working through design or awaiting development application outcomes may face longer timeframes, which can affect locked-in interest rates or require approval extensions.

Owner Builder Finance and Cost Plus Contracts

If you're taking the owner builder route or working under a cost plus contract, the funding structure becomes more detailed. Lenders view owner builder projects as higher risk and typically require more documentation at each drawdown stage, including invoices from individual subcontractors such as plumbers, electricians, concreters, and framers. You'll need to demonstrate that funds released in previous stages have been used appropriately before the next drawdown is approved.

Under cost plus arrangements, where your final build cost isn't fixed upfront, lenders usually require a detailed cost breakdown and may hold a contingency buffer. The progressive payment schedule needs to account for variations, and you'll generally pay a progressive drawing fee at each stage to cover the lender's inspection and administration costs. These fees typically range from $300 to $500 per drawdown depending on the lender and location. Owner builder finance usually requires a larger deposit, often 20% to 30%, compared to registered builder projects where 10% deposits are more common.

What Happens If Your Build Exceeds Budget

When actual construction costs run higher than your approved loan amount, the lender won't automatically increase your facility. If you're halfway through a project and need additional funds, you'll need to demonstrate sufficient equity in the partially completed dwelling and submit a new valuation. Lenders assess this as a variation to your existing approval, which can delay progress payments while the reassessment occurs.

This scenario occurs more often with cost plus contracts or where clients make material upgrades mid-build without adjusting their finance structure upfront. Ensuring your borrowing capacity includes a buffer for potential variations means you're not forced into construction delays or out-of-pocket costs when decisions change during the build.

Moving from Construction to Permanent Loan

Most construction facilities automatically convert to a standard home loan once your build reaches practical completion and you've received the occupancy certificate. The interest-only period ends, and repayments adjust to principal and interest based on the full drawn amount. Some lenders offer a construction to permanent loan structure where the post-construction rate and features are locked in at the time of initial approval, while others reassess your loan structure at conversion.

If you're planning to refinance to access better ongoing rates or features after completion, you can do so once the property has been independently valued as a finished dwelling. Lenders treat this as a standard refinance application rather than construction finance, which often opens up access to a wider range of loan products and potentially lower rates than those available during the build phase.

Your finance structure should match how your project actually unfolds, from council submission through to moving in. Call one of our team or book an appointment at a time that works for you to discuss how construction funding applies to your specific build.

Frequently Asked Questions