- Stage inspections check your new home before each stage gets covered up. Once the concrete’s poured or the plaster’s on, the evidence is gone.
- The main WA stages are pre-slab, slab, plate height, roof frame, lockup and PCI, with extra stages for double-storey homes.
- Each stage inspection is $399 + GST with a photo report within 24 hours.
- For a double brick home, pre-slab, plate height and roof frame protect most of the structure. On a two-storey home, don’t skip the suspended slab steel.
- Most WA contracts let you bring your own inspector on site with notice. Check the site access clause in your contract.
“I told Yahoo News I hadn’t seen a defect-free new build in five years. Stage inspections are how you find those defects while they’re still cheap to fix.”
Russell McCarthy, Registered Builder & Lead Building Inspector
Short answer: construction stage inspections are independent checks of your new home at key points during the build, before each stage gets covered up. In WA the main stages are pre-slab, slab, plate height, roof frame, lockup and practical completion, plus extra stages for double-storey homes. At WA Building Inspections each stage inspection is $399 + GST, with a photo report within 24 hours. Book each one as soon as your builder tells you the stage is ready.
Russell McCarthy here, registered builder (BP104751) and lead inspector at WA Building Inspections. When I spoke to Yahoo News this year, I said I hadn’t inspected a single defect-free new build in five years. Most of those defects were buried in the walls, slab or roof by the time anyone looked. Stage inspections are how you catch them while they’re still cheap to fix.
| Stage | When | Key checks | Price |
|---|---|---|---|
| Pre-slab | Before the concrete pour | Footings, set-out, reinforcement, vapour barrier, termite management | $399 + GST |
| Slab | After the pour | Dimensions, levels, edges, cracking | $399 + GST |
| Plate height | Brickwork at ceiling height | Wall ties, damp-proof course, weep holes, lintels (AS 3700) | $399 + GST |
| Double-storey stages | Suspended slab and first floor | Reinforcement, suspended slab, upper brickwork and roof frame | $399 + GST each |
| Roof frame | Frame up, before the roof cover | Trusses, bracing, tie-downs (AS 1684) | $399 + GST |
| Lockup | Roof on, windows and doors in | Roof cover, flashings, windows, wet area waterproofing (AS 3740) | $399 + GST |
| Practical completion (PCI) | Before handover | The whole finished home | $499 + GST |
Why stage inspections matter in WA
WA doesn’t have independent inspections at each stage of a house build. The site supervisor works for the builder. So unless you bring in your own inspector, nobody independent is checking the work as it goes up.
Most Perth homes are double brick on a concrete slab. That means the slab, the brickwork at plate height and the roof frame are where the big, expensive defects hide. Get those three right and you’ve protected most of the structure.
“The site supervisor works for the builder. Your inspector works for you. That’s the whole difference.”
Russell McCarthy
The stages, one by one
Stage 1: Pre-slab
Before the concrete is poured. We check site preparation, footings, slab set-out, plumbing penetrations, the vapour barrier, the reinforcement and the termite management system at the slab. Once the concrete is down, you can’t see any of it again.
Stage 2: Slab
After the pour. We check the slab’s dimensions, levels, edges and finish, and look for cracking and any damage to penetrations.
Stage 3: Plate height
When the brickwork reaches ceiling height. We check brickwork against AS 3700 and the NCC: wall ties, damp-proof courses, weep holes, lintels, openings and mortar joints.
Stages 4 to 7: Double-storey stages
Double-storey homes add the suspended slab steel, the suspended slab, the first-floor plate height and the first-floor roof frame. The suspended slab steel inspection is one of the most important on a two-storey home, because the reinforcement is checked against the engineer’s drawings before it’s buried.
Stage 8: Roof frame
Once the roof frame is up. We check the trusses or pitched frame against the design and AS 1684, including bracing, tie-downs, connections and any damaged or cut members.
Stage 9: Lockup
When the roof is on and the windows and external doors are in. We check the roof cover, flashings, windows and door installation, and waterproofing in the wet areas to AS 3740 before it’s tiled over.
Stage 10: Practical completion (PCI)
The final check before handover. It’s a full inspection of the finished home, giving you a written defects list for the builder.
When to book each stage
Ask your site supervisor to let you know a few days before each stage is ready. Most WA building contracts let you bring in your own inspector, as long as you give the builder notice and follow site safety rules. Check the site access clause in your contract first.
Timing matters most at pre-slab. The concrete truck doesn’t wait. If the builder pours before we’ve inspected, that stage is gone for good.
What do stage inspections cost?
Each stage inspection is $399 + GST, fixed, with a photo report within 24 hours. Here’s what a typical single-storey build looks like:
- Pre-slab, slab, plate height, roof frame and lockup: five stages at $399 + GST each, which is $1,995 + GST.
- Plus a PCI at handover: $499 + GST.
- Total: $2,494 + GST for the full build.
If you’ve had stage inspections with us, the standard PCI is all you need at handover. If you haven’t, book the Advanced PCI at $999 + GST. It adds a drone roof check, thermal imaging of the ceiling insulation, a shower leak test and a check against your plans.
Caught at plate height
I’ll call them the Rossis, and I’ve changed the details. Single-storey double brick build in Perth’s northern growth corridor, and they’d booked us for pre-slab, plate height and roof frame.
At plate height we found wall ties missing along a section of the cavity wall and weep holes sitting below the finished paving level. Both were fixed in a morning while the bricklayers were still on site.
Found after handover, the same problems would have meant rendered walls opened up, a dispute, and months of back and forth.
What happens when we find a defect?
You get the report with photos, the relevant clause of the NCC or Australian Standard, and a plain-English explanation. Send it to your site supervisor in writing and ask when it’ll be fixed. At the next stage we check that it’s been fixed.
If the builder won’t fix it, the report becomes your evidence. Most issues get sorted at this point. If they don’t, Building and Energy is the next step, and we can prepare an expert witness report if it goes further.
Frequently asked questions
What are the stages of a house build in WA?
The main inspection stages for a WA home are pre-slab, slab, plate height, roof frame, lockup and practical completion. Double-storey homes add suspended slab steel, suspended slab, first-floor plate height and first-floor roof frame.
How much does a construction stage inspection cost in Perth?
A construction stage inspection with WA Building Inspections is $399 + GST per stage, with a photo report within 24 hours. A typical single-storey build with five stage inspections and a PCI comes to about $2,494 + GST.
Which construction stage inspections are most important?
For a typical Perth double brick home, the pre-slab, plate height and roof frame stages protect most of the structure. On a double-storey home, the suspended slab steel inspection is critical. The PCI at the end is essential for every build.
Can my builder stop me from getting an independent inspection?
Most WA building contracts allow owners to bring an independent inspector on site with notice to the builder, subject to site safety rules. Check the site access clause in your contract and give your builder notice before each inspection.
Do I still need a PCI if I’ve had stage inspections?
Yes. Stage inspections check the structure as it goes up. The PCI checks the finished home, including finishes, fittings, wet areas and appliances, before you take handover.
Related Reading
- Pre-slab pour inspection Perth
- Weep hole placement: why builders get it wrong
- Practical completion inspection checklist WA
- Building dispute expert witness Perth
Written by Russell McCarthy, Registered Builder (BP104751) and Lead Building Inspector at WA Building Inspections Perth.