Multigenerational Home Design — Building for Extended Families in Western Sydney
Western Sydney has one of Australia's highest rates of multigenerational living. Across Fairfield, Liverpool, Canterbury-Bankstown, and Cumberland, families with three generations living under one roof — or on one property — are common. Cultural tradition, economic practicality, and family connection all drive this choice.
But designing a multigenerational home requires more than adding extra bedrooms. It requires careful planning of privacy, accessibility, independent living areas, and separate access — while maintaining a cohesive family home. Buildana (Lic. 487805C) designs custom multigenerational homes across Western Sydney. Here is how to get it right.
Layout Options for Multigenerational Living
There are four primary layout approaches, each suited to different family structures:
1. Dual master suite: A single home with two master bedroom suites, each with ensuite and walk-in robe, at opposite ends of the house. The family shares kitchen, living, and outdoor areas. Best for: parents and adult children, or parents and grandparents who are comfortable sharing daily living spaces.
2. Attached secondary suite: A self-contained wing attached to the main home with its own bedroom, bathroom, kitchenette, and separate entry — but connected internally via a shared hallway or door. Best for: elderly parents who want independence but need proximity for care. This layout qualifies as a single dwelling under planning rules (not a granny flat).
3. Main home plus granny flat: A main dwelling plus a separate 60 sqm granny flat on the same block. Completely independent living with separate entry, kitchen, bathroom, and outdoor area. Best for: families wanting full privacy between generations.
4. Duplex with family: Two full-size dwellings on one block — one for each generation. Each dwelling is independent with separate title (Torrens) possible for future flexibility. Best for: large families with two independent households who want to be neighbours.
Buildana has built all four configurations. The right choice depends on your family's dynamics, your block, and your budget.
Design Principles That Make Multigenerational Homes Work
Privacy separation: This is the single most important design element. Families who share kitchens and bathrooms experience friction. Families with separate living zones and separate bathrooms — even if they share a kitchen — report higher satisfaction.
Design strategies for privacy: • Stagger bedrooms so they do not face each other across a hallway • Provide a second living area (rumpus, retreat, or sitting room) so generations can watch different programs • Separate bathroom per generation — ideally per bedroom or per couple • Sound insulation between the secondary suite and main living areas (R2.5 acoustic batts in shared walls) • Separate external entry for the secondary suite or granny flat
Accessibility: Grandparents may have reduced mobility now or in the future. Design their suite on the ground floor with: • Level or ramped entry (NCC 2025 requires step-free entry anyway) • Wide doorways (820mm clear — NCC 2025 requirement) • Hobless shower (NCC 2025-compliant bathroom) • Non-slip flooring throughout • Grab rails in bathroom (or reinforced walls for future installation) • Good lighting — natural and artificial
These features cost almost nothing when designed in from the start. Retrofitting them later is expensive and disruptive.
Cost Guide for Multigenerational Homes
Based on Rawlinson 2026-adjusted rates for Western Sydney:
• Dual master suite home (250–300 sqm, medium-high brick veneer): $615,000–$795,000 — Compared to a standard 4-bed home (220 sqm): add $50,000–$80,000 for the additional suite, bathroom, and separation
• Attached secondary suite (280–350 sqm including suite, medium brick veneer): $690,000–$930,000 — The secondary suite (40–60 sqm) adds approximately $120,000–$160,000 including kitchenette, bathroom, separate entry, and sound insulation
• Main home + granny flat: Home (220 sqm) $540,000–$585,000 + Granny flat (60 sqm) $130,000–$165,000 = $670,000–$750,000 — The granny flat requires separate CDC approval and separate service connections
• Duplex: Two complete dwellings (2 × 150–200 sqm) = $650,000–$980,000 — Includes demolition of existing dwelling, construction of both, external works
The attached secondary suite is often the most cost-effective option — it provides independent living within a single dwelling under one roof, avoiding the need for separate approvals and separate service connections.
Planning Rules and Approval Pathways
Multigenerational homes have different planning implications depending on the layout:
• Dual master suite: Classified as a single dwelling. Standard CDC or DA approval. No additional planning complexity.
• Attached secondary suite: If it has a separate kitchen (even a kitchenette), some councils may classify it as a 'secondary dwelling' — which has specific rules under the Affordable Rental Housing SEPP. Ensure the design is assessed correctly.
• Granny flat: Requires a separate CDC application under the State Environmental Planning Policy (Affordable Rental Housing). Maximum 60 sqm internal area. Must be on a residential-zoned lot of at least 450 sqm.
• Duplex: Requires dual occupancy approval (CDC or DA) and the block must meet minimum lot size and frontage requirements.
Buildana navigates the planning rules for every multigenerational design. We ensure the approval pathway is clear before you invest in detailed design. For granny flat options, see /homes/granny-flats. For duplex designs, see /duplex/duplex-developments. For custom home design, visit /homes/custom-homes. Contact us at /contact to discuss your family's needs.
