If you're looking at a block of land in Mosman or on the Northern Beaches and wondering whether the ageing dwelling on it is worth saving, you're asking exactly the right question. Knockdown-rebuilds have become one of the most common ways buyers and existing owners unlock the true value of premium Sydney land - and construction finance is what makes them possible. In my 20-plus years as a mortgage broker, I've helped many clients navigate this process, and the finance side is consistently where people feel least prepared.
Here's how it actually works.
Construction Finance Is a Different Beast
The first thing to understand is that a construction loan is structured completely differently from a standard home loan. Rather than receiving the full loan amount at settlement, the funds are released in stages as your build progresses. This is known as progressive drawdown, and it has a significant impact on both how your repayments work and how your cash flow is managed throughout the build.
Critically, during the construction phase your repayments are interest-only, calculated only on the funds that have been drawn down so far - not the full loan amount. This is genuinely useful. Most people building or rebuilding are also paying rent or living elsewhere during construction, so keeping repayments lower during that period makes the whole project more manageable financially. Once the final drawdown is made at practical completion, the loan converts to principal and interest repayments on the full amount.
What Lenders Need Before They'll Approve
Construction finance approval depends on three things: the land value, the builder's fixed price contract, and your ability to service the total loan amount.
Lenders require a fixed price building contract with a registered builder before approving construction finance. A cost-plus contract, where the builder charges actual costs plus a margin, won't satisfy most lenders. The contract needs to specify the total build cost, the deposit amount, and the progress payment schedule tied to building stages. Lenders also verify the builder's licence, insurance, and track record on comparable projects.
In Mosman and on the Northern Beaches, where land values are significant and build quality expectations are high, construction costs for quality residential builds typically range from around $2,500 to $4,000 per square metre for mid-range luxury, rising to $4,000-$5,500 or more per square metre for high-end architectural homes. A knockdown-rebuild in Mosman might realistically carry a construction contract of $1.5 to $2.5 million and beyond, depending on size and specification - and that contract becomes the foundation of your loan application.
You'll also need development application approval from your local council before construction finance can be finalised. Lenders won't release funds without stamped, approved plans. In Mosman, heritage overlays and design excellence provisions can extend DA approval timelines considerably, so timing your finance application carefully matters - typically once your DA is lodged and progressing, not before.
The Progressive Drawdown Stages
Funds are released directly to your builder upon completion of each stage, usually verified by a lender inspection. The standard stages and approximate percentages are:
- Base/slab stage (15-20%): site preparation, excavation, plumbing rough-in, and the concrete foundation slab
- Frame stage (15-20%): structural frame, exterior walls, roof trusses, and electrical and plumbing conduits
- Lock-up stage (20-30%): external walls, windows and doors installed - the building is now weatherproof and secure
- Fit-out/fixing stage (20-30%): internal fittings including plasterboard, cabinetry, tiling, and electrical and plumbing fixtures
- Completion stage (approx. 10%): final touches, site cleaning, fencing and landscaping
Each drawdown triggers a lender inspection to confirm the stage is genuinely complete before funds are released. This protects both you and the lender, but it also means your builder needs to be prepared for a short delay between stage completion and payment - something worth discussing with them upfront.
How Lenders Assess Land and Construction Separately
This is the piece most people don't anticipate. In premium Sydney markets like Mosman and the Northern Beaches, the land component often represents the majority of the total project value. Lenders assess the land and the construction separately, and they'll calculate your loan-to-value ratio against the end value of the completed property - not just the sum of land cost plus build cost.
This means getting a realistic valuation of the completed home is important early in the process. If the completed value supports the total borrowing, the finance is straightforward. If the lender's valuation comes in below your total project cost, you may need to contribute more equity or reconsider the scope of the build.
Owner Builder Finance
If you're considering acting as your own builder rather than engaging a registered builder, be aware that most lenders treat this very differently. Owner builder applications face stricter criteria, typically lower LVR limits, and some lenders won't touch them at all. If you're considering this path it's worth having an early conversation with a broker before you commit to that approach.
Interest Rates
Construction loan interest rates are broadly in line with standard variable rates - you're not paying a significant premium for the construction period. The key difference, as mentioned above, is that repayments during construction are interest-only on drawn funds. Once construction is complete and the loan converts, your rate and repayment structure will look much like any other home loan.
Getting the Application Right
A complete construction loan application needs the fixed price building contract, council-approved plans, builder's licence and insurance details, land title documentation, evidence of your deposit, and full income and liability documentation. Having all of this ready before you approach lenders significantly speeds up the process.
Given the complexity of construction finance - particularly in high-value markets where the numbers are large and the moving parts are many - working with a broker who regularly handles these applications is worth it. I work with clients across the Northern Beaches and in Mosman on construction and knockdown-rebuild finance regularly, and the process is considerably smoother when the application is structured correctly from the start.
If you're at the early stages of planning a build or knockdown-rebuild and want to understand exactly what's involved, book a free consultation and we can map out the finance side before you commit to anything.
