Class 5 Office Building Design Sydney
Office buildings and commercial workplace design across Sydney. Standalone offices, tenancy fit-outs, medical suites with Section J energy compliance.
Contact UsOffice design scope
- Standalone office buildings (new construction)
- Office fit-outs in existing buildings
- Medical and dental suites
- Co-working spaces and business incubators
- Home-to-office conversions (change of use)
Costs and timeline
| Scale | Design fee | DA timeline |
|---|---|---|
| Small standalone (500 m²) | $50,000 – $120,000 | 4 – 6 months |
| Medium (2,000 m²) | $120,000 – $300,000 | 6 – 9 months |
| Tenancy fit-out | $3,000 – $8,000 per m² | CDC 2–4 weeks / DA 6–12 weeks |
Frequently Asked Questions
What is a Class 5 building?
Class 5 covers office buildings used for professional or commercial purposes. It includes standalone offices, office floors in mixed-use buildings, medical offices, and co-working spaces. Class 5 buildings need commercial-grade compliance: fire safety, disability access, hydraulic services and acoustic separation.
How much does office building design cost in Sydney?
Small office building (2–3 storeys, 500 m²): design fees $50,000–$120,000. Medium office (4–6 storeys, 2,000 m²): $120,000–$300,000. Fees typically 5–8% of construction cost. Fit-out design is separate ($3,000–$8,000 per m² of internal area).
Can I convert a house to an office?
Yes — but the change of use triggers commercial standards: disability access (ramps, accessible toilets), fire safety upgrades, and parking compliance. Zoning must permit office use (B1 Neighbourhood Business, B2 Local Centre, B4 Mixed Use, or SP zones). A change of use DA is required.
What BASIX and energy standards apply to offices?
Offices need Section J of the NCC (energy efficiency) compliance — more complex than BASIX. This includes facade thermal performance (U-values, glazing-to-wall ratios), artificial lighting power density, HVAC efficiency, and often solar PV and battery storage systems.
How long does office DA approval take?
Small office building: 4–6 months DA. Medium office in established commercial precinct: 6–9 months. Mixed-use projects with residential components: 9–12+ months. Pre-lodgement meetings significantly reduce timelines.
Do office buildings need a Registered Design Practitioner?
Small Class 5 office buildings alone do not require RDP sign-off under the DBP Act 2020 (which applies to Class 2, 3 and 9c). However, if the building has any Class 2, 3 or 9c component (mixed-use with apartments, hotel or aged care), the entire building becomes regulated. We advise on regulatory status at feasibility stage.
Ready to discuss your project?
Talk to our team about your site, timeline and approval pathway. We respond within one business day.
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