Purchasing a property is one of the most significant financial decisions most people will ever make. Yet it's striking how many buyers focus intensely on price negotiations and interior aesthetics, only to gloss over the one document that could reveal whether their dream home conceals a structural nightmare: the building inspection report.
A professional building inspection is not just a formality. It is a forensic investigation of a property's condition — walls, roof, foundations, plumbing, electrics, and everything in between. Understanding what a good inspector looks for, and what the findings mean, puts you in a far stronger position as a buyer.
The Foundation & Structural Frame
Everything else rests on the bones of a building. The inspector's first priority is to assess whether the foundation and load-bearing structure are sound. Cracks in foundations, uneven floors, bowing walls, and sagging rooflines are all potential indicators of structural movement — some cosmetic, some serious.
In particular, look out for differential settlement, where one part of a structure has sunk more than another. This can cause doors and windows to stick, visible cracks that run diagonally from corners, and gaps between walls and ceilings. A reputable inspector will differentiate between historic movement that has stabilised and active, ongoing movement that warrants further investigation by a structural engineer.
Foundation cracks — width, pattern, and direction
Uneven or springy floors suggesting subfloor decay
Bowing, bulging, or leaning external walls
Sagging or deflected roof structure
Evidence of previous underpinning or repairs
Roof, Cladding & Drainage
The roof is a property's primary defence against the elements, and its condition has an outsized impact on everything below. Inspectors will look at the roofing material — whether tiles, corrugated iron, or membrane — for cracking, lifting, corrosion, or missing sections. Flashings around chimneys, skylights, and parapets are common failure points where water finds its way in.
External cladding — whether weatherboard, brick veneer, or fibre cement — should be examined for cracks, gaps, and signs of moisture ingress. Poor drainage and inadequate downpipe connections are frequently overlooked by buyers but can cause serious problems over time, including subfloor flooding and rising damp.
Roof covering condition — missing, cracked, or lifted material
Flashing integrity around penetrations and junctions
Gutters and downpipes: blockages, rust, or disconnections
Cladding condition — cracks, gaps, peeling paint, moisture damage
Site drainage — does water flow away from the building?
Moisture, Mould & Internal Condition
Water is a building's most persistent enemy, and its effects are often hidden behind paint and plasterboard. Inspectors use moisture metres to test walls and floors in bathrooms, kitchens, laundries, and anywhere near external walls. Staining, bubbling paint, musty odours, and soft or discoloured plasterboard are classic warning signs.
Mould growth — particularly black mould — can have serious health implications and is frequently associated with chronic moisture problems rather than a single incident. It is important to understand whether any mould present is surface-level and easily remediated, or symptomatic of a deeper issue such as a leaking pipe, inadequate ventilation, or condensation from poor insulation.
Moisture metre readings in wet areas and around windows
Mould presence — location, extent, and likely cause
Condition of bathroom and kitchen waterproofing
Evidence of past or present leaks from pipes or roof
Ventilation adequacy in bathrooms, laundries, and roof space
Plumbing & Electrical
While a building inspector is not a licensed plumber or electrician and cannot test every circuit or pipe in depth, they are trained to identify obvious defects and flag where specialist investigation is warranted. Outdated wiring — such as older rubber-insulated cables or ungrounded systems — can pose a fire risk and may require a full rewire. Inspectors will also check the switchboard for adequate circuit protection and any DIY electrical work that may be unsafe or non-compliant.
On the plumbing side, look for evidence of low water pressure, slow drainage, corroded pipework, and leaking joints. If the property has an older hot water system, factor in the cost of replacement. In some regions, the age and compliance of the hot water system is a specific requirement to check before settlement.
Age and condition of the switchboard and wiring
Presence of safety switches (RCDs) and smoke alarms
Visible signs of unauthorised or DIY electrical work
Water pressure and drainage performance
Hot water system age, condition, and compliance
Pipe material — copper, PVC, or ageing galvanised steel
Timber Pests & Termites
In many parts of Australia and New Zealand, a separate timber pest inspection is as essential as the building inspection itself. Termites — also known as white ants — can cause catastrophic structural damage that is invisible to the naked eye until significant deterioration has already occurred. They are drawn to moisture, timber in contact with soil, and undisturbed cavities.
Even in the absence of active termites, a good inspector will look for past termite activity, evidence of prior treatment, and conditions conducive to infestation — including poor subfloor ventilation, timber debris, and leaking pipes near the foundation. A chemical barrier or baiting system in place does not guarantee permanent protection and requires ongoing maintenance.
Active termite workings — mud tubes, damaged timber, frass
Past termite activity and any previous treatment records
Risk factors: moisture, timber-to-soil contact, concealed cavities
Wood rot and fungal decay in subfloor and framing
Validity and coverage of any existing pest management system
Consents, Additions & Safety
An often-overlooked but legally significant area of the inspection is whether alterations, additions, or outbuildings have been constructed with the appropriate building consents. An unapproved deck, sleepout, or garage conversion can create complications at the time of sale — and potentially impose liability on the buyer if remediation is later required by the local council.
Inspectors will also look at key safety features: the presence and location of smoke alarms, pool fencing compliance if relevant, balustrade heights, and stair geometry. These are not merely cosmetic concerns — non-compliant pool fencing in particular carries significant liability for property owners.
Any additions or alterations — consented or apparent DIY
Smoke alarm placement and operational condition
Pool or spa barrier compliance with current regulations
Balustrade and handrail height compliance
Retaining walls — condition, drainage, and consent status
Choosing the Right Inspector
Not all building inspectors are equal. In New Zealand, look for a member of the New Zealand Institute of Building Surveyors (NZIBS) or a Registered Building Surveyor. In Australia, seek out licensed inspectors who operate in accordance with the relevant Australian Standards (AS 4349.1 for residential buildings). Ask whether they carry professional indemnity insurance and request a sample report before engaging them.
Finally, read the report carefully and do not hesitate to call the inspector to discuss any findings you do not understand. A thorough inspection report is not a reason to walk away — it is leverage for an informed negotiation, or the reassurance that you need to proceed with confidence.
