Granny flat costs

When it comes to the costs involved in granny flat construction, there are a variety of factors to consider when deciding on a budget – including design, building costs, cost of materials, and potentially even council fees. Which is why it’s important to work with a licensed granny flat builder who can provide transparency on the overall cost at every stage of the granny flat build, including any additional costs that may arise.

We cover all things cost in this comprehensive guide to granny flat costs, plans and prices, including a breakdown of expenses and how to get the most bang for your buck – not to mention the value a backyard build can add to your property and the potential extra income you could make from a granny flat rental.


A breakdown of granny flat plans and prices

From fixed-price granny flats to custom upgrades, costs vary depending on the builder, the type of granny flat, and the features you choose to include. In other words, to ensure you spend your dollars wisely and avoid hidden costs, you’ll need to consider more than a single price tag.

Let’s crunch some numbers!

How much will it cost to build a granny flat?

From $80,000 to $330,000.

When it comes to estimating granny flat prices, there’s no short answer. There are a variety of factors that will influence the cost of building your granny flat. These factors are not always apparent to new buyers at the start of the process (especially if you’re dealing with the wrong builders), so we’ve outlined the key cost considerations you need to know about.

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Custom built granny flats vs granny flat kit homes

On the surface, a granny flat kit home for $80,000 appears to be a “wallet-friendly” solution over a custom-built granny flat. However, many kit home companies fail to provide the full turnkey price as supplied by custom granny flat builders, which means you can end up facing a variety of hidden or unexpected costs, including:

  • Site costs;
  • Service connection;
  • Electrical and plumbing essentials;
  • Council or Complying Development Approvals;
  • Inclusions such as blinds, floor finishes, letter boxes, and everything you’d need to move in.

With a custom granny flat quote from the right builder, you can be sure all key features are covered in the overall cost. But it’s not all about granny flat prices – from flexible designs to guaranteed timeframes, there are plenty of reasons why you should opt for a custom granny flat over a kit home. Thank us later!

Choosing the right granny flat builder

Once you’ve made the call to invest in a granny flat of your own, the next step is to decide on a builder who can make it happen. Make sure you choose a reputable granny flat company to take care of the granny flat build with:

  • Appropriate Building Licenses;
  • References and Google Reviews; and
  • An informative website to prove it!

Be conscious that not all granny flat companies deliver the same standards. Some act merely as project managers. Some are designers or architects that may not have a building background or have the knowledge to assess what is practical on your block. Look for experienced specialist builders, as this will make a huge difference to your overall experience and end product.

At Backyard Grannys, we’ve changed the lives of over 1,500+ customers and our transparent process and turnkey solutions mean you know everything (and we mean everything) that’s included in your quote from the start. To top it off, we cover a wide range of features and services at no extra cost.

Start off on the right foot with some more tips for choosing your granny flat builder.


Granny flat plans and prices

We’ve collated plans, quotes, final figures and data from over 9 companies from Sydney all the way to Newcastle and here are the cost inclusions for all granny flats plans and prices:

  • Site costs: Specific reports and consultation costs imposed by your site.
  • Design & approval: Architectural planning design and navigating the approval process with local council/CDC.
  • Build price:  Cost to build your chosen design.
  • Inclusions: Chosen finishes and features.

And of course, you need to factor in the size of your granny flat!


How much should YOU spend?

Designing your granny flat should be a completely personal process. While many are simply looking for an affordable housing solution, others are looking to build the small home of their dreams. There really is no limit to what can be achieved, with custom designs fast becoming the norm for new owners. If your budget allows, the design possibilities are endless.

Find out how much it will cost for your granny flat idea. Get in touch for a free quote and site inspection.


Other granny flat price considerations

Choosing the foundation: Concrete slab vs bearers and joists

One of the first financial decisions to make is to choose the foundation material: a concrete slab or bearers and joists.

At Backyard Grannys, we include a concrete slab in the standard build cost for each granny flat. As well as formwork, waffle pods and steel reinforcement, and this process will involve pump hire. If you’re working with a flat site, a concrete slab is hands down the most affordable foundation for your granny flat.

It’s another story if you need to excavate and level the site or in a flood effected zone – that’s when bearers and joist floor systems come in. We offer this option to anyone building a granny flat foundation on a sloping block – a process that requires additional costs for scaffolding. That said, when you’re dealing with a steep slope, bearers and joists are more cost-effective than a concrete slab because they eliminate the need for excavation and retaining walls.

Still not sure? Check out our blog to further compare the value of concrete slabs versus bearers and joists.

The safe and cost-effective solution to caring for elderly relatives

We all want our loved ones to grow old somewhere they feel safe, supported and happy. But you don’t have to fork out eye-watering monthly charges to cover the cost of running their retirement village. You also don’t need to have grandma and grandpa move into your main house, which could harm their sense of independence and comfort (and leave you with even less privacy and personal space).

Let’s talk numbers for a minute. Many nursing homes are paid for with an upfront Refundable Accommodation Deposit, which can cost anywhere from $250,000 to $550,000 (or a daily charge of up to $50 a day). At that rate, 20 years of aged care means paying the nursing home a total of $365,000 – a sum which could have been used to build a granny flat that will live on as a valuable asset for future generations.

In short, a granny flat allows you to keep your money in the family instead of giving it to a retirement home – all whilst creating the perfect home for your loved one. By building a granny flat on your property, your relatives can enjoy privacy and independence, while at the same time receiving whatever familial support and custom accessibility they need.

Find out more about the benefits of granny flat living for elderly relatives.

A positively geared investment for your portfolio

If we haven’t caught your interest yet, maybe the fact that a granny flat could earn you upwards of $14k per year will. And there’s big bonuses for the landlord too.

Purchasing or building a granny flat is usually more cost-effective than buying a standalone investment property. That means you can get your investment portfolio off the ground without taking out a large loan – not to mention the significant depreciation entitlements a granny flat will bring.

All in all, renting your granny flat is an excellent way to monetise that extra space you already own, but don’t use. With an average ROI of 10-20%, you’ll enjoy a nice boost in annual income.

Here are some pointers to maximise your granny flat returns:

  • Do your homework to make sure it’s a viable investment: Consider council regulations, the demand for rental properties in your neighbourhood, and the cost of installing a granny flat before making your final decision.
  • Source reliable quotes from builders: This will help you to form a clear picture of exactly how much the build will cost.
  • Adding a granny flat to an investment property: If building on an existing investment property, weigh up the cost of maintaining both dwellings and the overall rental impact of adding a granny flat to this site.
  • Be consistent: To add value to your property, make sure your granny flat compliments the aesthetic of your existing home without taking up too much yard space.

To learn more about how building a granny flat can be a positive asset, you can get some investment inspiration from this Central Coast granny flat success story to discover just how much you could earn from a granny flat rental each year! Alternatively, learn more with our ultimate guide to granny flats in Australia.

Key takeaways

  • Cost factors: The cost to build a granny flat varies significantly based on design, construction, materials, and council fees.
  • Price range: Costs range from $20,000 to $290,000, depending on size and customisation.
  • Custom vs. Kit Homes: Custom-built flats offer transparency and fewer hidden costs compared to kit homes.
  • Choosing a builder: Select reputable builders with appropriate licenses and positive reviews.
  • Investment benefits: Granny flats can provide additional living space, care solutions for elderly relatives, and positive financial returns through rentals.
  • Cost breakdown: Includes site costs, design and approval, build price, and standard inclusions.

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