Funding an extension differs from standard home finance because lenders release funds progressively as building work reaches specific milestones, rather than providing the full amount at settlement.
Most South Yarra homeowners who extend their properties use a construction loan structured to draw down funds as the project progresses. The lender holds the total approved amount but only releases portions once your builder completes each stage and a quantity surveyor or bank valuer confirms the work. You pay interest solely on the amount drawn down at any given time, not on the full approved sum sitting unused.
How Progressive Drawdowns Match Building Stages
Construction finance releases funds in instalments that align with your builder's progress payment schedule. Typically, this involves four to six stages: base or slab, frame, lock-up, fixing, practical completion, and final completion. Your lender engages a valuer to inspect the site at each stage, verifying the work matches the contracted scope before authorising the next payment.
Consider a South Yarra property owner adding a two-storey rear extension with additional living areas and a main bedroom suite. The builder quotes a fixed price contract at $280,000. The lender approves this amount but releases it across five stages. After the base stage is complete and inspected, the first drawdown of approximately $56,000 flows to the builder. Interest accrues only on this $56,000 until the frame stage triggers the next release. By practical completion, the full $280,000 has been drawn, and the borrower transitions to standard principal-and-interest or interest-only repayments depending on their loan structure.
Most lenders charge a Progressive Drawing Fee for each inspection and release, usually between $300 and $500 per drawdown. Some bundle this into an upfront fee covering all stages.
Fixed Price Contracts and Why Lenders Prefer Them
Lenders strongly favour fixed price building contracts because they establish a clear maximum cost from the outset. Under this arrangement, your builder agrees to deliver the entire project for a specified sum, regardless of cost overruns on materials or labour. If the builder underestimates expenses, they absorb the difference.
A cost plus contract, where you pay the builder's actual costs plus a margin, introduces uncertainty that most mainstream lenders will not accept for owner-occupied extensions. Without a fixed ceiling, the lender cannot determine the final loan amount required or assess serviceability accurately. Only specialist lenders or private financiers typically fund cost plus arrangements, and their rates sit well above standard construction finance.
Using a registered builder rather than owner builder finance also matters. Lenders require evidence of the builder's qualifications, insurance, and track record. In Victoria, this means checking the builder holds current registration with the Victorian Building Authority and that the project is covered by domestic building insurance. South Yarra sits within the City of Melbourne and City of Stonnington council areas, depending on your street, so council approval and a building permit from the relevant authority must be in place before the first drawdown occurs.
Structuring Repayments During the Build
During construction, most lenders offer interest-only repayment options, meaning you pay only the interest charged on drawn funds each month without reducing the principal. Once the project reaches practical completion, the loan converts to a standard home loan with principal-and-interest repayments calculated over the remaining term.
If you already hold a mortgage on the property and are borrowing additional funds for the extension, you have two main approaches. Some borrowers refinance the entire mortgage into a new construction facility, consolidating the existing debt and the new extension funding under one loan with a single progressive drawdown structure. Others keep the existing mortgage untouched and establish a separate construction loan for the extension amount, particularly if their current rate is lower than available new rates or if they want to avoid break costs on a fixed rate loan.
In a scenario where a South Yarra homeowner has $450,000 remaining on their mortgage and needs $300,000 for an extension, they might refinance the full $750,000 into a new construction loan if doing so secures a lower rate or better features. Alternatively, they retain the $450,000 mortgage and add a separate $300,000 construction facility. During the build, they pay interest on the $450,000 existing mortgage as usual, plus interest on whatever portion of the $300,000 construction loan has been drawn. Once building finishes, both loans continue as standard home loans, or they refinance again to consolidate.
How Council Approval and Timing Affect Drawdown Schedules
Your lender will require proof of council approval and a valid building permit before they issue formal loan approval and certainly before releasing the first drawdown. The development application process in South Yarra can involve heritage overlays or neighbourhood character considerations, particularly in streets near Chapel Street, Toorak Road, or within the heritage precincts surrounding Como Park. Extensions that alter the front facade or exceed certain height limits often require a planning permit in addition to a building permit.
Most construction loan approvals remain valid for six to twelve months, and lenders typically require you to commence building within a set period from the loan disclosure date. If your council approval or builder availability delays the start date beyond this window, you may need to reapply or extend the approval, which can involve reassessing your financial position and potentially a new valuation.
Once building starts, the progress payment schedule in your building contract should align with the lender's drawdown stages. Mismatches create cash flow problems. If your builder expects payment at six stages but your lender only funds at four, you either negotiate revised milestones with the builder or cover the gap with your own funds between drawdowns.
Using Existing Equity to Fund the Extension
Most South Yarra homeowners fund extensions by releasing equity from their property rather than contributing significant cash. If your property is valued at $1.6 million and you owe $450,000, you have $1.15 million in equity. Lenders typically allow you to borrow up to 80 per cent of the property's current value without incurring lenders mortgage insurance, meaning a maximum loan of $1.28 million. Subtracting your existing $450,000 debt leaves $830,000 available for the extension and associated costs.
Your lender will assess serviceability based on the final loan amount, not just the extension cost. If your income comfortably services a $750,000 total loan but not $1 million, the amount you can borrow for the extension is constrained by serviceability, not just equity.
Construction finance applications require more documentation than standard home loans. Lenders want the building contract, council plans, evidence of council approval, a detailed cost breakdown, proof the builder is registered and insured, and confirmation that progress inspections will occur at each stage. Processing times are longer, often four to six weeks from application to formal approval, so starting the finance process before finalising your builder avoids delays once you are ready to start.
Call one of our team or book an appointment at a time that works for you to discuss how construction finance applies to your specific extension project and property circumstances.
Frequently Asked Questions
How does progressive drawdown work for an extension project?
The lender releases funds in instalments as your builder completes each stage, such as base, frame, lock-up, and practical completion. A valuer inspects the work at each stage before the lender authorises the next payment. You only pay interest on the amount drawn down at any given time, not the full approved loan amount.
Why do lenders prefer fixed price building contracts?
Fixed price contracts establish a clear maximum cost from the outset, allowing lenders to assess the final loan amount and your ability to service it accurately. Cost plus contracts introduce uncertainty that most mainstream lenders will not accept for owner-occupied extensions.
Can I keep my existing mortgage and add a separate construction loan?
Yes, you can retain your current mortgage and establish a separate construction loan for the extension amount. This approach makes sense if your existing rate is lower than new rates or if you want to avoid break costs on a fixed rate loan.
What council approvals are needed before the first drawdown?
You need a valid building permit and, depending on your property's location and the scope of work, a planning permit before the lender releases the first drawdown. South Yarra properties may be subject to heritage overlays or neighbourhood character considerations that require council planning approval.
How long does a construction loan approval remain valid?
Most construction loan approvals remain valid for six to twelve months. Lenders typically require you to commence building within a set period from the loan disclosure date, so delays in council approval or builder availability may require extending or reapplying for finance.
