Build Boost Benefit - Granny Flat Masterclass

Our Granny Flat Seminar brought together experts in planning, sales, finance, construction, and tax to show how ancillary dwellings can boost income and property value. Speakers shared insights on council requirements, design, rental management, tax considerations, financing options, and building processes, highlighting practical tips, common pitfalls, and strategies for success. The session demonstrated that with expert guidance and careful planning, granny flats offer a smart, long-term investment opportunity with dual income, stronger cash flow, and enhanced property value. Below is the video of the seminar.

Peter Ng –  PAR Property Developments Consultants

Peter broke down the planning requirements for granny flats (ancillary dwellings) across Perth, including the Cities of Belmont, Canning, Armadale, and Kalamunda.

He explained that while state rules (R-Codes 2024) set the base allowing up to 70m² internal area, no minimum lot size, and rental flexibility each council applies its own policies.

Common pitfalls include zoning issues, parking/access challenges, and exceeding 70m², which triggers a Development Approval.

Peter emphasised that correct design and advice can save time, money, and stress, and his team assists with feasibility checks, applications, and council variations to ensure a smooth approval process.

Nick Souris – Sunset Constructions

Nick outlined the step-by-step process of building a granny flat, from feasibility and approvals to construction and handover. He highlighted that compliant builds typically go straight to CDC and Building Permit, while non-compliant or heritage sites require a Development Approval (DA).

He explained key build sequence stages slab, frame, lock-up, fit-out, and handover and shared insights on cost drivers like siteworks, construction type, finishes, and services. Nick also compared contract types, with cost-plus offering flexibility and fixed price providing certainty.

Nick stressed the importance of planning and design considerations, including setbacks, privacy, utilities, and durable finishes, which can improve rental yield and long-term value. He also shared practical safeguards to keep projects on track: early surveyor engagement, parallel DA & BP submission, insurance alignment, and prompt council responses.

Finally, he addressed common questions: DAs are only needed for non-compliance, approvals can range from 10 days (CDC) to 60–90 days (DA), and utilities/parking must be planned early to avoid delays.

Raveen Liyanage – Sales Director, Porter Matthews Metro

Raveen presented a real-life buy-and-hold granny flat project, showcasing how a well-planned dual-income strategy can boost returns and long-term property value.

A 1967-built 4x2 home on an 813m² block, purchased for $555,000, currently rents for $700 per week (6.5% yield). With the addition of a new 3x2 granny flat, the total rental income is projected at $1,350 per week, lifting the yield to around 8% and future value to $1M+.

The design focuses on privacy and subdivision-style separation, enhancing tenant appeal and overall marketability.

While approvals and site issues (like asbestos removal) caused some delays and extra costs, Raveen highlighted the importance of planning for contingencies and taking a long-term investment view.

Melanie Quadros – Business Development Manager, Porter Matthews Metro

Melanie shared real examples of granny flats leased by Porter Matthews Metro, highlighting strong rental demand and returns across Perth suburbs such as Maddington, Beckenham, Thornlie, Gosnells, Langford, and Midland.

Recent leases ranged from $350–$620 per week, with newer builds achieving the highest returns and older conversions performing well when well-maintained. Properties with good separation between dwellings consistently attracted stronger tenant interest and rental outcomes.

Melanie also outlined key legislation around utilities, noting that landlords can only charge tenants for water, gas, or electricity if the property is individually metered or if a fixed charge is clearly stated in the lease. She compared two practical solutions fixed usage agreements versus sub-meter installation with sub-metering offering better long-term accuracy and fewer disputes.

She closed by reinforcing the Porter Matthews Metro Advantage — a full-service team guiding investors “from concept to cashflow” with proven results, trusted partners, and tailored strategies that deliver peace of mind, stronger returns, and smarter investments.

Adi Desai – Ardent Advisory

Adi outlined the key tax considerations when building and renting out a granny flat, covering deductions, capital gains, and compliance.

He explained that owners may be able to claim interest on loans, rates, utilities, and depreciation (Div 40 & 43), depending on how the property is used.

However, renting out a granny flat can impact the main residence CGT exemption, and each case must pass the interest deductibility and use tests. Adi advised seeking professional tax guidance to ensure compliance and avoid ATO issues.

Gayan Mudalige – Commercial & Personal Finance WA

Gayan provided practical guidance on how to finance a granny flat project, outlining the main options available personal loans, home equity loans, mortgage refinancing, and construction loans. Each comes with different interest rates, eligibility criteria, and risks to consider.

He explained that lenders require a Tentative On Completion (TOC) valuation, and most loans are capped at an 80% Loan-to-Value Ratio (LVR). Before approval, owners must provide council approvals, builder quotes, and insurance details, with progress payments made throughout construction.

Gayan also noted that while a granny flat can enhance rental yield and flexibility, it may not always increase overall property value particularly for modular or detached builds.

He emphasised the benefits of working with a mortgage broker, who can assess financial position, prepare documentation, negotiate better loan terms, and streamline the approval process for a smoother, more strategic finance journey.

** The information provided in this blog is for general informational purposes only and does not constitute professional advice. While we strive to ensure accuracy, we encourage readers to conduct their own research and due diligence before making any decisions based on the content or sources mentioned. Porter Matthews Metro does not assume any liability for errors, omissions, or reliance on the information provided. **