Pros and Cons of Granny Flats in Perth

More and more Perth homeowners are looking at granny flats as a smart way to add value to their properties, create extra living space, or even generate rental income.

But is a granny flat the right choice for you?

Before making any decisions, it’s essential to weigh the benefits and drawbacks. While granny flats offer affordability and flexibility, they also come with certain limitations, such as council regulations and upfront costs.

In this article, we’ll break down the key aspects of building and owning a portable building so you can make an informed decision.

For Investors: If you want rental income and increased property value, this is a smart, low-maintenance investment.
For Families: If you need an affordable housing solution for parents or children, this solution provides independence while keeping loved ones close.

Why Are Granny Flats Gaining Popularity in Perth?

Also known as secondary dwellings, they are self-contained living spaces built on the same property as a primary residence.

These compact homes typically include a bedroom, bathroom, kitchen, and living area, making them fully functional for independent living. They can be attached to the main house or built as a separate structure in the backyard.

Whether it’s to accommodate aging parents, provide a private space for adult children, or generate rental income, these versatile dwellings offer numerous benefits.

Key Features:

Self-contained living space with essential amenities
Flexible usage – can be used for family members, guests, or tenants
Legal and council-approved under Western Australia’s zoning regulations
Various sizes and designs to suit different property layouts
Potential for additional income through rental opportunities

Granny Flat Benefits

✔ Boosts Property Value and Market Appeal

In Perth’s competitive real estate market, homes with additional dwellings are often seen as more desirable. This portable building can add up to 30% more value to your property, depending on factors such as size, quality, and location.

With rental demand on the rise, buyers see them as an attractive feature, offering extra space for family members or tenants.

This makes your property stand out in the market, potentially leading to a higher resale price if you decide to sell in the future.

✔ Provides a Steady Rental Income

They offer an excellent opportunity for homeowners to generate passive income.

With Perth’s rental market experiencing low vacancy rates and increasing demand for affordable housing, a well-located granny flat can bring in $300 to $500 per week in rental income, depending on its size and location.

✔ Affordable Housing Solution for Families

They provide an economical alternative for aging parents, adult children, or extended family members who need their own space but want to stay close to loved ones.

Building a portable building is often cheaper than purchasing a separate home.

The average cost in Perth ranges from $120,000 to $200,000, significantly lower than the median house price, which currently exceeds $600,000.

✔ Versatile Use for Different Life Stages

It isn’t just for renting or housing family members—it’s a multi-purpose space that can adapt to different needs over time. Some homeowners use it as:

A home office or studio
A guest house for visiting relatives
A short-term Airbnb rental for extra income
A retreat for teenagers seeking independence

This versatility ensures that your investment remains useful even if your needs change. Whether you’re working from home today or need extra space for guests in the future, this portable building offers long-term flexibility.

✔ Relatively Fast Construction Time

Most constructions in Perth can be completed in 12 to 16 weeks, depending on the complexity of the design and council approvals.

This shorter timeline means homeowners can start benefiting from their portable buildings sooner, whether through rental income, extra space, or increased property value.

Many companies offer prefabricated or modular options, further reducing construction time and minimising disruption to your main residence.

✔ Energy-Efficient and Cost-Effective Living

Modern solutions are designed with energy efficiency in mind, making them cost-effective to run. Many builders incorporate sustainable features such as:

Solar panels
Rainwater harvesting systems
High-quality insulation
Energy-efficient appliances

Since these portable buildings are smaller than full-sized homes, they require less energy for heating, cooling, and maintenance, leading to lower utility bills.

Potential Drawbacks

Council Regulations and Zoning Restrictions

Although Western Australia has relaxed some laws to encourage secondary dwellings, homeowners must still comply with zoning requirements, property size restrictions, and building approvals.

Some common regulatory challenges include:

Minimum lot size requirements – Generally, your property must be at least 450m² to qualify for a granny flat.
Limited dwelling size – In Perth, they cannot exceed 70m² of internal living space.
Council approval process – Depending on your local council, securing permits and approvals can be time-consuming and may take several months.
Utility connections – Additional plumbing and electrical work may be required, which could increase overall costs.

NEW: Granny Flat Council Requirements: Everything You Need to Know (and Plan For)

Significant Upfront Costs

The cost of building a standard one-bedroom in Perth ranges from $120,000 to $200,000, depending on factors such as design, materials, and additional features.

Other potential expenses include:

Development application fees
Architectural and engineering plans
Connection to existing utilities (water, electricity, sewerage)
Landscaping and fencing adjustments

Limited Privacy for Homeowners and Tenants

If the secondary dwelling is located too close to the main house, it may result in noise disturbances, shared outdoor spaces, and reduced personal space for both parties.

Common privacy concerns include:

Shared driveways and entryways
The limited separation between living areas
Noise transfer from daily activities

To address these concerns, many homeowners opt for strategic landscaping, fencing, or soundproofing solutions, but these modifications can add extra costs.

Ongoing Maintenance and Management

Just like any other property, they require regular maintenance and upkeep. Whether you’re using it as a rental property or housing family members, you’ll need to budget for repairs, cleaning, and general upkeep over time.

For rentals, additional responsibilities may include:

Tenant management – Finding and screening tenants, handling lease agreements, and ensuring timely rent collection.
Property wear and tear – Increased use of utilities, plumbing, and appliances can lead to more frequent repairs.
Compliance with rental regulations – Ensuring your portable building meets Western Australia’s tenancy laws and safety standards.

Potential Impact on Outdoor Space and Aesthetics

Portable building inevitably reduces the amount of available outdoor space on your property. This could be a drawback if you enjoy a large backyard for recreation, gardening, or entertainment.

Some common concerns regarding space limitations include:

Less room for landscaping or gardens
Reduced backyard space for children or pets
Potential impact on the property’s aesthetic appeal

Not All Properties Are Suitable for Granny Flats

Not every Perth property is physically or legally suitable. Some challenges that may prevent construction include:

Sloping or irregularly shaped blocks that make construction difficult.
Existing structures (such as pools, sheds, or trees) that may need to be removed.
Strata or heritage-listed properties may have restrictions on secondary dwellings.

Pros	Cons
Boosts property value – Can increase resale value by up to 30%.	Council regulations – Strict zoning and approval processes.
Generates rental income – Potential to earn $300–$500 per week.	High upfront costs – Construction can cost between $120,000–$200,000.
Affordable housing solution – Cheaper than buying a separate home.	Privacy concerns – Close proximity may reduce personal space.
Versatile usage – Can serve as a rental, guest house, or office.	Ongoing maintenance – Requires regular upkeep and repairs.
Quick construction – Typically completed within 12–16 weeks.	Reduces outdoor space – Less room for gardens and recreation.
Energy-efficient – Lower utility costs due to smaller size.	Not all properties qualify – Sloping or strata lots may be unsuitable.

Granny Flats vs. DIY and Alternative Housing: Which is the Better Option?

Granny Flats vs. DIY Home Extensions

DIY Home Extensions: Customised but Costly

Some homeowners choose to extend their existing home instead of building a separate portable building. This could mean adding extra rooms, converting a garage, or building a second storey.

Pros:

Fully integrates with the existing house.
Increases overall living space without requiring a separate dwelling.
More customisation options.

Cons:

Expensive – Full home extensions can cost between $150,000 to $400,000, often exceeding the cost of a portable building.
Longer construction time – Extensions can take 6–12 months to complete.
Disruptive – Ongoing construction affects daily life in the main house.

Verdict: If you need additional space within your main house and have a larger budget, an extension may be worth considering. However, if you prefer a self-contained, quicker, and more affordable solution, a granny flat is the better option.

Granny Flats vs. Tiny Homes

Tiny Homes: Portable but Restricted

Tiny homes are small, transportable dwellings designed for compact living. They are often mounted on trailers, making them semi-mobile, and are a popular choice for minimalists.

Pros

Lower cost – Can range from $50,000 to $150,000, depending on size and features.
Portability – Can be relocated if necessary.
Eco-friendly – Designed for minimal energy use.

Cons:

Legality issues – Many councils in Perth do not allow tiny homes as permanent residences.
Smaller space – Usually under 40m², significantly less than the 70m² allowed for granny flats.
Limited resale value – Tiny homes do not add value to your property.

Verdict: Tiny homes are ideal for those seeking affordable, mobile living. However, if you want a legal, long-term housing investment, granny flats are the superior option.

Granny Flats vs. Modular Homes

Modular Homes: Quick Build but Requires More Land

Modular homes are prefabricated houses built in sections and transported to the site for assembly. They are typically larger and designed as primary residences.

Pros:

Faster construction – Can be completed in 6–10 weeks due to off-site fabrication.
Customisable designs – Offers a range of layouts and styles.
Energy-efficient – Built with sustainable materials and better insulation.

Cons:

Higher cost – Prices start at $200,000+, making them more expensive.
Requires more land – Often unsuitable for small suburban properties.
Council approvals – May face stricter zoning and building restrictions.

Verdict: If you have a large block of land and a bigger budget, a modular home could be an attractive alternative. However, for Perth, homeowners looking to maximise existing space, granny flats remain the more practical choice.

Granny Flats vs. Shipping Container Homes

Shipping Container Homes: Innovative but Limited

Repurposed shipping containers are gaining popularity as an affordable and unique housing solution. These homes are constructed using steel containers and can be stacked or modified for different layouts.

Pros:

Low cost – Prices start from $50,000, making them cheaper than most alternatives.
Quick setup – Basic designs can be completed in a few weeks.
Sustainable – Reuses materials, reducing environmental impact.

Cons:

Council restrictions – Many Perth councils do not approve shipping container homes as permanent dwellings.
Insulation challenges – Requires significant modifications to be comfortable in Perth’s climate.
Resale value concerns – Not widely accepted in the property market.

Verdict: Shipping container homes are great for budget-conscious and eco-friendly homeowners, but they lack the long-term investment appeal and legal certainty of granny flats.

Granny Flats vs. Other Housing Options: A Quick Comparison

Feature	Granny Flats	DIY Home Extensions	Tiny Homes	Modular Homes	Shipping Container Homes
Cost	$120,000–$200,000	$150,000–$400,000	$50,000–$150,000	$200,000+	$50,000+
Size	Up to 70m²	Custom size	Under 40m²	Varies (larger than granny flats)	Varies (usually small)
Construction Time	12–16 weeks	6–12 months	4–8 weeks	6–10 weeks	2–8 weeks
Zoning/Approval	Permitted on residential lots	Requires council approval	Often not approved for permanent living	Subject to zoning laws	Often restricted by councils
Resale Value	Increases property value	Increases property value	Does not add value	Increases property value	Limited resale value
Best For	Rental income, family housing, long-term investment	Larger homes with custom needs	Affordable, minimalist living	Quick-build homes for large properties	Budget-friendly, eco-conscious owners

Start Your Journey with Perth’s Trusted Experts

Choosing the right solution is a big decision, and having the right experts by your side makes all the difference.

At Portable Buildings WA, we specialise in high-quality, council-approved granny flats designed to suit Perth’s unique housing needs.

With years of industry experience and a commitment to excellence, we ensure your project is handled with precision, compliance, and cost-effectiveness—so you can avoid expensive mistakes and delays.

Ready to explore your options? Whether you’re looking for extra space, rental income, or a long-term investment, we’re here to help.

Contact Portable Buildings WA today at (08) 9393 4855 or claim your fast and FREE quote online to save time and money.

Pros and Cons of Granny Flats in Perth – What You Need to Know