Modifications (Section 4.55)
Changes to an already-approved DA without lodging a completely new application - faster and cheaper than fresh DA.
A Section 4.55 modification (also called s4.55 or mod) is a formal request to change an already-approved DA without starting from scratch. Under Section 4.55 of the Environmental Planning and Assessment Act, you can modify approved plans to fix errors, make design improvements, or respond to construction issues. Three types: s4.55(1) fixes errors/misdescriptions, s4.55(1A) for minimal environmental impact changes (quick, usually 2-4 weeks), and s4.55(2) for more substantial changes that maintain the development's character (slower, similar process to DA). Modifications are cheaper than new DAs (typically $1,000-$3,000 vs $5,000-$15,000) and faster. However, modifications can't fundamentally change the development - can't turn a single-storey approval into two-storey, or change from house to shop. If proposed changes are too significant, council will require new DA.
What does it mean for my project?
When you're planning work and 'Modifications (Section 4.55)' comes up in council advice, approval conditions or reports, understanding what it means helps you know what approvals, reports or design changes you might need. It can affect your design options, costs, timeframes and how council or a certifier assesses your project.
What do I need to think about?
If you're not sure how 'Modifications (Section 4.55)' applies to your block or project, check your council information or talk to a planner, certifier or other relevant specialist. Misunderstanding it can lead to delays, extra design fees or even having to redo work, so it's worth clarifying early in the planning stage.
Examples where it might impact a project
We got approval for the house but decided to change the window sizes, lodged a Section 4.55 modification instead of a new DA.
State specific stuff...
No state specific requirements - used across Australia (check your local council for any local variations).