Doraemon EPS Bun House: Unlocking the Granny Flat Market with Thermal Insulation Innovation

In Sydney’s Northern Beaches, a 60-square-meter granny flat was completed within a week. The owner, James, was amazed to find that even during the hottest summer days, the indoor temperature remained at a comfortable 23-25°C, while his air conditioning bills were nearly half that of his neighbors’ similarly sized properties.

This granny flat, built using Henan Yajiate Green Building Technology Co., Ltd.’s Doraemon EPS Bun House technology, represents a new force in Australia’s residential market.

As Australia redefines its national housing targets and the society ages, green building solutions that offer thermal insulation, rapid construction, and cost-effectiveness are facing unprecedented market opportunities.

Market Opportunity: Soaring Demand for Granny Flats

Recent data from Domain reveals a significant trend: in 2024, “granny flat” has topped the search keywords list for property seekers in Sydney, replacing the long-standing favorite “pool”.

This shift reflects a pragmatic choice under housing affordability pressures—the backyard is no longer just for leisure, but a potential source of rental income.

CoreLogic Research Director Tim Lawless notes that “nationwide, there could be more than one million residential properties ideal for granny flats or secondary affordable dwellings”.

Data shows approximately 242,000 properties in Sydney are suitable for granny flat development, with nearly 230,000 potential sites in Melbourne and 185,000 in Brisbane.

The economic benefits are substantial: In areas like Sydney’s North Shore and Northern Beaches, a well-built granny flat can command weekly rents of AUD $800-$1,000, offering owners a gross return of up to 18-20%.

Product Innovation: Three Key Features of Doraemon EPS Bun House

Henan Yajiate Green Building Technology Co., Ltd. targets this market opportunity with its Doraemon EPS Bun House solution, meeting core market needs with unique performance advantages.

Thermal Insulation: Combating Australia’s Extreme Climate

The Doraemon EPS Bun House uses flame-retardant molded expandable polystyrene foam board (EPS) as its core material, containing 3-6 million independent closed cells per cubic meter and an air content exceeding 98%.

This structure provides exceptional thermal insulation properties, with a heat transfer coefficient as low as 1.0W/m².K.

This characteristic is particularly valuable during Australian summer extremes—it effectively blocks heat transfer, maintaining a cool interior and significantly reducing air conditioning energy consumption.

The material also meets technical standards for artificial climate aging resistance, withstanding 250 hours without cracking, making it durable against Australia’s intense UV exposure.

Construction Speed: Main Structure Completed Within a Week

The seemingly impossible task of “two people building a house in less than a week” becomes a reality with EPS modular construction technology.

The Doraemon EPS Bun House features an interlocking design similar to Lego bricks. All components are precision-prefabricated in the factory, requiring only simple assembly on-site. The lightweight components (each block weighs approximately 9kg) are easy to stack, test, adjust, and significantly reduce construction difficulty and time costs.

Compared to the traditional 4-5 month construction cycle for granny flats, the EPS Bun House technology can reduce the construction period to approximately one-quarter of the traditional time, allowing owners to generate rental income or address housing needs much faster.

Cost-Effectiveness: An Economical Green Choice

The cost advantages of the Doraemon EPS Bun House are multi-dimensional:

• Controlled Direct Construction Costs: Factory production ensures consistent quality, reducing on-site adjustments and waste.

• Reduced Energy Consumption Costs: Excellent thermal performance dramatically lowers heating and cooling costs in winter and summer.

• Minimal Maintenance Costs: The material offers strong weather resistance, with surface impact resistance (standard type ≥3J, reinforced type ≥10J) and is less prone to damage.

This cost structure contrasts sharply with traditional granny flats, whose construction costs have risen from AUD $100,000-$160,000 in 2011 to a typical AUD $200,000-$250,000 in 2025.

Technical Core: Exceptional Performance of EPS Material

The core technology of the Doraemon EPS Bun House lies in its use of Flame-Retardant Expandable Polystyrene Foam Board (EPS).

This material system comprises EPS boards, special bonding mortar, fiberglass mesh, and a finish layer.

The EPS material itself possesses excellent physical properties: density ≥20kg/m³, tensile strength ≥0.2 N/mm², compressive strength ≥0.15 N/mm².

Particially, its heat resistance (75°C) without deformation and cold resistance (-80°C) without brittleness make it suitable for various climates across Australia, from north to south.

The material’s low volume water absorption rate of only 0.5%, oxygen index of 30%, and self-extinguishing property within 2 seconds provide both waterproof performance and fire safety.

Application Scenarios: Beyond Traditional Granny Flats

The Doraemon EPS Bun House holds diverse and extensive potential in the granny flat market:

Multi-Generational Living Solution

With adult children staying home longer and grandparents needing nearby care, the EPS Bun House provides families with a “together but separate” living solution that balances privacy and convenience.

Sustainable Income Asset

For highly leveraged homeowners, adding an EPS Bun House in the backyard for rental can generate stable cash flow at weekly rents of AUD $550-$1,000, effectively hedging against interest rate risks.

New Option for Retirement Living

Retirement Living Council (RLC) Executive Director Daniel Gannon points out that “almost 80% of retirement villages already provide varying levels of care to residents”.

The Doraemon EPS Bun House can serve as a complementary form for retirement communities, offering a new living option for seniors who prefer independence but require some level of care.

Installation Process: Simple Four-Step Activation

The installation process for the Doraemon EPS Bun House is significantly simplified:

1. Site Preparation: Level the ground and prepare a simple foundation.

2. Module Assembly: Interlock and assemble the prefabricated EPS modules according to numbering, as easily as building with Lego bricks.

3. Securing and Reinforcement: Fix the structure using nylon and steel nail expansion bolts.

4. Surface Treatment: Apply polymer surface mortar, complete mesh bonding, and finish with the decorative layer.

The entire process requires only a small crew and generates almost no construction dust or noise.

Policy Alignment: Consistent with Australian Housing Directions

Multiple features of the Doraemon EPS Bun House strongly align with the current direction of Australian housing policy:

The RLC is advocating for aged care beds to be included in the Prime Minister’s national housing targets—the EPS Bun House is a feasible pathway to help achieve this goal.

NSW’s 2009 AHSEPP policy stipulates that lots ≥450㎡ with building areas ≤60㎡ can bypass council approval and be directly approved—the scale of the Doraemon EPS Bun House fits this standard perfectly.

State governments are opening fast-track approval channels for aged care and residential projects: in South Australia, since September, retirement village projects valued over AUD $10 million that include co-located aged care can be treated as essential infrastructure.

Market Outlook: The Right Time for Green Building

Australia is moving towards the goal of achieving a 75% prefabrication rate for new buildings by 2025, and the prefabricated construction method of the Doraemon EPS Bun House fully aligns with this trend.

Furthermore, as the integration of retirement communities and aged care facilities becomes a trend—with nearly 80% of retirement villages already providing varying care levels—the EPS Bun House, potentially integrating basic age-friendly features, has broad application space.

The HIA predicts that the number of new granny flats nationwide in 2026 will be ten times that of 2022—indicating tremendous potential for market growth.

In a backyard on the Central Coast, a Doraemon EPS Bun House was completed just two days ago, and a tenant has already moved in. The homeowner, Mary, said, “It’s even better than I expected. Not only is the rental return stable, but the energy efficiency has made the tenant very satisfied.”

Similar scenes are quietly unfolding in cities across Australia.

Henan Yajiate Green Building Technology Co., Ltd.’s Doraemon EPS Bun House is using technology and innovation to provide the Australian granny flat market with a green building solution that is more energy-efficient, faster to build, and more economical.