FAQs

In NSW, a secondary dwelling and a granny flat are the same thing. The term “secondary dwelling” is the official planning term used in the NSW Government’s Housing State Environmental Planning Policy (SEPP). It simply refers to the second, smaller dwelling on the same residential lot as the principal (main) dwelling.

Yes — renting out a granny flat is one of the most common reasons people build them. You enter into a separate residential tenancy agreement for the granny flat under the NSW Residential Tenancies Act, completely independently of any tenancy in the main house. The rental income is yours to keep (and is taxable income, so speak to your accountant).

Generally yes — a fully compliant, well-built granny flat with an occupation certificate adds genuine value to your property. The extent of the uplift depends on location, the quality of the build, and buyer demand in your area. Many valuers and banks treat a secondary dwelling as a positive feature when assessing property value.

A Complying Development Certificate (CDC) is a fast-track planning and construction approval issued by a private accredited certifier (not your local council). Under NSW’s Housing SEPP, granny flats that meet the prescribed standards can be approved via CDC in approximately 30 days once lodged— compared to 3–6+ months for a council Development Application (DA).

At Granny Flats Illawarra, we specialise exclusively in CDC approvals — meaning faster, more predictable timelines for our clients. Learn more about CDC approvals.

CDC (Complying Development Certificate): State government pathway. Assessed by a private certifier. Typically 30 days once lodged. Outcome is certain if criteria are met. GFI uses this pathway exclusively.

DA (Development Application): Council pathway. Assessed by local government. Can take 3–6+ months. Outcome less certain. Subject to neighbour objections and council discretion.

For granny flats that meet the CDC criteria, there is no reason to use the DA pathway. GFI ensures our designs always qualify for CDC.

Under NSW CDC rules, a granny flat can be a maximum of 60m² of internal floor area (excluding decks, balconies, and verandahs). There is no minimum size specified, but practical self-containment typically requires at least 25m² for a studio.

Yes — you can build a granny flat while a tenant occupies the main house. The key is structuring the construction carefully: we advise on fencing the construction zone, ensuring the existing lease clearly excludes the granny flat site, and minimising disruption to your tenant. Protecting your existing rental income during construction is something we take seriously for every investor client.

Our fixed-design approach means we offer a curated range rather than fully open-ended custom builds. This intentional approach is what allows us to deliver speed, CDC certainty, and fixed pricing. Within our range, there are options for different layouts, sizes, and finish levels. At your free site inspection, we’ll show you what fits your block and your goals.

The typical timeline from first enquiry to handover is approximately 5–6 months:

• 📋 Site inspection to Pre-Construction Contract: 1–2 weeks
• ✅ CDC approval: approximately 30 days once lodged
• 📝 Construction contract and build start scheduling: 1–2 weeks
• 🔨 Construction: approximately 10–14 weeks
• 🗝️ Final inspection and handover: 1 week

Building costs in the Illawarra typically range from $100,000 for a compact studio to $280,000 for a larger 2 bedroom build, depending on site conditions, size, and finish level. Our fixed-design approach means pricing is clear and inclusive — no open-ended quotes that blow out during construction. We provide firm pricing after your site inspection.

Our fixed pricing is fully inclusive and covers: site preparation, slab and footings, structural frame, roofing and cladding, windows and doors, internal fit-out (kitchen, bathroom, flooring, painting, lighting, air conditioning), all services connections (water, sewer, electrical), external works (path, deck, fencing), all mandatory inspections, and the occupation certificate. There are no hidden extras.

For many Illawarra property owners, yes — particularly those who are negatively geared or cashflow stressed. Adding a granny flat can generate $15,000–$33,000+ per year in additional gross rental income from an asset you already own, without requiring a new purchase, new mortgage, or new stamp duty. As with all investments, outcomes depend on your specific circumstances — we’d recommend discussing with your accountant or financial adviser.

Yes. Each dwelling has its own tenancy agreement, rent, and tenant. They operate completely independently from a tenancy perspective. The properties share a single lot (you cannot subdivide them), but the rental arrangements are entirely separate.

The first step is a free site inspection. Call us on (02) 4203 3554 or submit an enquiry online and we’ll be in touch to arrange a time that suits you.