I'm going to do something unusual for a building inspector.
I'm giving you my complete Pre-Plaster checklist — the same category-by-category framework I run through on every pre-plaster (lockup) inspection I do. The exact list I use on my iPad on site when I'm walking your home after the roof and windows are on, but BEFORE the plasterboard goes up.
Why? Because this is the last honest look you'll ever get at what's inside your walls. Every wire, every pipe, every batt of insulation, every square millimetre of sarking and flashing gets buried under plasterboard the moment the sheeting starts. Whatever's wrong at this point stays wrong — for the life of your home.
This is a long guide. Bookmark it. Take it to site as soon as the plasterer is scheduled. If you spot 3+ items on this list wrong or missing — book an independent inspection before the wall linings go on.
📋 Free printable checklist: Download the Pre-Plaster (Lockup) Inspection checklist (PDF) — every red flag from this guide on a single page you can print and take on site. No email required.
What "Pre-Plaster" (Lockup) Actually Means
Pre-plaster — also called lockup stage — is the inspection window AFTER:
- Wall and roof frames complete and inspected
- Roof sheets or tiles installed (roof watertight)
- External windows and doors installed
- External wall cladding installed OR wall wrap (sarking) fully in place
- Electrical rough-in complete (all cables run — no fittings yet)
- Plumbing rough-in complete (all in-wall pipes and valves — no fixtures)
- Gas rough-in complete (if applicable)
- Air conditioning ducting installed (if ducted system)
But BEFORE:
- Wall and ceiling insulation batts installed
- Wet area waterproofing membrane goes down
- Plasterboard on walls
- Plasterboard on ceilings
- Any internal cladding or feature panels
- Skirting, architraves, cornices
- Kitchen and wet area cabinetry
Why the timing matters: the pre-plaster inspection must happen BEFORE insulation, BEFORE waterproofing, and BEFORE plaster. If you wait until any of those go in, you can no longer inspect the empty cavities, the framing behind wet area walls, or the service crossings. Once insulation fills the wall cavities you cannot properly see cable runs, pipe runs, or nogging positions.
Pre-plaster is your one-time-only chance to catch defects that will otherwise be hidden by plaster for 30-50 years.
Why the Pre-Plaster Inspection Matters (More Than You Think)
1. Services in the wrong place = ripping walls out later. A GPO 200mm off the plan, a plumbing rough-in for a mixer that lands 100mm off, a missing kitchen island conduit — invisible after insulation and plaster, expensive to fix once the tiler, plasterer and painter have all done their work.
2. Wall wrap + flashing defects = leaks that take years to appear. A torn wall wrap under a window, an unsealed penetration in the vapour barrier, a missed sill flashing — none of these are visible after plaster. They show up as mould, swollen skirting, and rotten framing in year 3-5.
3. Missing nail plates = a plasterer's screw gun through your services. Every cable, pipe or gas line crossing a stud face needs a galvanised nail plate over it. Miss one and the plasterboard fixer will drive a screw through the service at high speed — burst pipes, dead circuits, gas leaks. This is the single sneakiest defect at pre-plaster.
Standards That Apply at Pre-Plaster
- AS 4200.1:2017 — Pliable building membranes (product spec)
- AS 4200.2:2017 — Pliable building membranes (installation)
- AS 3740:2021 — Waterproofing of domestic wet areas (substrate readiness at this stage)
- AS/NZS 3500 series — Plumbing and drainage
- AS/NZS 3000 — Electrical installations (SAA Wiring Rules)
- AS/NZS 5601 — Gas installations
- AS 3660.1:2014 — Termite management (verify still intact and second-line)
- NCC Vol 2 Part 10 — Fire safety
- NCC Vol 2 Part 10.2 — Health and amenity (wet areas)
- QBCC Standards & Tolerances Guide — general workmanship
Important note: electrical rough-in must be signed off by a licensed electrician. Plumbing must be signed off by a licensed plumber. A building inspector reports on VISIBLE defects at these stages but does not certify compliance to AS/NZS 3000 or AS/NZS 3500 — that's the licensed trades' job. This checklist covers what YOU can see.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an InspectionThe 15-Category Framework I Use on Every Pre-Plaster Inspection
1. External Weatherproofing — Wall Wrap + Sarking (AS 4200.2)
The wall wrap (or sarking) is what keeps water out of your wall cavity while letting vapour escape. Once cladding and plaster are on, you can't inspect it. Now is the only time.
AS 4200.2:2017 installation requirements: - Horizontal laps: minimum 150mm - Vertical laps: minimum 150mm, positioned over a stud (not floating in a cavity) - All end laps fixed at a stud - All penetrations sealed — windows, joints, laps, service penetrations (this became mandatory in the 2017 revision) - If the membrane is designated a vapour barrier or air barrier, all joints, laps and penetrations must be taped
What to look for: - Continuous wrap around the whole building envelope — no gaps - Correct lap direction (upper sheet overlaps lower — like roof tiles) - All laps at least 150mm - All laps taped where required (per manufacturer and membrane class) - No visible tears, holes, or damage from tradies working around it - Wall wrap in place BEFORE cladding installed (not retrofitted around it) - Correct membrane class for your climate (vapour-permeable membranes for QLD humid climate — verify against manufacturer's spec)
Red flag: Vertical wall wrap laps floating in a stud cavity (not on a stud), OR any visible tears the size of a coin or larger that haven't been taped. Water will find every hole.
2. Window + Door Flashings
Every window and door is a hole in your weatherproofing. Flashings turn that hole back into a sealed edge.
AS 4200.2 window integration requirements: - Wall sarking cut over the opening at 45° from each corner - Sarking wrapped into the opening and taped onto the inside face of the framing - Sill flashing installed BEFORE the window goes in - Wall sarking lapping OVER the sill flashing upstand (not tucked behind) - Flashing tape along the bottom sill and up 200mm on each vertical face
What to look for: - Sill flashing visible at every window — running the full width, dressed up the sides - Head flashing at every window — visible above the frame OR clearly under the cladding - Sill drip — bottom edge kicked out (not tucked back against the wall) - Wall wrap dressed into the reveal and taped - No visible daylight around any window frame (feel with your hand on a windy day — no draft = sealed) - Flashing tape at penetrations for pipes, ducts, cables
Red flag: No sill flashing under a window OR wall wrap tucked BEHIND the sill flashing (should be OVER). This is one of the top-3 causes of window sill leaks in QLD new homes.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection3. Roof Watertightness (From Underneath)
You can't get on the roof at this stage. But you CAN check the underside — sarking under the tiles or sheets tells you a lot.
What to look for: - Roof sarking continuous across the whole roof plane - Laps a minimum of 150mm, correct direction (upper over lower) - Sarking dressed into gutters (drips outward, not back into cavity) - No visible daylight through the roof underlay when standing in the ceiling void with the internal lights off (a defect if any pinhole light visible) - Valley gutters visible from underside — no gaps at fold lines - Ridge line sarking sealed or lapped (check per roof designer's detail) - No damage from truss and batten installation (holes, tears)
Red flag: Daylight visible through roof underlay from inside the ceiling space. Rain will find that hole and drip into your insulation.
4. Electrical Rough-In (Visual Only — Licensed Sign-Off Required)
The electrician's job is to certify compliance to AS/NZS 3000. Your building inspector's job is to note what's visible and flag anything that looks wrong.
What to look for: - All cables in position for the switches, GPOs, lights on the electrical plan - No damaged cable sheathing (nicks, cuts, staple crushes) - Cables secured to studs — not floating in cavities - Cables that cross a stud face are protected with nail plates / stud protectors (galvanised steel plates that stop plasterboard fixers from driving screws through cables) - GPO and switch heights consistent (typically 300mm above floor for GPOs, 1200mm for switches — verify your spec) - Data / TV / comms cables in place per plan - Solar cabling stubbed out to inverter location (if solar planned) - Ceiling rose / batten holder positions match plan - Bathroom exhaust fan wired to correct switching - Correct RCD protection at the switchboard (electrician's job to confirm)
Red flag: Electrical cables crossing a stud face WITHOUT a nail plate over them. Plasterboard fixers drive dozens of screws into every wall — every unprotected cable is a fire waiting to happen.
5. Plumbing Rough-In (Visual Only — Licensed Sign-Off Required)
The plumber's job is to certify compliance to AS/NZS 3500. Your building inspector notes what's visible.
What to look for: - All plumbing rough-in stubs in position for every planned fixture (tap, mixer, shower, toilet, dishwasher, washing machine, ice-maker, outdoor tap) - Kitchen island water and waste stubs in position - Hot and cold water pipes correctly identified (typically red/blue markers or coloured lagging) - All copper joints look clean (no green oxidation = no wet joint) - All PEX / plastic pipe joints look properly crimped - No visible pipe damage (kinks in flexible connections, dents in copper) - Pipes secured to framing every 1200mm minimum (AS/NZS 3500) - Correct height set-out for mixers, taps (varies by fitting — verify your spec) - Pipes crossing stud faces protected with nail plates - Pipes not routed through structural members without engineer approval - Water hammer arrestors installed at washing machine and dishwasher rough-ins (per AS/NZS 3500)
Red flag: Plumbing pipes crossing a stud face without a nail plate. A screw through a copper pipe = burst pipe on day one.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection6. Gas Rough-In (If Applicable — Licensed Sign-Off Required)
Same principle as plumbing — visible only, licensed gas fitter certifies compliance.
What to look for: - Gas pipe routed per plan (typically copper or approved multi-layer) - Gas pipe pressure-tested (test pressure gauge should be on the pipe with a valid test record) - Bayonet fittings correctly positioned for cooktop, hot water, outdoor BBQ - Isolation valves accessible - Correct pipe sizing (per plumber's calculation) - Gas pipe protected at stud crossings with nail plates - Gas pipe not enclosed in wall cavity without approved ventilation per AS/NZS 5601
Red flag: Gas pipes buried behind plaster without a visible pressure test record, or gas pipes not protected at stud crossings.
7. Ducted Air Conditioning (If Applicable)
Ducted air conditioning goes in before insulation and plaster. You can see every duct run, every joint, every sag point.
What to look for: - Duct runs per air con design (check against plan) - All ducts insulated (typically foil-faced wrap) - Duct joints sealed with mastic or approved tape — no visible gaps - No sharp bends or crushed sections (reduces airflow permanently) - Refrigerant piping insulated and protected - Condensate drain lines installed with fall to outside - Zone motors and dampers accessible via ceiling access panel (planned) - Return air path clear (typically a large duct returning to the unit — no obstruction) - Outdoor unit location and mounting confirmed - Electrical connection to air con by licensed electrician
Red flag: Ducts with visible tears, crushed sections, or unsealed joints. Once the ceiling is on, you're cooling the roof space instead of your home.
8. Wet Area SUBSTRATE — Preparation for Waterproofing (AS 3740:2021)
Pre-plaster happens BEFORE the waterproofer arrives. So this category checks whether the wet area substrate is READY to receive waterproofing — not whether the membrane is already on. If the substrate is wrong, the waterproofing will fail no matter how well it's applied.
AS 3740:2021 background (what the waterproofer will need to comply with): - Shower area: full-height waterproofing to a minimum 1800mm above finished floor level OR 50mm above the shower rose (whichever is higher) - Whole wet area floor waterproofed (bathroom, laundry) - Minimum turn-up on walls at floor waste and shower waste per AS 3740 - Corners, joints, penetrations reinforced with bond breakers and tape - Membrane compatible with substrate (usually plasterboard rated for wet areas, or FC sheet) - Shower recess fall min. 1:100 WITH separation (hob/screen/step), 1:80 WITHOUT
What to look for at pre-plaster (substrate readiness): - Wet area floor and walls have the correct substrate specified (wet-area-rated plasterboard, or FC sheet, or fibre cement — depending on system) — verify against builder's waterproofing spec - All noggings behind future mixers, shower rails, tapware are in position (once membrane is on, you can't add these) - Shower set-down depth is correct (typically 70mm — verify from post-pour or your plans) - Floor fall to waste already screeded OR planned to be screeded before membrane - All wet area penetrations (drains, waste, mixers, taps) roughed in and accurately positioned per plan - Substrate flat and square — waterproofing needs a flat plane to bond to (verify with a 1.8m straight-edge) - No damaged substrate (torn plasterboard face, holes, chips) - Waterproofer's system data sheets on site and matched to substrate type - Certifier engaged and inspection booked BEFORE plaster starts
Red flag: Wet area substrate that is NOT wet-area-rated (using standard plasterboard where a wet-area board or FC sheet is required), OR a shower recess without the correct set-down depth, OR a floor waste not stubbed in the correct position. All of these will cause the waterproofing to fail or the tiler to lose their mind.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection9. Fire Ratings + Acoustic Separations
Party walls between attached dwellings, walls separating garages from living areas, and walls separating stairways all have fire and acoustic requirements per NCC Vol 2.
What to look for (if applicable to your build): - Garage-to-house wall: fire-rated plasterboard (typically 13mm fire-rated or similar) — self-closing door between garage and house - Party wall (townhouse / duplex): fire and acoustic rating per NCC — usually double-stud or offset-stud walls with acoustic batts and double-layer plasterboard both sides - Bedroom-to-living acoustic wall (if specified): acoustic batts and resilient mount channels - Under-stair fire separation: fire-rated lining if the stair is enclosed
Red flag: Standard plasterboard planned for the garage-to-house wall when NCC requires fire-rated. Or gaps in acoustic batts on party walls.
10. Termite Penetration Seals + Second-Line
Termite management doesn't stop at the slab. Pipe penetrations through the slab need second-line barriers, and any new penetrations added since pre-pour need to be sealed.
What to look for: - Every pipe penetration through the slab has a visible termite collar (Kordon collar or similar) - Any new post-pour penetrations sealed with an approved termite-compliant sealant - 75mm inspection zone around the slab perimeter still clear and visible - No landscaping or paving over the termite barrier - Termite management sign-off certificate on site (from pre-pour, still valid) - Perimeter reticulation system (if used) is accessible and tested
Red flag: New penetrations (added since pre-pour by plumbers or electricians) with no visible termite seal. Also: 75mm inspection zone already covered by landscaping.
11. Nail Plates / Stud Protectors on Every Service Crossing
I've mentioned this in Categories 4, 5 and 6, but it deserves its own category because it's so consistently missed.
Why nail plates matter: plasterboard fixers use collated screw guns to drive dozens of screws per sheet at high speed. Any cable, pipe, or gas line that crosses a stud face WITHOUT a nail plate has a very high chance of getting a screw driven through it. The plate is a galvanised steel plate with prongs that pushes onto the stud face, covering the service.
What to look for: - Every electrical cable crossing a stud face is covered by a nail plate - Every water pipe crossing a stud face is covered by a nail plate - Every gas pipe crossing a stud face is covered by a nail plate - Plates positioned so plaster screws hit the plate — not miss it - Plates flush to the stud face (not sitting proud)
Red flag: Any service crossing a stud face without a plate. Walk the whole home before plaster and tick every crossing.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection12. Backing Blocks + Noggings for Future Fixings
Every future fixing point — towel rail, TV bracket, kitchen cabinet, handrail, shower niche, mirror — needs solid backing behind the plaster. Nogging blocks are timber (or steel) blocks between studs at those heights.
What to look for: - Extra noggings behind every planned wall-hung fixture: - Kitchen wall cabinets (typically at 1500-2100mm heights) - Wall-mounted TV (verify heights) - Bathroom mixers, shower rails, shower niches, shampoo shelves - Towel rails, toilet roll holders - Handrails - Wall-hung vanity units - Nogging thickness sufficient to receive future screws (typically same section as stud) - Position marked on frame OR clearly identified from architectural drawings - Consistent height across similar walls (helps tradies later)
Red flag: Master bathroom with a shower niche planned but no noggings around the niche perimeter. Or a TV wall marked on plans with no backing block. Once plaster's on, adding backing means cutting the wall open.
13. Sound + Draught Sealing
Small gaps around services and wall penetrations become the sound and draught leaks in your finished home.
What to look for: - Bath spouts and shower arms: penetration sealed at the wall face - Air con penetrations through walls: sealed with mastic or foam - Downlight cutouts in ceiling planned and clearance detailed - External wall penetrations for services (refrigerant pipework, gas line, hose taps) sealed with approved sealant - Gaps between window frames and framing sealed with expanding foam or backing rod and sealant
Red flag: Large gaps around service penetrations left unsealed. Every gap is a draught, a sound leak, and a potential moisture entry.
14. Frame Level + Plumb — Second Check
The frame was checked at frame stage. But sometimes the wall linings crew ask for "adjustments" post-frame that push walls out of tolerance. QBCC tolerances still apply.
QBCC Standards & Tolerances Guide (reminder): - Wall out-of-plumb: max 4mm within any 2m height (AND compromises structure/water/safety) - Wall out-of-straight (bow): max 4mm in any 2m length within 12 months - Pre-plasterboard substrate: 1.8m straight-edge test — max 4mm over 90% of area, max 5mm over remaining 10%
What to look for: - Every wall re-checked with a 1.8m straight-edge (the strictest of the three tests) - Any packing / shimming added since frame stage is properly secured (not just wedged in) - Ceiling battens straight and evenly spaced (typically 450mm centres for plasterboard — verify manufacturer) - No twisted or damaged framing that will show through the plaster
Red flag: A wall that passed at frame stage but has since been damaged, twisted, or packed out of tolerance. The 1.8m substrate test is the strictest — any bow that fails it will telegraph through the finished plaster.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an Inspection15. Documentation On Site
Pre-plaster is a critical inspection point for documentation because so many trades have now done rough-in work that needs sign-off.
Must be on site: 1. Certificate of Compliance from licensed electrician for the electrical rough-in 2. Certificate of Compliance from licensed plumber for the plumbing rough-in 3. Gas certificate from licensed gas fitter (if gas installed) 4. Air conditioning installation drawings from installer (if ducted system) 5. Frame plan + bracing plan + tie-down schedule (should still be on site from frame stage) 6. Truss layout drawing (still on site) 7. Termite management sign-off (from pre-pour, still valid) 8. Architectural + engineering drawings (current revision)
Red flag: Any missing certificate from a rough-in trade. Each licensed trade's certificate is the record that their work complies with its relevant standard — no certificate, no compliance.
The 30 Red Flags — If You See ANY of These, Call an Inspector Immediately
If any of these are present at pre-plaster, book an independent inspection before the plasterer starts:
1. Wall wrap vertical laps floating in a stud cavity (not on a stud) 2. Wall wrap or sarking tears larger than a coin, untaped 3. Wall wrap under sill flashing (should be over the upstand) 4. No visible sill flashing at any window 5. Daylight visible through roof underlay from inside ceiling space 6. Roof sarking damaged during batten install 7. Electrical cable crossing stud face with no nail plate 8. Damaged electrical cable sheathing 9. Damaged cable at a staple (staple driven through sheathing) 10. Plumbing pipe crossing stud face with no nail plate 11. Kitchen island water and waste stubs missing 12. Water hammer arrestor not installed at washer / dishwasher rough-in 13. Gas pipe without visible pressure test record 14. Gas pipe crossing stud face without nail plate 15. Gas isolation valve not accessible 16. Air con ducts with tears, crushed sections, or unsealed joints 17. Air con condensate drain not falling to outside 18. Wet area substrate not wet-area-rated (standard plasterboard where a wet-area board / FC is required) 19. Shower recess without correct set-down depth for waterproofing 20. Standard plasterboard planned for garage-to-house wall (needs fire-rated) 21. Self-closing door missing between garage and house 22. New (post-pour) pipe penetration with no termite seal 23. Landscaping already covering 75mm termite inspection zone 24. Missing backing block behind planned wall-hung fixture (TV, cabinet, mixer, shower niche) 25. Large unsealed gaps around service penetrations (sound and draught leaks) 26. Wall out-of-plumb greater than 4mm/2m height AND compromises structure/water/safety (QBCC) 27. Wall failing QBCC 1.8m straight-edge test (over 4mm across 90% or over 5mm across 10%) 28. Ceiling battens spaced incorrectly for plasterboard (typically 450mm centres) 29. Bathroom exhaust fan not wired to appropriate switch (moisture/health defect) 30. Missing Certificate of Compliance from any rough-in trade (electrician / plumber / gas fitter)
Any 3+ = call an inspector. Any 10+ = don't let the plasterer start until fixed.
When to Book a Professional Inspection
I've just given you my complete checklist. You could try to do this yourself. Some homeowners can.
But here's the reality of what a professional inspector brings to a pre-plaster inspection:
- Ability to spot missed nail plates on services — this is the #1 sneaky defect at this stage and homeowners consistently miss it
- Wet area substrate readiness check — verifying wet-area-rated board is on the walls, correct set-downs, correct falls, correct noggings before the waterproofer arrives
- Wall wrap continuity + flashing verification — 150mm laps, vertical laps on studs, sill flashing UNDER wrap not over
- Independence — I'm not your builder's mate. I won't tell you "she'll be right" when a wet-area wall is about to be plastered over the wrong substrate
- Independent report with photos — printed evidence for a QBCC dispute or warranty claim
- QBCC-licensed authority — my report carries weight
- Same-day delivery — you get the written report before you leave site
- Free 15-minute post-report call — I walk your builder or trades through the report to resolve issues fast
When to book: the day before the plasterer is scheduled to start. Not the day of. That gives 24 hours to have any issues corrected before the sheeting arrives.
Ready to book your inspection? A VG Inspect QBCC-licensed inspector attends every job.
Book an InspectionVG Inspect Pre-Plaster Pricing
- Standard home up to 220m²: $550 inc GST — same-day report
- Larger homes: custom quote — call 07 3180 8041
- Available: Monday–Friday across South East Queensland (Brisbane, Gold Coast, Sunshine Coast, Ipswich, Moreton Bay, Logan, Redlands, Scenic Rim)
Book your pre-plaster inspection: Call 07 3180 8041 or book online.
Where This Inspection Sits in Your Build
Independent stage inspections work best as a sequence — each one checks work that the next stage covers up for good. Here's the full pathway for a typical Queensland new-home build, and where the pre-plaster (lockup) inspection fits:
1. Pre-Pour Slab Inspection — before the concrete truck arrives 2. Post-Pour Slab Inspection — after the slab is poured and stripped 3. Frame Inspection — Timber Frame or Steel Frame, depending on how your home is built 4. Pre-Plaster (Lockup) Inspection — you're reading this now 5. Practical Completion (PCI) Inspection — before you release your final payment
Previous: ← Frame Inspection (Timber or Steel) — Next: Practical Completion (PCI) Inspection →
Booking the whole sequence with one independent inspector means every stage is checked against the last. Book your inspection or call 07 3180 8041.
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This checklist is general educational information based on AS 4200.1, AS 4200.2, AS 3740, AS/NZS 3500 series, AS/NZS 3000, AS/NZS 5601, AS 3660.1, NCC Vol 2 Part 10 and Part 10.2, and the QBCC Standards & Tolerances Guide. Electrical, plumbing and gas compliance certification is the responsibility of licensed tradespeople in those disciplines. Your specific site and engineered design are the primary references for your build. This guide is not a substitute for a licensed inspection or trade certification.