On a live Class 2 apartment site in NSW, design changes are normal — but under the Design and Building Practitioners Act 2020 (DBP Act), some variations are paperwork and others are hard stops. If the change touches a building element or a performance solution, a registered design practitioner must prepare and declare a new regulated design before the varied work can start. Get the pathway wrong and you risk stop-work, Planning Portal lodgement failures, and Building Commission NSW audit exposure.
What counts as a design variation after Class 2 building work starts?
Section 20 of the DBP Act separates post-commencement variations into two practical tracks. Variations that do not relate to a building element or performance solution are recorded by the registered building practitioner in a variation statement and lodged before an occupation certificate (OC) application. Variations that do relate to a building element or performance solution — or that introduce a new building element or performance solution — require a fresh regulated design and design compliance declaration from a registered design practitioner whose registration authorises that work.
NSW Government guidance is explicit: the building practitioner must obtain the varied regulated design and declaration before the varied building work starts, then lodge the construction-issued regulated design and declaration on the NSW Planning Portal within one day of commencing that varied work. That one-day window also gives an appointed principal design practitioner time to update the principal compliance declaration.
| Variation type | Who prepares / declares | When work may start | What gets lodged |
|---|---|---|---|
| Building element or performance solution change | Registered design practitioner (correct class) | Only after regulated design + design compliance declaration obtained | Varied/new regulated design + declaration within 1 day of commencing varied work |
| New building element or performance solution introduced mid-build | Registered design practitioner | Same — design and declaration first | New regulated design + declaration on Planning Portal |
| Change unrelated to building element / performance solution | Building practitioner records variation statement | Per site controls; no new design declaration under DBP for that variation | Variation statement before OC application |
Primary sources: Design and Building Practitioners Act 2020 (s20); Building practitioner obligations; Design practitioner obligations.
Which building elements trigger a new regulated design on Class 2 projects?
Under the DBP Act, a regulated design is a design relating to a building element or the development of a performance solution for a regulated building. Class 2 residential flat buildings (and buildings with a Class 2 part, including mixed-use) are fully regulated. In practice, mid-build changes to structure, fire safety systems, waterproofing, façades, mechanical/smoke systems, vertical transportation integration, and other declared building elements almost always need a new design compliance declaration — not a variation statement alone.
Building practitioners should consult the relevant registered design practitioner before classifying a site instruction. NSW guidance states that practitioners should check whether a proposed change impacts a building element or performance solution; treating a structural, waterproofing, or fire-related change as a “minor site tweak” is a common compliance failure on apartment projects.
How do builders and RDPs sequence a mid-build variation without stopping the wrong work?
A workable Class 2 variation workflow looks like this:
- Freeze the affected zone only. Stop work that depends on the changed element; keep unrelated packages moving where safe and contractually allowed.
- Classify the change. Building practitioner + design practitioner decide: building element / performance solution, new element, or non-element variation.
- Issue construction-issued regulated design. The registered design practitioner prepares a construction-issued regulated design (with mandatory standard title block) suitable for building work — not a sketch or shop drawing alone.
- Make a new design compliance declaration. A separate declaration is required for each regulated design (including each variation to a building element or performance solution).
- Obtain documents before restart. Varied work must not start until the building practitioner has the design and declaration.
- Lodge within one day of commencing varied work. Building practitioner or nominated appropriate practitioner uploads to the NSW Planning Portal.
- Update principal compliance declaration if appointed. Where a principal design practitioner is on the project, include the varied design in the principal compliance declaration pathway.
Planning Portal lodgement steps for variations are documented in NSW Planning’s practitioner guidance (including upload of construction-issued regulated design variations after initial lodgement). See also the Planning Portal training resources linked from the building practitioner obligations page.
What is the principal design practitioner’s role when variations keep coming?
The principal design practitioner (PDP) role is optional but designed for larger Class 2 projects with high design volumes. Where appointed, the PDP coordinates and collects design compliance declarations, verifies they were prepared by registered practitioners in the right competency class, and makes principal compliance declarations. On variation-heavy apartment builds, appointing a PDP reduces the risk that a late package or mid-build façade/fire change slips through without a matching declaration.
NSW notes that not every design practitioner class can register as a PDP (for example, building design low-rise / medium-rise, drainage restricted, and vertical transportation classes are excluded). The building practitioner must give the PDP 14 days’ written notice before starting building work and before making a building compliance declaration ahead of OC, so principal declarations can be collated.
Variation statements vs new declarations — when is each enough?
A variation statement is the correct instrument for post-commencement changes that are not about a building element or performance solution. Clause 27 of the Design and Building Practitioners Regulation sets out what the statement must include. It cannot be used as a shortcut for waterproofing membrane changes, fire-stopping redesigns, structural member substitutions, or performance solution amendments — those need a new regulated design and design compliance declaration.
Before OC, the building practitioner typically lodges: building compliance declaration; contractor document; variation statements for non-element changes; any additional regulated design details that are not variations; evidence relating to temporary/removable encroaching ground anchors where relevant; and a principal compliance declaration if a PDP was appointed. After OC, further variations from what was lodged must still be uploaded within 90 days of OC issue.
Performance solutions mid-build: why Class 2 teams get caught
Performance solutions often emerge when a Deemed-to-Satisfy path fails on site — for example, fire separation details, acoustic pathing, or structural continuity around a late services clash. Under the DBP framework, developing or changing a performance solution for regulated building work is itself a trigger for regulated design and declaration. That means a site “workaround” that reframes compliance as a performance solution is not informal — it is a design event that must be declared before the varied work proceeds.
Coordination across disciplines matters: architectural, structural, fire safety engineering, façade, waterproofing, mechanical, and other registered classes must integrate designs. NSW design practitioner guidance stresses that designers must not work in isolation; poor integration is a major driver of variation cascades after construction starts.
Planning Portal timing risks developers and builders should budget for
Two timing rules drive programme risk on Class 2 apartments:
- No start of varied element work until design + declaration are in hand.
- Lodgement within one day after commencing that varied work.
If design capacity is thin, the one-day rule forces either a proactive RDP on retainer or deliberate stop-work on the affected package. Staged construction certificates add another layer: regulated designs and declarations for each certificate stage must be lodged before work under that certificate begins.
Building Commission NSW may audit designs lodged on the Planning Portal and the building work itself. Incomplete variation trails are a common audit finding when as-built conditions diverge from construction-issued regulated designs without matching declarations.
Practical checklist for developers, builders, and strata-bound Class 2 projects
| Checkpoint | Owner | Pass criteria |
|---|---|---|
| Register correct practitioner classes for building height/type | Developer / head contractor | RDP and building practitioner registrations match low-rise / medium-rise / general scope |
| Classify every site instruction | Building practitioner + RDP | Element / performance solution vs variation statement documented |
| Standard title block on every regulated drawing | Design practitioner | Mandatory title block present for Portal data extraction |
| One declaration per regulated design | Design practitioner | No batching multiple designs into a removed multi-design form |
| Obtain before restart; lodge within 1 day | Building / appropriate practitioner | Portal upload timestamps align with site diaries |
| PDP notice periods (if appointed) | Building practitioner | 14-day notices before start and before building compliance declaration |
| Pre-OC pack complete | Building practitioner | BCD, contractor document, variation statements, as-builts / final designs as required |
How giantA supports Class 2 variation control
giantA Pty Ltd provides NSW Registered Design Practitioner (Class 2) design documentation and compliance coordination for apartment developers, builders, and project teams. We prepare construction-issued regulated designs, design compliance declarations, and variation packages aligned to Planning Portal lodgement — so mid-build changes do not become undocumented defects for future owners corporations.
If your Class 2 project needs a variation review or RDP support for structural, architectural building design, or coordinated compliance declarations, contact giantA for a scoped engagement before the affected package restarts.
Frequently Asked Questions
Do all Class 2 site changes need a new design compliance declaration?
No. Only variations that relate to a building element or performance solution — or that introduce a new one — require a new regulated design and design compliance declaration. Other post-commencement variations are recorded by the building practitioner in a variation statement and lodged before the OC application.
Can varied Class 2 work start while the designer finishes drawings?
No for building-element or performance-solution variations. NSW guidance requires the building practitioner to obtain the regulated design and declaration before the varied building work commences. Lodgement on the Planning Portal then follows within one day of starting that varied work.
What is the one-day lodgement rule for Class 2 variations?
After the building practitioner obtains the varied regulated design and declaration and starts the varied work, the construction-issued regulated design and design compliance declaration for that variation must be lodged on the NSW Planning Portal within one day. This also supports principal design practitioner collation where a PDP is appointed.
Is a principal design practitioner mandatory on Class 2 apartments?
No. The PDP role is optional. It is commonly used on larger or more complex projects with high volumes of regulated designs. Where appointed, the PDP coordinates declarations and issues principal compliance declarations; the building practitioner remains responsible for lodging them.
Can a variation statement cover waterproofing or fire system changes?
No. Waterproofing, fire safety systems, and other building-element changes require a new regulated design and design compliance declaration. A variation statement must not be used for variations to building elements or performance solutions.
Who lodges variation documents on the NSW Planning Portal?
The registered building practitioner is responsible. They may nominate an appropriate practitioner (a registered design practitioner or principal design practitioner on the same project) to lodge designs and design compliance declarations, but only the building practitioner can make and lodge the building compliance declaration.
What happens after the occupation certificate if further variations appear?
Variations to building work beyond what was already lodged must be lodged on the NSW Planning Portal within 90 days of OC issue, including updated building compliance declaration material and related documents as applicable.
Does mixed-use with a Class 2 part follow the same variation rules?
Yes. Where a building includes a Class 2 (or other regulated) part, regulated design obligations apply to building work involving building elements or performance solutions across the relevant parts. Treat mixed-use podiums and residential towers as one regulated compliance system for variation control.
About the author: Franz Phan is a Registered Design Practitioner (Class 2) at giantA Pty Ltd, advising developers, builders, and project teams on NSW apartment design documentation and DBP Act compliance. giantA is a registered Design Practitioner under the Design and Building Practitioners scheme for Class 2 buildings.
This article is general information for NSW Class 2 projects and is not legal advice. Always confirm current requirements on nsw.gov.au, the NSW Planning Portal, and legislation.nsw.gov.au. Information checked against NSW Government practitioner guidance as of September 2026.