Structural Certification And Inspection Certificates In NSW

At the end of every building job in NSW, someone asks the structural engineer for a certificate. The answer depends entirely on what happened during the job, because an engineer can only certify what they designed and what they saw.

That surprises people. They expect the certificate to be a form filled in at the end. In practice it is the last page of a record that starts at design and runs through every structural stage on site.

Who certifies what

The principal certifier is responsible for issuing the construction certificate before work starts and the occupation certificate before anyone moves in. The certifier also carries out the mandatory critical stage inspections set by the regulations.

The structural engineer does not replace the certifier. What the engineer provides is evidence the certifier relies on: that the structural design complies with the National Construction Code and the Australian Standards, and that the structure was built in accordance with that design.

On apartment buildings and other Class 2 work, there is a separate regime of registered practitioners and compliance declarations, covered in [NSW building compliance, what changed](/blog/nsw-building-compliance-what-changed) and [design practitioner registration in NSW](/blog/design-practitioner-registration-nsw). The principle underneath is the same on every project. Paperwork follows what was actually done.

At design

Before the construction certificate, the engineer certifies the structural design.

That certificate states which standards the design complies with, typically AS 1170 for loads, AS 3600 for concrete, AS 4100 for steel and AS 2870 or a geotechnical report for footings. It identifies the drawings by number and revision. A certificate that refers to revision B is no use when the builder is working from revision D, so every time the drawings change, the certification has to follow them.

During construction

This is the part that decides whether a final certificate can be issued at all.

The structural inspections that matter happen before things are covered up. Footing excavations before concrete. Reinforcement in every footing, slab, wall and column before each pour. Post-tensioning tendons before the pour and again at stressing. Steel connections and bolting. Timber framing and tie-down before the linings go on.

At each inspection the engineer checks the work against the drawings, notes anything that needs fixing, and confirms when it has been fixed. The result is an inspection record, with photos, for every stage. What the inspections look for on a concrete pour is set out in [construction supervision and the critical role of pre-pour inspections](/blog/construction-supervision-pre-pour-inspections).

The certificate at the end

For the occupation certificate, the certifier will usually ask for a final structural certificate stating that the structure has been constructed in accordance with the approved design.

The engineer can sign that certificate when the inspection records cover every structural stage. When they do, it is a straightforward letter. When they do not, it is a problem.

When a stage was missed

The most common reason a structural certificate cannot be issued is simple. A slab was poured before the engineer saw the steel.

Once concrete is in, the reinforcement cannot be inspected. The engineer has nothing to certify from, and no amount of good intention changes that. The options at that point are slow and expensive: scanning the slab to locate the steel, cutting cores, breaking out sections, or load testing. Sometimes the answer is fine. Sometimes it is not, and the slab has to be strengthened or replaced.

The same applies to changes made on site without the designer. A column moved to clear a service, a beam cut for a duct, a different product substituted. Each needs the engineer's review and an updated drawing before the work proceeds, as discussed in [who is responsible when a design changes on site](/blog/who-is-responsible-when-a-design-changes-on-site). An undocumented change is a change nobody can certify.

What helps the builder

The builder controls most of this, and three habits make certification painless.

Book inspections with enough notice, and do not pour until the engineer has signed off the steel. Keep the engineer informed of every change, before it is built. Hand over product certificates, concrete dockets and test results as the job goes, rather than hunting for them at the end.

How we approach it

We treat certification as part of the design service, not an extra at the end. We inspect every structural stage we are engaged for, keep the records with photos, and issue certificates that match the drawings actually used on site.

When the final certificate is a formality, it is because the work was checked at every stage before it was covered. That is the only way a structural certificate should be issued.

ACSES provides structural engineering and construction inspection across Sydney. Talk to us about a project.

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