25 Jul Why a 10.7 Planning Certificate (2) & (5) is Crucial for Duplex Development
If you’re planning a duplex in NSW, one of the first documents you’ll need to check is the 10.7 Planning Certificate (formerly Section 149). This document outlines the zoning, development controls, and planning rules affecting a property. But here’s where many people get caught out:
Most contracts for sale only include a 10.7(2) certificate, which provides basic zoning and permissible use information but does not include all the details needed to assess the true feasibility of a duplex project. For a complete picture, you also need the 10.7(5) certificate, which reveals additional constraints and planning overlays.
What’s the Difference Between 10.7(2) and 10.7(5)?
- 10.7(2) Certificate – Includes zoning, land use, and whether a duplex (dual occupancy) is generally permitted. It’s essential but limited.
- 10.7(5) Certificate – Provides additional information on matters like bushfire risk, flooding, heritage, foreshore building lines, and acid sulphate soils — all of which can add costs or restrict development.
Without the (5) component, you could assume a block is suitable for a duplex only to later discover significant constraints that impact design or require costly reports.
Why It Matters for Duplex Design
The combined 10.7(2) & (5) certificate provides a complete understanding of:
- Zoning and permissible uses – Whether a duplex is allowed under council rules.
- Hazards and overlays – Bushfire or flood-prone land, foreshore restrictions, and other issues that may rule out Complying Development (CDC) and force a DA process.
- Environmental or heritage listings – Potentially requiring extra approvals or design adjustments.
For example, a property near the coastline might be zoned for dual occupancy, but a foreshore building line noted in the 10.7(5) could prevent a CDC approval — adding time and complexity.
Why You Should Obtain Both Certificates Early
Many buyers make the mistake of relying solely on the 10.7(2) included in their purchase contract. This can result in unexpected costs, redesigns, or lengthy approval delays once full site constraints are discovered.
By obtaining both the 10.7(2) and 10.7(5) certificates before committing to a design (or even before purchasing a site), you can:
- Confirm whether a duplex is truly feasible on the block.
- Identify potential risks and additional reports required (e.g., bushfire or flood consultants).
- Ensure your design complies with all council and state planning codes from day one.
The Role of a Building Designer
An experienced building designer will start every duplex feasibility study with a full review of the 10.7(2) & (5) certificates and interpret how these apply to your site. This early due diligence prevents wasted effort and ensures your design aligns with both your vision and the regulatory framework.
Ready to Start Your Duplex Project?
At Sustainable by Design, we help families, investors, and small developers take the guesswork out of duplex development. We’ll guide you through the planning requirements starting with the critical 10.7 certificate and create a custom design that maximises your block’s potential.
Thinking about a duplex? Talk to us before you start designing or buying land. A simple review of your 10.7(2) & (5) could save you thousands.