Investment Property Development in the Southwest: A Designer's Perspective on What Makes a Good Project
Cutting design quality to protect development margins is a false economy. It costs more in approval delays, construction inefficiencies, and diminished resale value than the design saving ever delivers. The projects that perform best over time are the ones that are designed to be good, not just compliant.
The Southwest has attracted significant investment interest, driven by population growth, the sea-change migration trend, and a property market that has consistently outperformed expectations in recent years. For investors looking at residential development, understanding what makes a project viable from a design and planning perspective is as important as the financial modelling.
Why design quality matters for investment returns
• Approval efficiency — councils across the Southwest are applying increasing scrutiny to design quality in multi-residential DAs. Poorly designed projects attract requests for additional information, referrals for further review, and sometimes refusals. The carrying cost of a 6-month approval delay on a development site is real and significant.
• Construction cost efficiency — a well-resolved design minimises construction waste. Simple structural grids, straightforward roof forms, and efficient planning reduce labour and material cost compared to complex plans with irregular angles and multiple roof changes.
• Rental and resale — dwellings with adequate natural light, functional room proportions, and usable outdoor areas achieve better rental yields and higher resale values. The premium for quality design over minimum-compliance design is often recovered within a single tenancy cycle.
What makes a good investment unit design
• Efficient floor plans — every square metre costs money to build. An efficient two-bedroom unit of 70m² can feel more spacious than a poorly planned unit of 90m² because of how the space is organised. Good design maximises room area by minimising corridor.
• Natural light to living areas — the single most complained-about feature of poorly designed units is inadequate light. It affects how the dwelling feels to live in and how easily it photographs for marketing. Solving this requires deliberate orientation and window placement.
• Parking that doesn't dominate — R-Code parking requirements must be met, but a site plan dominated by driveways and concrete is visually unappealing and reduces landscaping area. Clever site planning integrates parking efficiently.
• Private outdoor spaces with quality — the R-Codes set minimum outdoor living areas. Meeting the minimum isn't always the right answer, a slightly larger, better-positioned outdoor area improves liveability significantly and can be the deciding factor for a prospective tenant or buyer.
Realistic development timeline for the Southwest
From initial feasibility to occupancy, a realistically managed small unit development in the Southwest should be planned at 24–36 months. The breakdown typically looks like:
• Feasibility and design — 2–3 months.
• Development application processing — 3–6 months, depending on council and site complexity.
• Building permit — 6–10 weeks after DA approval, assuming documentation is complete.
• Construction — 8–14 months for a small, grouped housing project, depending on scale and contractor availability.
Carrying costs during this period, interest, rates, and holding costs, need to be modelled from the start, not discovered partway through the project.
Frequently Asked Questions
What is the minimum lot size for a duplex in Bunbury?
In the City of Bunbury, the minimum lot size per dwelling at R20 density is 350m² (average 450m²). A 700m² lot at R20 can therefore theoretically support two dwellings. The practical buildable area, after setbacks, parking, and outdoor living requirements, determines whether a compliant design is actually achievable. A feasibility assessment will tell you.
Is survey strata or green title better for a unit development?
This can be variable to the lot and the specific investor outcome requirements, we recommend discussing this with a Planning Consultant.
What is the realistic return on a Southwest unit development?
Returns vary significantly by location, product type, and market conditions. We can help you with the design and planning feasibility; for financial modelling we'd recommend working with a local property analyst or real estate professional who understands the Southwest market.
Assessing a development site in the Southwest? Let's run a proper feasibility, design and planning inputs that make your financial model realistic, not optimistic: projects@fastlanedesign.com.au
