Shea CullenNSW Registered Architect 9748 · Updated 27 September 2026I get asked this every few weeks, usually by someone partway through a build with a project home builder, usually phrased apologetically, as though wanting a second set of eyes were a slight against the builder. It is not. It is the cheapest insurance in the entire project.
My answer is yes, and the reason is not distrust. It is timing.
The whole argument in one sentence
Every extra problem you find now is a problem the builder has to fix. Every problem you find later is a problem you have to fix.
While the work is open and the money is unpaid, a defect is a phone call and a morning of somebody else's labour. Once it is covered, the same defect is a demolition job, a dispute, and quite possibly a tribunal.
Chances are the inspector will spot problems worth more than you are paying them. If they do not, that is not a wasted fee, that is peace of mind you bought at a fair price, and it is worth having.
The mistake almost everyone makes: your certifier is not your inspector
This is the misunderstanding I correct most often, and it costs people real money.
Your principal certifier does visit the site. For a house, being a Class 1 or Class 10 building, clause 61 of the Environmental Planning and Assessment (Development Certification and Fire Safety) Regulation 2021 sets six mandatory critical stage inspections:
- After excavation and before the footings are placed.
- Before any in situ reinforced concrete building element is poured.
- Before the framework for any floor, wall or roof is covered.
- Before waterproofing in a wet area is covered.
- Before stormwater drainage connections are covered.
- After the work is complete, before an occupation certificate is issued.
Read that list and it sounds like everything is covered. It is not, because those inspections answer a narrow question: does the work comply with the approval and the Building Code at that moment. They are a statutory function, not a service you have engaged.
The law and the case law are both blunt about it. A certifier is not a clerk of works. They do not supervise the builder, they are not a site foreman, and they are not looking over anyone's shoulder on your behalf. They do not check that tiles are laid square, that the paint is applied properly, that the doors swing cleanly, or that any of the hundred things you will live with every day were done well. Your concerns about quality of construction are contractual, which means they sit between you and your builder, and nobody else is watching them.
There is also the awkward commercial fact underneath. On most project home builds, the builder chooses the certifier and the builder pays the certifier, and the same certifier will want the next hundred jobs from the same builder. I am not suggesting anything improper. I am pointing out that the one professional attending your site at the critical moments has no contract with you, no duty to your quality outcomes, and a commercial relationship with the other party. An independent inspector you engage and pay has exactly one client.
What an inspector actually finds
Here is a real example, a list one inspector picked up on a single prepour inspection, before a slab was poured on a new home. Four items:
The vapour barrier was not installed to AS 2870, the engineer's plans or the Code. The standard calls for a minimum 0.2 mm polyethylene membrane, sheets lapped at least 200 mm, turned up against the slab edge. Get it wrong and you have built a permanent moisture path into the ground floor of the house. The fix before the pour is a roll of plastic and an hour. The fix afterwards does not exist, because the membrane is under 100 mm of concrete for the life of the building. What you get instead is rising damp in the slab, flooring that lifts, and a defect claim that turns into an argument about whether anyone can prove what was down there.
Plumbing pipes were out of position against the plan. Cheap to move on a Tuesday morning. Expensive on Wednesday, once they are cast into the slab and the bathroom has to be redesigned around them or the concrete cut and patched.
No termite collars to the pipe penetrations. Slab penetrations are the classic termite entry point, which is why AS 3660.1 deals with them specifically, including the requirement to keep the collar clear of reinforcing mesh and bar chairs. Miss them and the termite management system has a hole in it from day one, and you will not know until something is eating your frame.
Insufficient concrete cover to the reinforcement in places. Cover is what keeps the steel from rusting. Rusting steel expands, expanding steel cracks concrete, and cracked concrete is spalling that turns up years later as a structural repair bill.
Four items, one visit, and every single one of them would have been invisible and unarguable within twenty four hours. That is why the inspections immediately before something gets covered matter more than all the others put together.
The maths
Independent stage inspections run about $300 to $600 each for a standard house, with full packages covering all the main stages usually somewhere between $1,400 and $2,200, because most inspectors discount when you book the set.
Now put that next to one missed vapour barrier. Or one frame with studs out of plumb beyond the 4 mm in any 2 m allowance, discovered after the plasterboard is on. Or one shower where the membrane was skipped up the wall behind the tiles.
On the apartment side, where somebody actually counts, Building Commission NSW research published in 2026 found 53% of surveyed strata buildings had a serious defect, with waterproofing the most common at 22%. Houses are simpler than apartments and nobody surveys them the same way, so I will not pretend that number transfers. But nothing about the way a house gets built makes it immune to the same causes, and the owner of a house has fewer people to share the cost with.
The second reason, which nobody puts in the brochure
A build that is being inspected gets built differently.
I am not being cynical about builders. Most of the ones I work with on the Central Coast are good and would rather be told about a problem while it is cheap. But every site has a bad week, a subcontractor who cut a corner, a supervisor stretched across nine jobs. When everyone on site knows an independent inspector is coming before the pour, the plastic gets lapped properly and the collars go on. That effect is free, and you get it the moment you tell the builder you have engaged an inspector.
Tell them early, and tell them plainly. Not as a threat, just as information: I am having each stage inspected before it is covered, here are the stages, please give me a few days' notice of each. A good builder will shrug. A builder who reacts badly to that sentence has told you something useful and you should read my list of red flags when choosing a builder.
Time the inspections to your progress payments
Your leverage in a building contract lives entirely in the money you have not paid yet, which is the same principle behind changing a project home contract before you sign it.
So book each inspection for before you release the progress claim for that stage, not after. The frame claim gets paid once the frame passes. It is astonishing how much faster a rectification happens when it sits between the builder and their money, and how slowly the same item moves once the invoice is settled.
Better still, write it into the contract before you sign. A short special condition naming your right to have an independent inspection at each stage, requiring reasonable notice from the builder before covering work, costs nothing at signing and is close to impossible to add later. It belongs on the same list as the rest of the questions to ask before signing a building contract in NSW.
Why "I will just claim on the warranty later" is a weak plan
Owners often assume the safety net makes the inspections optional. The safety net is real, and it is much worse than the inspection.
The statutory warranties in section 18B of the Home Building Act attach automatically to every residential building contract and cannot be signed away: due care and skill, in accordance with the plans and specifications, suitable materials, compliant with the law, fit to live in. They run 6 years from completion for a major defect and 2 years for everything else, and you have to give written notice within 6 months of the problem becoming apparent.
Then look at what enforcing them involves. You measure and document. You write to the builder. If that stalls, you complain to Building Commission NSW, which is free and generally gets an inspector out within a few weeks, and can end in a rectification order. If that fails, NCAT, where the case turns on competing expert reports and takes the better part of a year out of your life.
And the insurance behind it all, the Home Building Compensation Fund cover your builder has to hold on work over $20,000, is last resort cover. It does not pay because your builder is being difficult. It pays only if the builder has died, disappeared, become insolvent, or had their licence suspended for failing to comply with a court or tribunal order. A solvent, uncooperative builder is not a trigger.
Choosing an inspector, since anyone can call themselves one
This is where people get burnt, so be careful. Residential building inspection is unregulated in NSW. The Building Consultancy Licence was repealed on 16 September 2009 and nothing replaced it, so there is no licence to check and no register to search. NSW Fair Trading's own advice is to use a suitably qualified person such as a licensed builder, a surveyor or an architect.
What I would look for:
A real qualification. A building surveying or building and construction diploma, a current builder licence, or registration as an architect. A Certificate IV on its own is not enough for the job you are asking them to do.
Professional indemnity insurance, current, sighted. If their report is wrong you need somebody standing behind it. Ask for the certificate of currency, not a claim in an email.
A sample report. This tells you more than anything else. You want photographs, plain descriptions, and each item tied to a clause of the Code, an Australian Standard or the Guide to Standards and Tolerances. A report that says "vapour barrier not lapped in accordance with AS 2870, see photo 6" is evidence. A report that says "slab looked ok" is a receipt.
Genuine independence. They must have no relationship with your builder and no work coming from them. Ask directly.
Availability on short notice. Prepour and frame windows are measured in days, sometimes hours. An inspector who cannot get there in that window is no use, however good their report.
Being honest about the limits
Two things an independent inspector will not do for you.
They will not make an adversarial project pleasant. A report listing every scuff and paint run, fired at the builder as a complaint, burns goodwill you will need later for the items that actually matter. Send the report as information, sort it into what is defective against a published figure and what is cosmetic, and stay calm. The point is a good house, not a won argument.
And they cannot check the build against documents that do not say anything. An inspector compares what has been built to what was specified, so when the specification is a page of allowances and generic notes, there is very little to hold the work against, and "within tolerance" fills every silence.
Where I fit
I am an architect, not a building inspector, and I am not trying to sell you one. Engage a good independent inspector, and if you want a name for one on the Central Coast, ask me and I will point you at someone.
What I do is the half of this that has to happen earlier. Drawings and specifications detailed enough that there is a clear right answer to check the work against, so an inspector's visit produces findings rather than opinions.
If you are about to build, the place to start is before you build on the Central Coast, and the free site assessment at /start if you want to talk about a specific project.