The Process Of Building a Granny Flat (& Everything You Need To Know)

If you’re planning on building a granny flat, you’ll need to prep up.

Demand for these crafty dwellings has peaked in the last decade, and the reason is obvious. Harsh interest rates and steep mortgages have sparked a need for smarter living and viable investing.

But like anything profitable, building a granny flat has turned mainstream, which means the potential challenges can stack up. You’re going into a market dominated by hungry investors and greedy developers, so the competition is fierce.

Whether you’re living smart or smartly investing, here’s everything you need to know before, during, and after the build. Doing the extra work and careful planning can go a long way to a smooth project, so keep this guide handy the whole way through.

The most important thing to remember is to be patient. It’s common to have an arsenal of questions when excitement for your new granny flat ignites, so make sure you’ve got a reliable builder (don’t go too far).

Happy planning!

1. Planning & Deposit

Your first step is to find the right design. That’s going to depend on what exactly you want to accomplish, as well as suitability for your block and budget. Unless you’re an expert, it’s a good idea to talk to your builder about this.

If your builder can’t help you choose a design, then run away fast. There are better options available.

Once things get moving, it’s time for your paperwork and approval process. It’s boring, but it needs to be done.

When we get the go-ahead, we’ll schedule the build into small, periodic intervals. That way we can complete everything on-time and on-budget without leaving you in the dark. We’ll also order the materials needed for construction and secure all relevant services and trades ahead of time.

What you need to know: Getting your plans approved and finalized will take at least 20 days, so start early. At this stage, we also recommend you read all the information packs provided as they contain important information about your project and any relevant regulations. To get started, head over to the NSW Planning Portal.   


Planning on borrowing? Make sure your credit score is in order before you apply for finance. 

2. Site Clear & Preparation

This is when the fun starts (for us). We prepare the site for building by clearing any debris or obstacles in your backyard (say goodbye to that old clothesline and garden gnome set, unless you intend to keep them). We’ll also need to make sure there’s space to fit any required material or tools so they don’t disrupt your primary residence.

backyard clearance for granny flat build

What you need to know: If there are any existing structures in your backyard (such as a garden shed or cubby house), they’ll need to be demolished. It’s best to do this yourself or through a third-party as demolition is not included in our pricing, but we can do it at an extra cost.

As per council regulations, we’ll also need to inform your neighbours that you plan on building a granny flat. It’s a good idea if you discuss this with them as well to make the process as smooth as possible (and let them know what an awesome job were doing).

If there are cars that are usually kept on your street, they may need to be moved on some days to clear access for tradesmen or heavy machinery.

3. Piers & Slab Foundation

When the areas clear, our surveyors mark the terrestrial boundaries and touch-points of where your granny flat will be built. At this stage we’ll also carry out any required excavation.

Then we pour the supportive slab and erect the piers. These are the framework of the entire building, showing you exactly where your granny flat will stand. You’ll also start to see its overall shape and layout. A termite barrier is also incorporated at ground level.

concrete slab for new granny flat build

What you need to know: Now that you have an exact view of where your granny flat will be on your block, you can start deciding where to put other backyard ornaments like your clothesline, storage shed, or garden. At this stage you’ll know exactly how much room you have available, so you can keep everything nicely spaced without interfering with the build.

4. Frame Erection

Next, we erect the key structure of your granny flat. We use industry-standard timber frames (or you can upgrade to steel if you’re feeling lavish) to set out the internal and external bearings. In laymen terms, this is the skeleton of your granny flat.

Here you’ll start to notice the separation of different areas like the bedrooms and bathroom, as well as the height of the building.

timber frames of new granny flat

What you need to know: Now that you know where each bedroom and window will be, you can factor in how much sunlight you’ll get in different parts of your dwelling. This is important to consider when making interior design decisions as the natural flow of light plays a key role in the look and feel of your granny flat.

Take note of where the sun shines over the erected structure. If there are areas which are low on sunlight, then start planning where you’ll be able to place mirrors to draw in more light, or potentially remove protruding branches or shrubs that may be blocking light from coming in.

5. Lock-Up

As the name suggests, the lock-up phase involves enclosing the granny flat from top to bottom. The vertical roof and guttering is installed using our peerless blend of colours and styles. Then we lay the external brickwork to fully seal the building.

This is where you’ll finally start to notice the cunning outdoor appearance of your new sanctum (if you’ve chosen a good builder).

Exterior brickwork during granny flat construction

What you need to know: Once the exterior starts to show its lively vigour, you’ll get to see exactly what you’ll be coming home to everyday.  Now you can start planning other aesthetic features around your granny flat to complement its colour scheme.

If you plan on putting in a garden, consider how the floral pigments will match the style of your roof and façade cladding.

6. Linings & Utilities

As the structure is now fully enclosed, we can start working on the interior of your granny flat. We’ll start installing main utilities such as plumbing and electrical systems. We also reinforce the internal walling with insulation and plasterboard mounting.

water tank with boiler at new granny flat

What you need to know: If you plan on renting out your granny flat, you’ll need to make sure it has a separate electricity meter. That way you can track exactly how much your tenants use and avoid potential disputes over splitting bills.


Check out our tips on reducing your granny flat’s energy bill. 

7. Kitchen Structure

No granny flat is complete without an esteemed cookery (or in simple terms, that place you where make the nachos and dip). This step is dedicated to installing your kitchen cabinets and other storage units, as well as fitting in key appliances like your cook-top. It’s usually easier to start with your kitchen before any other interior work.

new kitchen during granny flat construction

What you need to know: Wait until the kitchen is finalized before stocking up on any additional appliances you want (such as a fridge, coffee machine, or blender). You’ll need to make sure they fit nicely and don’t clutter your limited cooking space.

If you’re short on space, you can install wall-mounted shelves or upgrade to a kidney pull-out for extra storage. Here’s some space-saving hacks every granny flat owner needs to know. 

8. Flooring & Fix-Out

To match the outdoor seduction of your granny flat, we fit-out and stylize the rest of the interior. This is when your granny flat shows signs of a true home, with the final tiling, flooring, shower screens, paint-work, and other accessories also fitted.

If your design includes optional add-ons such as extra carpet, air-conditioning, or blinds, they’ll also be added now.

bathroom of granny flat build

What you need to know: Be careful when moving in large, heavy appliances such as your fridge and beds. These can scratch your new flooring, so we recommend using protective plastic and big burly men to do the lifting. When adding your lamps, shelves, or curtains, consider how they will look against the rest of the interior too.

9. Practical Completion & Handover

Now you’ve got a fully built, decked-out granny flat. But it’s still not official. We do one final inspection, checking that everything’s up to our picky standards of safety and workmanship. We’ll also test all appliances and electrical functions to make sure they’re in safe, working order.

After a thorough cleanup and official handover, your new granny flat is finally built and ready for action.

completed granny flat build in Sydney

What you need to know: Renting is a tough gig, so make sure you’re ready to be a landlord.

Start by listing your granny flat on popular accommodation services. Here’s where you’ll get the most traction:

Before accepting any tenants, remember to do a background check and take a security deposit. This is the best way to ensure you get cooperative and responsible renters. Here’s everything you need to know about finding tenants and maximizing your returns. 


Still lost? Talk to us for a free site inspection, or with any questions you have. We’re here to help.