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When Is a Design Declaration Required Under the DBPA?

The NSW Design and Building Practitioners Act 2020 (DBPA) requires a registered design practitioner to lodge a design compliance declaration on the NSW Planning Portal for almost every regulated design that supports building work on a Class 2, 3 or 9c building. The question we get asked most often is: does my scope of work actually trigger a declaration? The short answer — if your work changes a "building element" on a relevant class of building, it does.

What the DBPA Defines as a "Building Element"

Under section 5 of the Design and Building Practitioners Regulation 2021, a building element includes:

• Fire safety systems (active and passive)
• Waterproofing
• The load-bearing components of a building that are essential to its stability (including foundations)
• A building enclosure (external walls, windows, roofing, doors that form part of the enclosure)
• Service installations covered by the regulations (electrical, plumbing, mechanical where they are performance solutions)

If your design touches any of the above, the work is "regulated design" and a registered design practitioner must declare it.

Which Buildings Are Captured

The DBPA currently applies to Class 2 buildings (apartments), parts of buildings containing Class 2, and as of July 2023 it was extended to Class 3 (boarding houses, hostels) and Class 9c (aged care). The Act does not yet capture pure Class 1 (houses) or pure Class 5–8 work — but where mixed-use developments include any Class 2/3/9c part, the whole structure is generally treated as captured.

Common Scopes That Trigger a Declaration

• Re-waterproofing balconies, podiums or planter boxes — waterproofing is a listed building element. Even a single balcony retrofit on one unit in a Class 2 building requires a declared design.
• Replacing or modifying external cladding — building enclosure work.
• Wall removals or post-installed lintels — load-bearing structural change.
• Replacing windows or sliding doors in the external envelope — building enclosure.
• Performance Solutions — any A2G2 expert-judgement pathway requires a declared design regardless of the trade.

Common Scopes That Don't Trigger a Declaration

Cosmetic finishes that don't form part of the building enclosure (internal painting, non-wet-area tiling, joinery), minor internal partition work that isn't load-bearing, and replacement of non-regulated services usually fall outside the regulated design definition. If in doubt, ask early — the cost of an upfront review is trivial compared with retrofitting a declaration after work has started.

What a Declared Design Actually Costs You

The declaration itself isn't the cost driver — it's the engineering work that supports it. The design must be prepared by, or under the supervision of, a registered design practitioner, retained in records, and lodged before any "building work" starts. For most strata waterproofing and remedial projects we work on, that means a one-page design declaration backed by a properly documented specification, schedule of products, and detail set.