Everything You Need to Know About Buying a Duplex

Purchasing a Duplex as Your First Property

Buying a duplex as a first home buyer gives you the option to live in one unit and rent out the other, offsetting your mortgage repayments from day one. The Australian Government 5% Deposit Scheme allows eligible first home buyers to purchase with a 5% deposit without paying lenders mortgage insurance, and in Victoria, the property price cap is $950,000 for capital city and regional centres.

Parkdale sits close to the bay with proximity to Mentone and Mordialloc, and duplexes in the area typically attract young families and professional renters. Most duplexes here are newer builds or recent subdivisions, which means they often qualify for the stamp duty concessions available to first home buyers purchasing new or established homes in Victoria.

What Lenders Look for in a Duplex Purchase

Lenders assess a duplex purchase differently depending on whether you intend to occupy both units or rent one out. If you plan to live in one side and lease the other, the lender will treat the loan as part owner-occupied and part investment. Your borrowing capacity will reflect both your household income and a portion of the expected rental income from the tenanted unit, usually around 80% of the assessed market rent.

Consider a buyer purchasing a two-bedroom duplex in Parkdale. They plan to live in one unit and lease the other for $450 per week. The lender includes 80% of that rental income, or $360 per week, in the servicing calculation. That additional income can lift borrowing capacity by $80,000 to $100,000 depending on the buyer's existing commitments and the lender's assessment rate. The loan is split into two portions with different loan-to-value ratios, and the interest rate on the investment component may differ slightly from the owner-occupied rate.

How Stamp Duty Works on a Duplex in Victoria

Victoria offers a full stamp duty exemption on properties valued up to $600,000 and a sliding scale concession on properties valued from $600,001 to $750,000. The exemption applies to both new and established homes where the property will be the buyer's principal place of residence. You must move into the home within 12 months of settlement and live there for at least 12 continuous months.

If the duplex is a new build or part of a community titles scheme purchased off-the-plan, you may also qualify for the off-the-plan concession, which calculates duty on the land value at contract date only. That concession applies to strata or community title contracts signed on or before 31 October 2026 for properties not yet titled or substantially completed. When one half of the duplex will be your principal place of residence and the other will be tenanted, the stamp duty concession applies only to the portion you occupy. The investment portion is subject to standard duty rates.

Structuring Your Loan Between Owner-Occupied and Investment

When you purchase a duplex with the intention of living in one unit and renting the other, most lenders will require the loan to be split into two accounts. One account is classified as owner-occupied and attracts the lower interest rate. The other is classified as investment and may carry a slightly higher rate, typically 0.10% to 0.20% above the owner-occupied rate.

The split is determined by the lender's valuation. If the duplex is valued at $900,000 and each unit is assessed as equal, the loan is split evenly. If one unit is larger or more valuable, the split reflects that difference. Splitting the loan also allows you to attach an offset account to the owner-occupied portion while claiming tax deductions on the interest paid against the investment portion. You cannot claim a deduction on interest relating to the unit you live in, so keeping the two loans separate from the outset protects your ability to maximise deductions without triggering a later restructure.

Deposit Requirements and LMI Considerations

Under the Australian Government 5% Deposit Scheme, eligible first home buyers can purchase with a 5% deposit, and Housing Australia guarantees the difference between the deposit and 20% of the property value. No LMI is payable under this scheme. Applications are made through a participating lender, and first home buyers should confirm which loan features are available under the scheme with their chosen lender.

If you do not qualify for the scheme or the duplex exceeds the price cap, a 10% deposit with LMI remains an option. LMI on a duplex where part of the property will be tenanted is calculated on the full loan amount. Premiums vary depending on the lender, the loan-to-value ratio, and whether the property is classified as standard residential or a higher-risk security type. Some lenders classify a duplex differently from a single dwelling, which can affect both the interest rate and the LMI premium.

Using Rental Income to Boost Your Borrowing Capacity

One of the advantages of purchasing a duplex as a first home buyer is the ability to use projected rental income to support your home loan application. Lenders will usually include 80% of the market rent when calculating serviceability. That rental income can materially increase your borrowing capacity, particularly if you are purchasing at the upper end of your budget.

In our experience, buyers in Parkdale who secure a tenant before settlement often negotiate a lower interest rate with their lender. A signed lease provides certainty and removes the lender's need to estimate rental income. If you are purchasing an established duplex with an existing tenant in place, provide the current lease agreement and rental ledger as part of your application. That documentation strengthens your position and may allow the lender to include the full contracted rent rather than a discounted estimate.

Pre-Approval and Timing Your Purchase

Obtaining pre-approval before you start looking gives you clarity on your budget and confidence when you make an offer. For a duplex purchase, pre-approval should specify both the owner-occupied and investment components, along with the projected rental income the lender is prepared to accept. Not all lenders treat duplex purchases the same way, and some will not lend against certain property types or layouts.

Pre-approval is typically valid for three to six months. If you are purchasing off-the-plan or waiting for a new duplex to be built, confirm with your lender that the pre-approval can be extended or reissued closer to settlement. Interest rates and lending policies can change during construction, and a pre-approval from 12 months earlier may no longer reflect current terms. Buying your first home with a clear understanding of your loan structure and timing reduces the risk of delays at settlement.

Offset Accounts and Tax Deductibility

An offset account linked to the owner-occupied portion of your loan reduces the interest you pay without affecting your ability to claim deductions on the investment portion. Funds in the offset account reduce the balance on which interest is calculated, and because the account is linked only to the non-deductible loan, your savings are not diluted.

You should not link an offset account to the investment loan. Doing so reduces the interest you pay on that loan, which in turn reduces your tax deduction. Keep the investment loan separate, pay interest in full, and claim the deduction at tax time. If you later decide to move out of the duplex and rent both units, you can restructure the loans accordingly, but any restructure should be discussed with a tax adviser to avoid unintended consequences.

Call one of our team or book an appointment at a time that works for you. We work with first home buyers in Parkdale and across the bayside area to structure loans that reflect both your immediate needs and your longer-term plans.

Frequently Asked Questions