Investment property due diligence: what a buyer's agent does for you

Every investment decision starts with the cash flow. A property can look appealing on inspection day and still lose you money every month. Financial due diligence tests three things: the rental yield, the prospects for capital growth, and whether the holding costs leave you in front or behind.

Gross rental yield is the annual rent divided by the purchase price. Net yield is more honest because it subtracts the real costs of ownership: council rates, water, insurance, property management fees, strata levies and an allowance for maintenance and vacancy. A property with a 4.5 per cent gross yield can easily fall to 3.1 per cent net once those costs come out.

Capital growth potential is harder to measure but matters more over a ten year hold. A buyer's agent assesses it through the fundamentals: population growth, infrastructure spending, land scarcity, the ratio of owner occupiers to renters, and the gap between the suburb median and its neighbours. The Australian Bureau of Statistics publishes the population and dwelling data that underpins this work.

Here is a worked cash flow for a hypothetical 650,000 dollar apartment returning 540 dollars per week in rent.

Item	Annual amount
Gross rent (540 per week)	28,080
Council rates	-1,650
Water and insurance	-1,400
Strata levies	-4,200
Property management (7 per cent)	-1,966
Maintenance and vacancy allowance	-1,800
Loan interest (520,000 at 6.1 per cent)	-31,720
Pre-tax cash flow	-14,656

This property is negatively geared by roughly 14,656 dollars before depreciation and tax. Whether that is acceptable depends on your income, your growth thesis and your tolerance for funding a shortfall. A buyer's agent models several interest rate scenarios so the decision is not built on today's rate alone. The Reserve Bank of Australia cash rate history shows how quickly holding costs can move.

A property can be financially sound and still be a trap. Physical due diligence is about what the building inspection and pest report reveal, and what they sometimes miss.

A standard building inspection covers the roof, walls, subfloor, wet areas, drainage and visible structural elements. A timber pest inspection looks for active termites, past termite damage, borers and fungal decay. In most of Australia these are ordered together. For an apartment, the inspection scope is narrower because common property is the strata corporation's responsibility, which makes the strata report the more important document.

The issues that should make you pause include:

• Movement cracking wider than two millimetres, especially stepped cracking through brickwork
• Rising damp or persistent moisture in subfloor timbers
• Evidence of past termite activity with no documented treatment
• Roof framing that has been altered without engineering sign off
• Illegal or unapproved structures such as a deck or granny flat built without a permit
• Polished concrete or render that hides recent patching

A buyer's agent does not perform the inspection themselves. They engage a licensed inspector, attend the inspection where possible, then translate the report into a decision. A report listing twelve items sounds alarming until someone explains that ten are routine maintenance and two are deal breakers. That triage is the value. The agent then uses material defects as negotiation leverage, either reducing the price or making the contract conditional on rectification.

Legal due diligence is the work your conveyancer or solicitor performs, coordinated by your buyer's agent so nothing is missed before the cooling off period ends or the auction hammer falls.

The title search confirms who owns the property and whether there are encumbrances. An easement may give a neighbour or a utility the right to run pipes or access a path across the land. A covenant may restrict what you can build. A caveat signals a third party claim. None of these are automatically fatal, but each one needs to be understood before you commit, because they can limit future development and resale appeal.

Zoning determines what the property can legally be used for and what could be built nearby. A site zoned for higher density may carry development upside. A neighbouring block zoned for a future road or a six storey building may erode your amenity. Buyer's agents check the planning overlays through the relevant state planning portal, such as the NSW Planning Portal.

For apartments and townhouses, the strata report is the single most revealing document. It shows:

Strata document	What it tells you
Administrative fund balance	Whether day to day running costs are covered
Capital works fund	Whether major repairs are funded or will trigger a special levy
Meeting minutes	Disputes, defects, planned works and building culture
Insurance certificate	Whether the building is adequately covered
By-laws	Restrictions on pets, renovations and short stays

A capital works fund of 9,000 dollars in a forty unit building is a warning sign. It usually means a special levy is coming, and that levy can run to tens of thousands of dollars per owner. Read our guide to buyer's agent fees in Australia to understand how this coordination is priced.

Market due diligence answers one question: is the asking price fair, and what should you actually pay. The tool for this is comparable sales analysis, often called comping.

A comparable sale is a property similar to the one you are buying that has sold recently in the same area. The closer the match on bedrooms, land size, condition, position and sale date, the more reliable the comparison. A buyer's agent assembles six to ten comparables, then adjusts each one for the differences. A comparable with a renovated kitchen and an extra bathroom is worth more than your target, so its sale price is adjusted down to estimate your property's value.

Recency matters because Australian markets move quickly. A sale from eight months ago in a rising market understates current value, while a sale from a falling quarter overstates it. Agents weight recent sales more heavily and watch the trend in the ABS residential property price indexes.

The danger is selective evidence. A selling agent will quote the three highest comparables to justify a price. A buyer's agent quotes the full set, including the sales that argue for a lower number, then builds a defensible range. For a property in Surry Hills or South Yarra, where stock turns over fast, the comparable set can be refreshed weekly. In a thinner market such as parts of Geelong, the agent may widen the search radius and rely more on land value. The output is a single sentence you can act on: this property is worth between X and Y, and anything above Y is overpaying. See our guide to negotiating a property purchase for how that range is then defended.

Due diligence is not one task. It is a sequence of checks, each with a specialist, and the buyer's agent is the project manager who keeps them in order and on time. Miss a step or run it too late and you either lose the property or lose your deposit.

The agent's role changes at each stage of the process:

1. Before you make an offer. The agent runs the market and financial analysis, orders the strata report for an apartment, and reviews zoning. This is desktop work that decides whether the property is worth pursuing at all.
2. Once your offer is accepted or before auction. The agent books the building and pest inspection, briefs the inspector on your specific concerns, and sends the contract to your conveyancer for the legal search.
3. During the cooling off period. The agent collects every report, triages the findings, and decides with you whether to proceed at the agreed price, renegotiate, or exit.
4. At settlement. The agent coordinates the final inspection to confirm the property is in the agreed condition and that nothing has been removed or damaged since exchange.

The reason this matters is timing. In a private treaty sale with a five day cooling off period, every report must be ordered, completed and reviewed inside that window. At auction there is no cooling off period at all, so all due diligence happens before you raise your hand. An experienced agent compresses the timeline by booking inspectors early and maintaining relationships that get reports turned around in two days rather than ten. Choosing the right agent for this is covered in how to choose a buyer's agent.

Most due diligence ends with a green light, sometimes a renegotiation. But it exists to catch the property that should never be bought. These are the findings that experienced buyer's agents treat as serious warnings.

A capital works fund that is nearly empty in an ageing strata building almost always means a special levy. A history of building defect litigation in the strata minutes can mean years of disputes and uninsurable risk. Active termites with structural damage can cost more to remediate than the discount you negotiate. An unapproved structure exposes you to council enforcement and may not be covered by insurance.

Beyond the building itself, watch for:

• A title with an easement that blocks the extension or subdivision your strategy depends on
• A purchase price that sits ten per cent or more above the comparable range with no clear reason
• A flood, bushfire or contamination overlay the selling agent did not disclose
• A rental appraisal from the selling agent that is well above genuine market rent, inflating the apparent yield
• A pattern of short hold periods in the building, which can signal a problem owners discover and then exit
• A body corporate dispute that has not been resolved

A red flag is not always a reason to walk. It is a reason to pause and price the risk. A 30,000 dollar special levy is a renegotiation, not a deal breaker, if the property is otherwise sound and the price reflects it. An undisclosed flood overlay in a high risk zone usually is a deal breaker. The buyer's agent's job is to know the difference, and to give you the evidence to make the call calmly rather than under auction pressure. For more on warning signs, read about buyer's agent red flags and how a good agent protects you.

If you want a vetted buyer's agent to run full due diligence on your next purchase, find a buyer's agent through Solva. It costs you nothing and takes about three minutes.