PERTHWhat a building inspection covers under AS 4349.1
What a WA pre-purchase building inspection covers under AS 4349.1: visual and non-invasive, readily accessible areas, the specific exclusions
People pay for a building inspection expecting it to catch everything, then are surprised to read that whole parts of the house were "not inspected". That is not the inspector cutting corners. It is the Australian Standard the inspection is built on, and understanding what it covers, and what it deliberately does not, is how you get real value from the report rather than false comfort.
The standard behind the report
A pre-purchase building inspection in WA is carried out to AS 4349.1, the Australian Standard for pre-purchase inspection of residential buildings. It sets out what an inspector assesses, how the report is structured, and, importantly, the limits. A timber pest inspection is a separate standard, AS 4349.3, which is why building and pest are two scopes, often done together but governed separately.
Visual, and non-invasive
The single most important thing to understand: the inspection is visual and non-invasive. The inspector assesses what can be seen, using tools that do not damage the property, a moisture meter, a torch, a ladder, sometimes a thermal camera. They do not drill holes, cut into walls, lift floor coverings, or move furniture and stored goods. If a defect is behind a wall, under a fixed floor, or inside a sealed cavity, a visual inspection cannot see it, and the report will say the area was not inspected and why.
This is not a weakness to hide; it is the defined scope. An inspector who claimed to have checked inside your walls without opening them would be misrepresenting what they did.
Readily accessible areas
The standard limits the inspection to areas that are safely and reasonably accessible. In practice that means spaces the inspector can reach without risk and without a struggle, the roof space where the manhole allows safe entry and there is room to move, the subfloor where the clearance permits, the roof exterior where it can be safely reached. Where access is blocked by insulation, stored items, low clearance, or a safety risk like a fragile ceiling, that area is recorded as not inspected, with the reason. This is exactly why the things that hide, batten connections, subfloor timber, roof penetrations, are only found when the inspector can physically get to them.
What the standard specifically excludes
AS 4349.1 lists things outside a building inspection's scope. It is not a compliance certificate: the standard states plainly that a report under it is not a certificate of compliance with any Act, regulation or by-law. It does not review documents — building plans, permits or council records are a separate check. It does not test services: electrical, gas, plumbing operation, air conditioning, smoke alarm function, pool filtration and the like are specialist work, not an inspector's. And on strata, it is limited to the lot and its immediate surrounds — common property is outside scope.
The site items it does cover are defined too: things like retaining walls above a set height, paths, driveways, and drainage and stormwater within a set distance of the building, inside the boundaries.
How to get value from it
Read the limitations, not just the defect list. When a report says the roof space was only partly accessible, that is telling you where the uncertainty is, and where a further look might be warranted. A good report is honest about what it could not see, and that honesty is worth more than a clean-looking report that quietly inspected nothing. Where the standard's scope stops and a specialist is warranted — a structural engineer, a licensed electrician, a plumber's drain camera — a good report says so.
That is the whole point of paying for a pre-purchase inspection: not a guarantee that nothing can ever go wrong, but an honest, standard-based account of the condition of what could be seen, and clear direction on what to check further before you commit.
What "visual and non-invasive" really rules in and out
The two words that define a building inspection more than any others are visual and non-invasive, and understanding what they mean is the key to getting value from the report and to not being disappointed by it. Visual means the inspector assesses what can be seen; non-invasive means they do not cut into, dismantle, or take apart any part of the building to see what is behind it. Together these define an inspection as a careful, expert examination of the building as it presents, not a forensic dismantling of it. The inspector reads what can be seen. An experienced eye infers a great deal from surface evidence, but they do not open walls, lift floor coverings, or take the building apart, and the report reflects that.
This is not a shortcoming to be apologised for; it is the nature of the service, and it is what makes a pre-purchase inspection possible at all, since no seller would permit a buyer's inspector to cut holes in the house. But it has real consequences for what the inspection can and cannot tell you, and an honest report is clear about them. Defects that are concealed behind finishes, inside walls, under floors, within the core of timber members, may not be visible, and where the evidence on the surface points to a concealed problem, the inspection's job is to identify that evidence and recommend the further, invasive investigation warranted, rather than to pretend to have seen what a non-invasive inspection cannot see.
What "readily accessible" excludes in a real house
The inspection covers the areas that are readily accessible, meaning the areas the inspector can reach safely without moving heavy obstructions, using anything other than ordinary means of access, or putting themselves at risk, and in a real, occupied house that qualification excludes more than buyers often expect. A roof space with no safe access, or a manhole too small to enter, or trusses too tight to move through, may not be entered, and the report will say so. A subfloor too low to crawl may be inaccessible. Wall surfaces hidden behind the owner's furniture in an occupied house are not seen, and in a furnished house that can put a significant proportion of the wall area out of view. Parts of the roof exterior may be unsafe to access depending on the pitch, height, and condition.
The important thing is not that these limits exist, they are inherent and unavoidable, but that the report is honest about them: where something could not be accessed, a good report says so and says why, rather than staying silent and leaving the buyer to assume it was inspected and found sound. A report that quietly omits the roof space it never entered is worse than one that clearly states the roof space was not accessed and explains the reason, because the buyer of the first report does not know what they do not know. Reading an inspection report well means paying as much attention to what it says could not be accessed as to what it found, because the inaccessible areas are where the uninspected risk lives.
How to actually get value from an inspection
Getting value from a building inspection is partly about understanding what it is and using it accordingly. Because the inspection is visual and non-invasive and limited to accessible areas, its great strength is in the hands of an experienced inspector who can read a great deal from surface evidence, get properly into the accessible roof and subfloor spaces where so much of the real story is, and separate the significant from the trivial so that the report actually helps a decision rather than burying it in a list. The value is not in a guarantee that the house is perfect, which no inspection can give, but in an expert, honest assessment of the building's condition, its significant defects, and the areas where a closer or specialist look is warranted.
The buyer who gets the most from an inspection is the one who understands this: who reads the report for its significant findings and its recommendations for further investigation, who pays attention to the noted limits and access restrictions, and who treats the inspection as expert guidance for their decision rather than as a warranty. Where the report recommends a specialist, an engineer for structural movement, a specific investigation for a concealed concern, following that recommendation is part of getting the value, because the inspection's job includes knowing the boundary of what it can determine and pointing beyond it. The value is real. Used that way, a building inspection is one of the most valuable few hundred dollars a buyer spends, because it turns a hopeful purchase into an informed one.
Common questions
What does a building inspection cover?
Under AS 4349.1 it is a visual, non-invasive assessment of the readily accessible areas of a property — the interior, roof space, subfloor, exterior and defined site items where they can be safely and reasonably reached. It reports major and minor defects and safety issues that are visible.
What is not covered by a building inspection?
AS 4349.1 excludes what cannot be seen without damage, and specifically: it is not a compliance certificate, does not review permits or plans, does not test electrical, gas, plumbing or pool services, and on strata is limited to the lot, not common property.
Why does the report say areas were 'not inspected'?
Because the inspection is limited to safely and reasonably accessible areas. Where access is blocked by insulation, stored items, low clearance or a safety risk, that area is recorded as not inspected with the reason — which is honest scope, not a shortcut.
This comes up on every pre-purchase building inspection and building & timber pest inspection we carry out.
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Sources
Read rather than recalled. Summarised here; the documents themselves are Crown copyright and are linked rather than reproduced.