Frequently asked questions about Sydney building approvals.
Plain-English answers from a team that's been getting things approved for over a decade.
Approval pathways
DA vs CDC — what's the difference?
A CDC (Complying Development Certificate) is a pre-approved pathway under state planning policy — if your project meets the rules, a private certifier can issue the certificate in around 21 days. A DA (Development Application) goes to your local council, gets assessed against the LEP and DCP, and takes longer because there is more discretion in the call. Same end goal, different path.
How long does each one take?
A CDC is typically issued within 21 days of lodgement, sometimes faster. A standard residential DA is 6–12 weeks once lodged in most Sydney councils, though heritage areas, flood zones or contested neighbours can push that out. Our DA vs CDC checker gives you an indicative timeline for your specific project in 90 seconds.
Can I switch from DA to CDC partway through?
Sometimes. If your design has been adjusted to meet the SEPP rules and your block qualifies, you can withdraw a DA and lodge a fresh CDC instead — or vice versa. We work out which path fits at the site visit so you don't usually need to switch later.
What happens if my CDC application is rejected?
A CDC isn't really 'rejected' the way a DA is — if your project doesn't meet the rules, the certifier won't issue the certificate. The fix is either to redesign so it does qualify, or to lodge a DA instead. Because we check eligibility before any drawings get done, we don't end up in this situation in practice.
Costs and fees
What does design and approval cost?
It depends on the project type and complexity. A granny flat through CDC sits at the lower end. A custom knockdown rebuild or a duplex with subdivision sits higher. We quote a fixed fee at the free site visit so you know exactly what design, engineering and approval will cost before you commit a cent.
Are council fees included in your quote?
Council lodgement fees and certifier fees are passed through at cost — they vary by council and project type, and they sit outside our design fee. We give you a clear estimate of those at the site visit so the total project cost is on one page, not split across surprise invoices.
Do you charge by the hour?
No. Every job is fixed fee. You know what design, engineering and approval will cost on day one. If the scope changes part-way through (you decide to add a pool, for example), we re-quote in writing — never an hourly creep.
What's the cheapest way to get a granny flat approved?
Where your block qualifies under the SEPP, the CDC pathway through a private certifier is almost always the fastest and cheapest route — typically 21 days to a certificate. If your block falls outside the SEPP rules, a DA is the only option, and we are honest about that at the site visit.
Process and timing
How long from first call to approval?
For a CDC granny flat, 4–8 weeks total — site visit, survey, design, lodgement and certificate. For a DA duplex or rebuild, 4–6 months end to end is typical. We give you a project-specific timeline at the site visit so you can plan around it.
Do you handle the certifier?
Yes. Lodgement, responding to RFIs, organising private certification — all included in our fixed fee. You don't ring the certifier directly. We do.
Can you work with my builder?
Yes. We are happy to sit in pre-construction meetings, answer your builder's RFIs during the build, and issue extra structural details on the fly. If you do not have a builder yet, we can suggest a few we have worked with successfully on similar projects.
What if council asks for changes?
Responding to council requests for information (RFIs) and re-lodging where needed is part of the fixed fee — not an extra invoice. We design knowing what each council typically pushes back on, which is why our approval rate has stayed at 100% for over a decade.
Specific project types
Can I subdivide my block?
It depends on your zoning, lot size and frontage. R3 and higher zones in most Sydney councils allow subdivision down to a minimum lot size; R2 generally does not. We confirm subdivision feasibility at the free site visit and include Torrens or strata drawings in scope when your block qualifies.
Do I need a town planner?
For most residential projects — granny flats, duplexes, rebuilds — no. We coordinate everything, including any planning argumentation council needs. Genuine town planning reports are rare for residential work outside contested overlays, and where one is required, we organise it as part of the fixed fee.
What's the difference between a duplex and a dual-occupancy?
"Duplex" is the everyday word. "Dual-occupancy" is the planning term in most LEPs. They mean two dwellings on the one lot — attached or detached. Whether yours is approvable as one or the other comes down to your zoning and your council's definitions, which we sort at the feasibility stage.
Can I build a granny flat on a battle-axe block?
Often, yes — but battle-axe blocks have specific rules around access width, the position of the secondary dwelling, and stormwater discharge. We have approved granny flats on plenty of battle-axe blocks across Sydney. The site visit tells us straight whether yours stacks up.
About Nemco
Where are you based?
Bankstown — Level 2, Suite 5/402–410 Chapel Rd. Architects, structural engineers, hydraulic engineers, drafters and certifier liaisons all in the one office.
What suburbs do you service?
Every Sydney metro council and most surrounding LGAs — Western Sydney, Sutherland Shire, Northern Beaches, Inner West, South Sydney and Greater Western Sydney. Tell us your suburb and we will confirm.
Are you licensed structural engineers?
Yes. Our structural engineers are NSW-registered and our reports are accepted by Sydney councils, certifiers, conveyancers and insurers. Every report is signed by a registered engineer — not handed off to a junior and rubber-stamped.
Are you registered with the NSW Architects Registration Board?
Yes. Our architectural design work is delivered by NARB-registered architects and qualified building designers, working alongside our in-house engineering and drafting team.
Start here
Get a free site visit this week.
A 30-minute walk-through with one of our designers. No charge, no obligation. You'll leave knowing exactly what's possible on your block, what it'll cost, and how long it'll take.
Sydney metro only. Site visits typically available within 5 business days.