When to Lock In Construction Loan Rates

Construction loan rates work differently because you're not borrowing the full amount upfront.

You only pay interest on what's been drawn down so far, which means your repayments start small and increase as the build progresses. Most lenders charge a variable rate during construction, with the option to switch to a fixed rate once the build is complete and you convert to a standard home loan. If you're building as part of a property settlement or starting fresh after separation, understanding how these rates apply at each stage will help you plan your budget more accurately.

How Interest Is Charged During Construction

You're charged interest only on the amount drawn down, not the total loan amount. If your construction loan is approved for $450,000 but only $150,000 has been paid to the builder so far, you're only paying interest on that $150,000. This is calculated daily and charged monthly, usually on an interest-only basis during the build.

Consider someone building on land they retained in a settlement. The loan is $380,000, but in the first month only the slab has been paid, around $80,000. At a variable rate of 6.5%, they're paying roughly $433 per month in interest at that stage. After the frame goes up and another $120,000 is drawn, the balance is now $200,000 and the monthly interest moves to around $1,083. Repayments increase with each progress payment, so budgeting needs to account for that climb.

Most lenders also charge a progressive drawing fee each time funds are released, usually between $150 and $400 per drawdown. This is separate from the interest rate but still affects your total cost during construction.

Variable Rates During the Build

Most construction loans sit on a variable rate while the build is underway. Lenders prefer this because the loan balance is changing every few weeks as progress payments are made, and it's simpler to manage a variable product during that period. You won't usually have the option to fix the rate until construction is finished and the loan converts to a standard mortgage.

That means if rates rise during your build, your repayments will increase even though the balance is also increasing. In our experience, this can catch people off guard, especially if the build takes longer than expected. A six-month build that stretches to nine or ten months due to weather or council delays means more months of exposure to rate movements.

Fixed Price Contracts and Rate Certainty

A fixed price building contract doesn't lock in your interest rate, but it does lock in your loan amount. That's important because it means you know the total you'll need to borrow, even if progress payments stretch out over time. If the builder quotes $420,000 and you sign a fixed price contract, that's what you'll draw down, assuming no variations.

Without a fixed price contract, cost overruns become your problem. If the builder is working on a cost-plus basis, every extra expense flows through to you, and if your loan isn't large enough to cover it, you'll need to find additional funds or apply for a top-up. When you're rebuilding financial stability after separation, that kind of uncertainty makes planning much harder.

Most lenders will only approve construction finance if you have a fixed price contract in place. It's not just about protecting you, it's about protecting them from lending on a project that could blow out beyond what the valuation supports.

Converting to a Standard Loan After Completion

Once construction is finished and you have an occupancy certificate, the loan converts from a construction product to a standard home loan. That's when you can choose between variable and fixed rates, or split the loan across both. The conversion usually happens automatically, but you'll need to confirm the rate structure you want before it finalises.

If you've been managing interest-only repayments during construction and want to continue that arrangement, you'll need to request it during the conversion. Otherwise, the loan will switch to principal and interest by default. For someone who's also managing other debts or settlement payments after separation, keeping the interest-only option active for a period might make sense while you stabilise your income.

Some lenders allow you to lock in a fixed rate before construction finishes, usually within 90 days of completion. If rates are moving and you want certainty, that can be worth discussing with your broker once the build is in its final stage.

Land and Construction Packages

If you're buying land and building on it as part of a house and land package, the loan is usually structured in two stages. The first drawdown covers the land purchase, and the second stage covers the construction. You'll pay interest on the land from settlement, even if building hasn't started yet.

Most lenders require you to commence building within a set period from the loan settlement, usually six to twelve months. If you miss that window, they may review your borrowing capacity or require a new application. That timeline can be tight if you're waiting for council approval or finalising a development application, so it's worth confirming the builder's schedule before committing to the land purchase.

The interest rate for the land portion is usually the same variable rate that applies during construction, but some lenders will let you fix that portion separately if you prefer. That only makes sense if you expect a long delay before construction starts.

Progress Payment Schedules and Drawdowns

Progress payments are released according to a schedule agreed between you, the builder, and the lender. Typically there are five or six stages: base, frame, lockup, fixing, practical completion, and final completion. The lender will arrange a progress inspection at each stage before releasing funds, and they'll charge a fee for that inspection, usually rolled into the progressive drawing fee.

If the inspector identifies incomplete work or a variation from the approved plans, the drawdown can be delayed. That can create tension with the builder, who may expect payment before moving to the next stage. Most builders build a buffer into their contract for these delays, but it's still worth staying across the schedule and making sure inspections are booked promptly.

You'll need to keep enough cash on hand to cover any gaps between when the builder invoices and when the lender releases funds. Some builders require a deposit upfront, separate from the progress payments, and that comes from your own savings rather than the loan.

When Renovating Instead of Building

If you're renovating rather than building from scratch, the same principles apply but the loan structure is slightly different. A renovation loan still uses progressive drawdowns, but the amounts are usually smaller and the schedule is shorter. You'll need detailed quotes from your builder or tradies, council approval if required, and a clear scope of works before the lender will approve the finance.

Rates for renovation finance are often the same as construction rates, sitting on a variable product until the work is complete. If you're doing minor cosmetic work that doesn't require council approval, some lenders will release the full amount upfront rather than using a drawdown structure, but that's less common if the loan amount is significant.

Owner Builder Considerations

If you're acting as an owner builder, fewer lenders will consider your application, and those who do will usually charge a higher interest rate or require a larger deposit. Lenders see owner builders as higher risk because there's no registered builder providing a warranty or managing the project professionally.

You'll need to show that you have trade qualifications or significant building experience, a detailed project plan, and fixed price quotes from sub-contractors for every stage of the build. Even then, the lender may cap how much they'll lend, often at 80% of the combined land and construction value instead of the 90% or 95% available with a registered builder.

If you're planning to build yourself to save money after separation, make sure you can access enough finance before committing to the land purchase. Owner builder finance isn't something you can assume will be approved just because you have equity or a deposit.

Choosing Between Construction and Buying Established

Construction finance makes sense if you need something specific that the established market can't offer, or if the numbers stack up better when you factor in grants or concessions. But it also means months of variable rate exposure, progress payment coordination, and the risk of builder delays.

For someone rebuilding after separation, buying an established home with a standard mortgage might offer more certainty, even if the upfront cost is slightly higher. You know the purchase price, you can lock in a fixed rate from day one if you want, and you're not managing tradies or council inspections while also managing a settlement process.

That said, if you're buying land as part of a settlement and building suits your situation, construction finance is absolutely workable. It just requires more active management and a larger cash buffer than a standard purchase.

If you're weighing up whether to build or buy, or you need help structuring a construction loan that fits your situation after separation, call one of our team or book an appointment at a time that works for you.

Frequently Asked Questions