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Granny Flat Builders – The Ultimate List

When planning your granny flat, you may be looking for help from a professional granny flat builder. Of course, you only want the best to help you with your development. So, I have prepared a list of the highest reviewed granny flat builders in Australia.


To help find one near you, below you will find a list of granny flat builders in each State of Australia.


I will also discuss what makes a great granny flat builder,


DON'T PAY A FORTUNE FOR YOUR GRANNY FLAT. Find out how to deal with council and build a granny flat for the lowest cost possible. Learn More.

  • What questions you need to ask your builder
  • How to break down costs and what pitfalls to avoid


List of Granny Flat Builders in NSW:



If you are looking for a more detailed list in Sydney – See this post of Sydney Granny Flat Builders as well.

If you want a little more insight for granny flat builders in Newcastle, see this post. And if you want specific advice for Granny flat builders on the Central Coast, please see this list here.


Listed below are the highest reviewed granny flat builders in Queensland. In no particular order.


 List of Granny Flat Builders in QLD:



I have listed below the highest ranked granny flat builders in South Australia – in no particular order.


List of Granny Flat Builders in SA:



Listed below, in no specific order are the highest reviewed granny flat builders in Western Australia.


List of Granny Flat Builders in WA:



See below for a list, in no particular order of the highest ranked granny flat builders in Victoria.


List of Granny Flat Builders in VIC:



Below are the highest reviewed granny flat builders in the ACT. They are listed in no specific order.


List of Granny Flat Builders in the ACT:



What Makes a Great Granny Flat Builder


Choosing a builder for your granny flat is one of the most important decisions you will make. You will want to put time, research, and careful thought into the decision. Basically, not all granny flat builders are the same.


Successful builds are about great communication and getting along with the builder you choose


If you’ve already started looking, you may have seen a big difference in the:


  • Designs
  • Building types, and
  • Services offered between builders.


So, here are some important things to consider, and critical things to do, when looking for your granny flat builder.


  • Check they are a licensed builder – Unfortunately, not everyone who advertises is a registered builder. Check this yourself by visiting http://www.licensedtrades.com.au/ and entering their license number.
  • Check their memberships – Are they associated with the Master Builders’ Association, HIA, or any other professional industry body?
  • Are they aware of all regulations specific to your area – Each Council has their own rules, make sure they know yours. Familiarise yourself with the rules for your area, then see if they know them by asking a few questions. If they do not know the answers, they are probably not experienced granny flat builders. Even better is a builder that will assist you with all your paperwork (i.e. your approval), helping to relieve your stress. A great granny flat builder will help you with permits and other legal documents, ensuring you have an enjoyable experience.
  • Good communication – You’re putting your hard-earned money into something and trusting them on your property. Friendly communication is the key to establishing an accommodating relationship with your builder. Good communication means they will get the job done to a professional standard. This includes keeping you updated as to the progress of your project.
  • Promptness – Delays occur, but if a builder promises you a deadline, they should do their best to stick to it. This includes sending quotes swiftly or responding to queries quickly.
  • Experience – Not much surprises an experienced builder, as they’ve seen it already. They can conquer difficulties, within budget.
  • Expert knowledge – Every builder is a specialist in their own field – some in renovations and extensions, others in new builds. Make sure the builder you choose is the expert in the type of granny flat you are developing. A good way to tell is, if the builder can’t help you choose a design, then leave. Fast.
  • Fairly priced – Get quotes from several builders to ensure you’re getting a fair price.


If you can find a builder with the above qualities, you’ve found yourself a great granny flat builder – book them in advance!


Questions to Ask a Granny Flat Builder


So, not only is it important to choose a good builder, it’s also important to develop a good relationship with them from the start. How, you ask? Well, to help you – below is a list of essential questions you should ask;


  • What is your license number? As mentioned, it’s critical to check if they are a licensed builder.
  • Can I have some references and a list of completed projects? Even ask if it’s possible if you can walk through a granny flat that they built. By doing so, you can check the quality of their build.
  • Can you show me some of your recently finished projects? The difference between this and the question above is that:
  • You’re asking for addresses of properties that are currently under construction. You can learn a lot from visiting these – what you want to see is clean, well-organised worksites.
  • How many projects are you currently working on? The number of projects a builder is able to take on will give you some insight into;
  • The size of the company, and
  • Potentially, their ability.

A smaller company isn’t a bad thing – they may give you their full attention. However, a larger business is likely to have more experience, which also helps to keep costs low.

So it will also pay to ask:

  • “How many granny flats do you build a year?”, and
  • “Can you give me a guaranteed construction timeframe?”.
  • How far from where I’m building do you work? This makes a significant impact.

If your property is outside of your builders’ normal area, they may not send out their normal team of tradies. Instead, they may hire unused sub-contractors, which may lead to a low-quality build.

  • At what time/s of construction can I inspect the build? It’s important that your builder involve you throughout the process. If not, you could discover mistakes at the final walk-through. It’s best if your builder gives you direct access to your building supervisor, who will update you with calls, emails and photos.
  • Do I Have a Building Maintenance Period? Following handover of your property is your opportunity to;
  • Discuss concerns regarding the construction and have them repaired by your builder. 12 months is a pretty standard time.
  • Who Is My Building Supervisor? Research your supervisor’s experience, including length of employment. This is the key person overseeing your build, ensuring it is high-quality. Preferably, you should have an open line of communication with your site supervisor, and they should visit regularly.
  • How Long Has Your Company Been Operating? Working with a builder with little experience is not advised. Ask your builder a bit about their history, such as how long they have been operating in your area. Ask them how many awards they have won, to reinforce their integrity. Another thing that is ill-advised is signing up to a builder with poor financial history – you’re risking them leaving you mid-build. It’s probably best you leave them before they leave you. Start looking elsewhere.
  • Do You Have Builders Indemnity Insurance? You insure your dog in case it swallows something it shouldn’t. So, make sure your builder has a Certificate of Currency to cover you in case something unforeseeable occurs.


You now know if you have found yourself a great granny flat building company, a great building team.


Best Way to Break Down Costs with a Builder


By now you should know to request quotes from at least 3 builders. When comparing the quotes, compare “apples against apples” – that is, check the inclusions.


What you’ll notice is that some builders will only quote the bare necessities, while leaving out essential items. These are known as “hidden costs” in a quote and are often left out to make their quote look cheap in comparison to other builders.


So, potentially, if you thoroughly assess the cheapest price and obtain prices for the “hidden costs”, you may find that the final price can be:


  • Higher than other companies that included all costs in their quote.


So, if you find a builder that has satisfied your list of questions, it’s time to break down your granny flat costs. It’s best to find a builder that has an open, trustworthy, fully transparent work ethic. This can be ascertained through their quote.


After all, you want to feel fully informed and in control in what is a big financial investment. So, you want an all-inclusive, detailed Builders’ Quote, based around the costs specific to your requests and land.


As far as being aware of “hidden costs” in your quote, this is how they may (or may not) appear:


  • Approval and Certification fees – A good builder will apply these fees to your quote, either as a fixed fee or allowance.

If they appear as an allowance, it’s important to make sure that your builder has calculated their guess from correct information.

That is, they have the experience and skill to assess your property, your plans and the relevant Council fees and rules specific to your site.


  • Site Preparation Costs – If your builder has not inspected your site before drafting your quote, you can be fairly sure it isn’t accurate.

Why? It will exclude key costs relating to your site, as a thorough inspection has not been undertaken.

So, your builder has not provided accurate site preparation costs i.e. land clearing, demolition, site excavation.

Instead, your quote will be based on them having easy access to site, and this is not always the case.

Even if your builder doesn’t conduct these services, they should be able to out-source to a reliable company.


  • Temporary Site Requirements – Things such as temporary fencing and a site toilet should all be familiar to your builder.

So, they should know how much to allow for these.


  • Internal & External Fit-Outs – This is a particularly well-known area for “hidden costs”.

Ensure you thoroughly read your quote and confirm with your builder they have allowed for all fit outs.

This includes flyscreens, taps, door handles, etc.

They may sound small, but they can have a big impact on your budget if not included.


  • Energy Efficiency Requirements – When the plans for your granny flat are drawn, it’s energy efficiency will be considered.

These specifications (i.e. insulation rating or use of glazed windows) should be acknowledged in your quote.

This ensures the costing is accurate and guarantees your builder will use the recommended materials.


While some costs are unexpected, your builder should also have a Policy on Unforeseen Building Costs that you can read. This Policy should describe what steps will be taken if an issue occurs (i.e. hitting tree roots or sewer mains on site).


While you may not encounter any of these issues during your build, it’s a good idea to have an idea of how they can affect you. Finally, once you have decided on a builder, to protect yourself against “hidden costs”, ask them for an exclusions list.


This list will show anything that is not included in your quote.


It is important you know that the price of inclusions you choose (i.e. your fittings and fixtures) may just be an estimate, as


  • The exact make, model and amount may not be known until construction.


So, make it clear that you should be advised of any changes to the building schedule that are made, including:


  • If certain materials must be substituted, the builder must change them for those that stay within your budget.


If you haven’t advised them of this, they may use fixtures and fittings that cost more than you budgeted for. The final and important question to ask your builder is – “When is it my final chance to make any changes?”.


What you do not want is to get hit with additional, unnecessary charges, just because you change your mind midway through building. So, find out your builders’ cut-off date for alterations, and make sure that you are happy with your design before it’s too late.


Now you have a good, honest, open line of communication between you and your builder, keep those lines open. Ensure your builder knows your priorities. Then, ask their advice on finding ways to save on things such as design.


As experts in their field, a great builder will know how to assist you.


Paying a Builder as an owner-builder


If you plan on project managing the granny flat build and simply want to hire a builder as opposed to a “building company” there are 3 common way to pay them:


  1. Pay by the Hour
  2. By the Job Carried Out
  3. By the Week


Pay By the Hour


This is a common way to arrange payment with a builder, especially if you plan on doing some of the labour yourself.


It is also a great way to arrange payment if you know your builder won’t be on site every day due to other jobs they are working on.


Pay for the Job Being Done


Lets say you want to do some labour yourself and you don’t care that they take their time doing a job.


For instance, if you want to hire a builder to put up the frame for you, you can agree of a price to pay them for this one job. And if they take a week to do that, between other jobs there is no stress that budgets are being blown out of the water.


As long as you have both managed expectations on how long a job will take.


Pay By The Week


You might need a builder to be there for you to do the work and to give you advice on parts you are not sure of.


Paying an agreed salary for “X” number of weeks could suit this type of scenario. As long as both parties are happy with the figure.


And you have agreed that certain jobs will be completed in a fixed time frame stated in a contract.


Pitfalls to Look Out for When Hiring a Builder


When you’re looking for a great builder for your granny flat, be prepared to wait. Research has shown that you should start planning in advance – builders need months’ notice.


Anything less than this, and alarm bells should ring.


Other mistakes to avoid include:


  • Hiring the wrong builder – Know the area of expertise of your builder and hire one specifically to suit your project. For example, do not hire a builder that is good at renovation to construct a new, detached granny flat.
  • Not Getting the Proper Feedback – When you ask a builder for their references, they are only going to give you their best. So, ask for more. Then, contact those clients and ask them the following questions:


  • Were they nice to work with?
  • Did they communicate well?
  • Were they fair and trustworthy?
  • Was the project completed on schedule?
  • Was it completed within budget? Or were there additional costs?
  • How were problems handled?
  • How was their quality of work?
  • How was the follow-up process?


This should let you know their level of skill. Request to visit granny flats similar in size and style to yours. If possible, try to visit one recently completed, one under construction, and one completed 5- 10 years prior.


Then, ask yourself these questions:


  • Does their work have warranty and termite protection?
  • Were problems corrected?
  • How does the unfinished construction site look?
  • Did the oldest project suitably last the length of time?


  • Not Verifying their License – Make sure your builder has a licence to build. Ask to see their licence and certificate of insurance. A builder with a licence will protect you. For example, worker’s compensation is usually a contractors’ responsibility, not yours. However, not if the contractor doesn’t have a licence or insurance – then it is your problem.
  • Not Getting a Detailed Quote – Only choose a builder that offers a thorough quote. A well-detailed quote shows the builder understands your priorities. I suggest you start by making a shortlist of potential builders that you want to hire. Talk to them, and request quotes. Thoroughly examine the quotes and contemplate your choice. Remember, the cheapest quote isn’t always the best.
  • Signing the Contract before You’re Ready – Don’t commit to anything before you have all the information. Such as, until your permits have been approved, and all costs have been finalised.




Building a granny flat is a significant investment, so it pays to do your research. A high-quality builder is the key to a stress-free build.


A checklist to ensure they are a great builder is:


  • Check their license, rewards, and memberships.
  • Check their reputation by asking for references. Contact those references to get feedback.
  • Ask to visit previous granny flats they have built – one recently completed, one under construction and one finished 5-10 years ago. This way you can check their quality of construction and finishes.
  • Response times i.e. answering queries or sending quotes – good communication is essential. Ideally, you will also have direct contact with the supervisor, who will keep you updated with the progress on site.
  • Guarantees and warranties i.e. what are your warranties after handover, and what are your rights if you’re not happy with something.
  • If they will they commit to a construction timeline.


When you have found a builder that meets your requirements, it’s time to crunch the numbers – the contract is important. It should be clear and all-inclusive, so you know exactly what you’re paying for.


Ask for an exclusions list and prepare for the extras. Be aware that there are unknowns in the construction process and familiarise yourself with these.


But, with good planning, design and management and an open line of communication with your builder, costs can be minimised. So, with a bit of time and research, and you can find the perfect granny flat builder.


Spending a few extra dollars at the beginning could save you thousands all up.