A secondary dwelling—commonly called a granny flat—is a self-contained dwelling established in conjunction with a principal dwelling on the same lot. It may be within, attached to or separate from the principal dwelling. The formal classification depends on the approved use and documents, not a marketing label or construction method. This guide therefore uses the NSW planning term secondary dwelling.
Conjola Park is identified here through Australian Bureau of Statistics locality record SAL 11012. SAL means the ABS Suburbs and Localities geography. SAL boundaries are statistical approximations and are not cadastral, title, zoning or council boundaries. The supplied record covers approximately 2.8985 square kilometres and overlaps the ABS statistical LGA named Shoalhaven. That statistical LGA name must be distinguished from the formal organisation name, Shoalhaven City Council, and the overlap does not establish which council administers a legal parcel.
State planning rules provide the framework, but an address-specific investigation must establish the responsible council, zoning, planning instruments, title conditions, existing approvals, services and relevant constraints. The NSW Planning Portal Spatial Viewer is a useful starting point, not a substitute for title records, a survey, formal approval documents or professional property advice.
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Local granny-flat overview
The locality-specific evidence is limited but useful for context. The 2021 Census Conjola Park QuickStats recorded 298 people, 186 private dwellings and a median age of 51 within the SAL. These are historical figures from the 2021 Census edition, not current population, housing or market measures. They do not show present rental demand, property values, household needs, lot characteristics or development capacity, so using them to support a commercial forecast would be unsafe.
The Census values describe people and dwellings counted within a statistical boundary at that time. They do not identify which dwellings were principal dwellings, secondary dwellings or otherwise suitable for alteration. They also cannot establish whether a particular property has the area, lawful structures, servicing or planning characteristics required for a proposal. Locality statistics should therefore inform community context only, while feasibility remains a parcel-based exercise.
The supplied ABS geography records all of the Conjola Park SAL area within the statistical Shoalhaven LGA. For a parcel confirmed as being administered by Shoalhaven City Council, the council’s Local Environmental Plan information identifies the route to the Shoalhaven Local Environmental Plan 2014 and its maps. The council also provides official online mapping tools. Their applicability must be checked against the legal lot; the SAL overlap alone is not authority to apply those controls.
Under the NSW secondary-dwelling guidance, a secondary dwelling operates in conjunction with a principal dwelling and stays on the same lot. This development type does not create a separately subdividable, titled or independently saleable residence. A freestanding building is not automatically a secondary dwelling, and a garage, shed or studio cannot be treated as habitable merely because it has enough physical space.
The same guidance states that secondary dwellings are permitted in residential zones R1, R2, R3, R4 and R5 and may be permitted in other zones where the applicable local environmental plan provides for them. Permissibility is only an initial legal question. The zone, planning pathway, site standards, title, lawful principal dwelling and proposal must all be verified. For rural or other non-residential land, review the applicable local environmental plan rather than transferring residential-zone assumptions.
There is no verified locality-wide evidence here about lot sizes, zoning, services, access, topography or property constraints. Those features can differ between addresses. Local feasibility should begin with the street address, lot and deposited plan, title, approval history and current official mapping.
Council rules and approval pathway
A secondary dwelling may be assessed through a development application or, where every applicable requirement is met, as complying development. A development application is assessed by the responsible council under the relevant planning instruments and considerations. NSW guidance states that development applications are lodged online through the NSW Planning Portal.
Complying development is a standards-based pathway. A council or appropriately registered certifier may issue a complying development certificate only after confirming that the proposal satisfies the statutory criteria, mapped exclusions and applicable development standards. The Department’s complying-development guidance explains the certifier’s role and the need to comply with certificate conditions.
For the Housing SEPP complying-development pathway, NSW planning guidance identifies a lot area of at least 450 square metres, except where the secondary dwelling is located entirely within an existing dwelling house. This is one bounded eligibility requirement, not a universal minimum for a council-assessed application and not sufficient by itself to establish the complying pathway.
Test a proposed complying development certificate against the current State Environmental Planning Policy (Housing) 2021, including its Schedule 1, and the applicable provisions of the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008. Current in-force legislation should be used rather than superseded Affordable Rental Housing SEPP material or an undated checklist.
Before choosing either pathway, confirm the legal parcel and administering council. If Shoalhaven City Council is confirmed, check the current local environmental plan, maps, development control plan, application requirements, contributions, fees, stormwater and waste requirements, and any driveway or vehicle-crossing process. Planning instruments and administrative requirements can change, so the material applying on the application date matters.
Property investigation should also cover the title and deposited plan, easements, covenants, restrictions, boundaries, legal access, sewer and drainage assets, utility locations and existing approvals. Planning consent does not necessarily remove private title restrictions. Use current official records to identify any relevant mapped or property-specific matters, such as heritage, bushfire, flooding, biodiversity, coastal hazards, acid sulfate soils or contamination, without assuming that any one of them affects Conjola Park generally.
The Housing SEPP does not itself require additional parking for a secondary dwelling. Existing consent conditions, removal of existing parking, safe access, manoeuvring and applicable local controls may still require assessment.
Following approval, the project may require construction certification, appointment of a principal certifier, prescribed inspections and evidence that approval conditions have been met. Service NSW explains that an occupation certificate is required before occupying or using a new building, or using an existing building after an approved change of use. A concept plan, quotation, BASIX certificate or builder statement is not an approval.
Costs and budgeting
A useful budget starts with an investigated site and a documented scope. Advertised package prices cannot account for differences in access, ground conditions, demolition, retaining, service capacity, drainage, approval requirements, conversion work or finishes.
Prepare separate allowances for:
- title, planning, survey and service investigations;
- design, engineering and specialist reports;
- application, Planning Portal and certifier charges;
- council contributions and authority charges where applicable;
- demolition, excavation, earthworks, retaining and site access;
- the building contract, fixtures and finishes;
- stormwater, sewer, water, electricity and communications;
- paths, driveways, fencing, landscaping and waste removal;
- BASIX documentation, inspections, certificates and handover; and
- insurance, finance expenses and unresolved project risks.
Obtain itemised, like-for-like quotations based on the same drawings, specifications and site information. Require each tenderer to identify exclusions, provisional sums, site assumptions, service allowances, approval responsibilities, BASIX items and external works. Confirm current fees directly with the relevant council, certifier, Planning Portal and utility authorities rather than carrying forward an earlier quotation.
Maintain a budget register that links every quoted item to the drawings, specification and responsible party. Update it when investigations reveal additional work or when the approved design changes. Before accepting a variation, record its scope, price effect, documentation effect and relationship to certification. This process helps distinguish a genuine scope change from work that should already have been included in the contract.
The current Building Commission NSW contract guidance requires a written contract for residential building work costing more than $5,000, with more extensive large-job requirements above $20,000 and a maximum deposit of 10%. Read the Consumer Building Guide and align progress payments with completed contractual stages. Home building compensation cover applies where required for work valued at $20,000 or more, including GST. Verify the certificate, contracting entity and site through the official HBC Check before making a payment or allowing work to start.
For a proposed conversion, budget for investigation of the existing structure’s lawful status and condition. Structural adequacy, fire safety, waterproofing, insulation, ventilation and services may require work that is not visible during an initial inspection.
Design and site considerations
Define whether the secondary dwelling will be within, attached to or separate from the principal dwelling. That decision affects classification, construction interfaces, documentation, privacy and the appropriate BASIX secondary-dwelling project type. Obtain approval records before relying on an existing structure as part of the proposal.
Use an accurate survey to record boundaries, levels, buildings, easements, access and significant site features. Test the layout for daylight, ventilation, visual and acoustic privacy, private open space, waste storage, clothes drying, maintenance access and safe movement between the street and both dwellings. Review any effect on existing parking and vehicle access under the rule described above.
Check floor area, setbacks, height, landscaped area, site coverage and earthworks against the exact approval pathway and current instruments. A standard copied from another council, another development type or an earlier version of legislation may be inapplicable. Confirm the applicable controls with the responsible council or certifier before finalising the footprint.
Resolve stormwater and wastewater arrangements during feasibility. Identify lawful discharge points, sewer or other wastewater requirements, utility capacity and authority approvals. Locate infrastructure before excavation and ensure that the proposed works respect easements and third-party rights.
Coordinate the site plan with the internal design rather than treating them as separate tasks. Door locations, windows, plant, bins, clothes drying and utility equipment can affect circulation and privacy outside the building. Allow practical access for maintenance and emergency response, and ensure that construction access can be achieved without relying on unverified rights over neighbouring land.
The NSW BASIX guidance explains the water, energy-use and thermal-performance framework for applicable residential development. Integrate BASIX commitments into orientation, glazing, shading, insulation, ventilation, fixtures and services. Carry the approved commitments consistently through the drawings, specifications, contract and completed work.
Address constraints only after official evidence shows they are relevant to the parcel. Where a mapped or property-specific issue applies, obtain the reports and design advice required for that issue. Prefabricated, modular or relocatable construction remains subject to the planning, building, BASIX and certification requirements applying to its use and site.
Rental and investment considerations
Before offering the premises for occupation, confirm that the secondary dwelling was lawfully approved, constructed consistently with its approval and issued the required occupation certificate. Its same-lot status also matters when considering lending, insurance, valuation, management and any future sale of the property.
If the approved premises are rented under a residential tenancy, follow NSW Fair Trading’s current guidance on residential tenancy agreements and the Residential Tenancies Act 2010. Use the current prescribed agreement and processes, and verify requirements for bonds, condition reports, disclosure, repairs, safety and notices.
Family occupation, boarding, licensing, short-term accommodation and a standard residential tenancy are not necessarily equivalent arrangements. Check the legal and planning requirements for the intended use rather than applying tenancy guidance indiscriminately.
For practical management, decide how occupants will use entrances, paths, parking, outdoor areas, waste facilities and clothes-drying spaces. Record responsibility for gardens, shared infrastructure, maintenance and utility charges. Check the legal requirements before installing separate metering or passing utility costs to an occupant.
Assess rental feasibility using recent evidence from suitably qualified local professionals. Verify that any comparable premises have similar approval status, condition, access and inclusions, and distinguish advertised asking prices from achieved rents. Obtain property-specific lending, insurance, taxation and financial advice before committing to a rental strategy.
Keep the rental assessment separate from the construction budget. Document operating responsibilities, likely maintenance demands and insurance conditions using property-specific advice. This produces a more useful decision record than applying generic suburb-level assumptions to a dwelling whose approval, condition and occupancy arrangement may differ from advertised examples.
Choosing a granny-flat builder
Identify the legal entity that would sign the contract, then use the official Service NSW facility to check the builder or tradesperson licence. Match the entity name and licence number to the proposed contract, and confirm that the licence is current and its category covers the work. An ABN, industry membership or review score is not a licence check.
Ask for recent references from comparable secondary-dwelling projects. Where possible, speak with clients and inspect completed work with permission. Ask about communication, site-cost changes, variations, defects, documentation and after-completion service.
Give each tenderer the same drawings, specifications and requested scope. Compare:
- inclusions, exclusions, allowances and provisional sums;
- excavation, retaining, access and ground-condition assumptions;
- stormwater, utility and service-connection responsibilities;
- planning, certification and inspection responsibilities;
- BASIX commitments and nominated products;
- external works, landscaping and waste removal;
- variation and extension-of-time procedures;
- defects, statutory warranty information and handover documents.
Clarify whether the quotation is based on approved construction documents or an early concept. Record who will coordinate consultants, answer council or certifier requests, arrange inspections and provide certificates for occupation.
Use the appropriate written contract and read the Consumer Building Guide supplied under the current official contract guidance. Check the applicable cooling-off information, progress-payment stages, variation process, defects procedure and statutory warranties before signing. Obtain independent advice on unclear terms.
Ask how the builder records inspections, product substitutions, concealed work and departures from the approved documents. Require the handover scope to identify certificates, warranties, operating information, keys and defect records. Verify statutory warranty information against the current official guidance and retain the signed contract, approved plans, variations, payment records and completion documents together.
Where home building compensation cover is required, verify the certificate through HBC Check as described in the budgeting section. Ensure that the insured builder, property and work match the contract. Compare total documented scope and risk allocation rather than selecting a tender solely by its headline price.
Planning and feasibility checklist
- Confirm the address, lot and deposited plan.
- Verify the legal title and lawful principal dwelling.
- Confirm the administering council from parcel records.
- Check current zoning and planning instruments.
- Review official parcel mapping and relevant overlays.
- Obtain title, survey, service and approval records.
- Define the proposal as internal, attached or separate.
- Test both available approval pathways.
- Confirm applicable design and BASIX requirements.
- Resolve drainage, sewer, access and utility needs.
- Verify application documents, fees and contributions.
- Compare itemised quotations on one scope.
- Check licences, contracts, warranties and required cover.
- Obtain approval before construction starts.
- Complete required inspections and certification.
- Obtain the occupation certificate before occupation.
- Use current tenancy documents if renting.