Mandatory inspection stages in Queensland

What it is

In Queensland, residential building work proceeds under a building approval issued by a private building certifier under the Building Act 1975 and the Building Regulation 2021. The certifier nominates the mandatory inspection stages for the project. Each stage is then inspected and signed off using the relevant statutory form before the next stage of work can be carried out.

For a Class 1a (detached dwelling) job in QLD, the standard mandatory inspection stages are:

• Footing inspection (before pouring footings)
• Slab inspection (before pouring the slab, with reinforcement and in-slab services in place)
• Frame inspection (after the structural frame is complete and before lining)
• Final inspection (when all work is complete)

QLD also uses pool fence inspections and waste disposal inspections for separable parts of the work where relevant.

Statutory forms

QLD has a defined form set under the Building Regulation 2021:

• Form 16 is the inspection certificate signed by a building certifier for a stage they have inspected directly
• Form 16 is also used by a competent person providing aspect inspection certificates that the building certifier relies on
• Form 21 is the final inspection certificate issued at completion. It is the document required before a Class 1a dwelling can be occupied

The building certifier collects each Form 16 across the project and uses it to support the Form 21. The Form 21 is the document the homeowner relies on and the document the QBCC asks for when a complaint hits a finished home.

Why it matters for compliance risk

The Building Act 1975 sets the certifier's duty to ensure each stage has been inspected before signing the next. The QBCC investigates certifier conduct under both the QBCC Act 1991 and a referral arrangement with the Department of Housing and Public Works. Two patterns trigger investigation:

• A Form 16 dated retrospectively after the work was covered
• A Form 21 issued without the supporting Form 16 record for an upstream stage

Footing and slab stages

These two stages must be inspected before any concrete is poured. The certifier checks the reinforcement layout, depth, cover and in-slab services against the engineering drawings. Once concrete is in, there is no way to verify the work.

Frame stage

Frame must be inspected before any wall or ceiling lining is installed. The certifier checks tie-downs, bracing, lintels, top and bottom plates and structural connections.

Final stage and Form 21

Final inspection covers waterproofing in wet areas, smoke alarms, balustrade height, glazing compliance and any conditions on the approval. A Form 21 will not issue if outstanding inspection records sit on the certifier's file.

Where TradeLens should flag risk

Audit triggers worth tracking on a QLD residential job:

• Form 16 dated later than the concrete pour or wall lining date
• Form 21 requested with one or more stage Form 16 entries missing
• Certifier swap mid-project where the new certifier has not re-issued or accepted the prior Form 16 records
• Aspect inspection by a competent person sitting on file without a matching Form 16
• Final approval condition (driveway, pool fence) closed out by builder declaration only without certifier sight