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Sheet 5 · NSW declarations

An engineer’s certificate and the NCC: design compliance declarations in NSW

In New South Wales, the document that vouches for a regulated design on a class 2, 3 or 9c building is a design compliance declaration: a declaration, in the form the regulations prescribe, as to whether the design “complies with the requirements of the Building Code of Australia”, whether it meets other requirements the regulations prescribe, whether other standards, codes or requirements were applied in preparing it, and any other matter the regulations prescribe (Design and Building Practitioners Act 2020, s 8(1)). Building Commission NSW says that without the declared designs a certifier requires, the certifier cannot issue a construction certificate or complying development certificate for the regulated work.

General information about NSW law, not legal or engineering advice. The official place to check is Building Commission NSW’s page on design practitioner obligations, last updated 8 September 2026.

Law
Design and Building Practitioners Act 2020, Part 2
Code
Building Code of Australia (NCC 2025 Volume One)
Lodged on
NSW Planning Portal
Checked
9 October 2026
Which designs

The designs that need a declaration

The Act calls them regulated designs: a design prepared for a building element for building work, a design prepared for a performance solution, or any other design of a class the regulations prescribe (s 5(1)). Section 6 lists the building elements in full:

  • fire safety systems, in the Building Code of Australia’s sense of the term;
  • waterproofing;
  • an internal or external load-bearing component essential to the building’s stability, or to part of it, such as foundations and footings, floors, walls, roofs, columns and beams;
  • a component that is part of the building enclosure;
  • the parts of a building’s mechanical, plumbing and electrical services needed to comply with the Building Code of Australia;
  • other things the regulations prescribe.

Building Commission NSW says the regulated buildings are “currently class 2, 3 or 9c buildings, including mixed-use buildings”, and that regulated designs are required for all parts of a building that has a regulated part, such as a mixed-use building with offices (class 5) and residences (class 2). The page dates the reach by building class:

  • Class 2: new and existing building work.
  • Class 3 and 9c, new building work: from 3 July 2023.
  • Class 3 and 9c, alteration or renovation of existing buildings: from 1 July 2028.
The code

Where the NCC comes in

The code a declaration answers to is the Building Code of Australia. The National Construction Code’s online edition titles its first volume “NCC 2025 Volume One - Building Code of Australia Class 2 to 9 buildings”. Building Commission NSW defines a performance solution as “a method of complying with the Performance requirements set out in the Building Code of Australia, other than by a Deemed-to-Satisfy Solution”.

Part C3 of Volume One, for example, “contains Deemed-to-Satisfy Provisions for Part C1”, and one of them, C3D15, says: “In a Class 2 or 3 building, a public corridor, if more than 40 m in length, must be divided at intervals of not more than 40 m with smoke-proof walls complying with S11C2.” A design that meets the Performance requirements another way is a performance solution, and the Act counts a design for one as a regulated design.

Who signs

Who may make the declaration

A person must not make a design compliance declaration unless they are a registered design practitioner whose registration authorises a declaration on those matters. The maximum penalty is 1,500 penalty units for a body corporate, or 500 penalty units in any other case (s 10). Building Commission NSW says a professional engineer who wants to prepare regulated designs and make compliance declarations has to register as a design practitioner in the relevant class as well.

Building Commission NSW says only the person who declares or lodges needs to register as a design practitioner; one designer might sign off designs prepared by a team. Whether an engineer on that team must be registered as a professional engineer is covered on design and building practitioners in NSW. For work involving shoring, underpinning or anchoring, the page says regulated designs must come from a registered design practitioner in structural engineering, or a design practitioner in geotechnical engineering.

The sequence

When declarations are made and lodged

  1. When a design is ready for building workA registered design practitioner must give a design compliance declaration with a regulated design they prepared, once it is in a form suitable for use for building work (s 9(1)). Building Commission NSW says this means construction-issued designs, “not shop drawings or other drafts”.
  2. Before building work startsRegulated designs must be lodged on the NSW Planning Portal before the building work they relate to can start; the building practitioner or an appointed appropriate practitioner lodges them. If there is a principal design practitioner, the building practitioner must give them 14 days’ written notice before work starts.
  3. When a design changesA varied design needs a further declaration: before work starts for any regulated design, and after work starts where the design relates to a building element or performance solution (s 9(2) and (3)). Each varied design and declaration is lodged within one day of the variation, and work may need to stop to meet that timeframe.
  4. Before the occupation certificateThe person applying for the occupation certificate must notify the building practitioner at least 14 days before applying. Then “only a registered building practitioner can make and lodge the building compliance declaration”.
The signature

What a declaration commits its maker to

  • Truth. A person must not make a design compliance declaration they know to be false or misleading in a material particular. The maximum penalty is 2,000 penalty units or imprisonment for 2 years, or both (s 9(7)).
  • Insurance. A registered design practitioner must not give a declaration or prepare a regulated design unless adequately insured for it. The maximum penalty is 300 penalty units for a body corporate, or 100 penalty units in any other case (s 11).
  • The title block. Building Commission NSW says every declared regulated design that is a drawing or design must carry the standard title block.
  • Records. Records must be kept for at least 10 years from the date building work is completed, even if the practitioner stops practising.

Some building work on a regulated building needs no compliance declaration. Building Commission NSW lists the kinds, among them putting an awning, blind or canopy over a window or door, and the maintenance of a component of a system for mechanical, plumbing or electrical services. Its full list, with a pointer to section 13 of the Regulation, is on the design practitioner obligations page.

The NSW Legislation version of the Act read for this guide, current from 10 June 2026, notes that it does not include amendments made by three Acts not yet commenced: the Building Legislation Amendment Act 2023 (Schedule 2.2), the Building (Approvals and Practitioners) Act 2026 and the Fair Trading and Building Legislation Amendment Act 2026. This guide has not read those Acts; check the current version on NSW Legislation before relying on it.

Which engineers must be registered in NSW at all is on design and building practitioners in NSW. For Queensland’s scheme, see registered professional engineers in Queensland; the full comparison is on the comparison table.