Granny flat designs Sydney, don’t think for a minute that just because it’s a small build on your own property, that you don’t have to follow some rules.  Actually, there are a number of different rules, some which will require legal advice, some which require you to follow state laws and some that you just might need someone else to handle.

In NSW, the state laws that govern the building of granny flats come straight from the NSW Government’s Affordable Housing State Environment Planning Policy. Here are the main policies governing granny flat design:

  1. The minimum residential lot size you need to build a granny flat is 450m2 (with a 12m2 frontage)
  2. The maximum external dwelling size is 60m2

Your granny flat designs must have:

  • 3m setback from the rear
  • 0.9m setback from any side boundaries
  • 3m setback from any trees over 6m high

If your property and projected build size or granny flat designs don’t fit these requirements, it doesn’t mean that you definitely can’t do it; it just means that you need to submit a Development Application to your local council.

These applications can be tricky and are best prepared by a specialist. Premier Granny Flats can organise this process for you.

house plans with granny flats attached

In the meantime, you can contact your local council to see if there are any further provisions for your particular shire. Or, let us take the stress and worry out of the process and handle it all for you.
It might pay to get some legal advice if the issue of ownership is going to be part of your build.

If your granny flat build is a housing solution for parents or other extended families, which someone other than the main property owner is paying for, you’ll need to make sure that your arrangements are documented somewhere. At the very least, this measure is taken to preserve family relationships.

Worst case scenario, if litigation ensues, there is a clear picture of who owns what and everything can be settled with a minimum of fuss. Families do need to stick together and help each other out but just for your own peace of mind, make sure you take some legal advice before committing to this type of arrangement.

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Contemporary granny flat designs to suit every purpose

Granny Flat Design Solutions

Depending on your property type, what you want to use your granny flat for and the location of your property, there are three options available to you; you can convert, extend or construct.

1. Construct

This is by far the most cost effective way to add a granny flat to your property, if you have the appropriate spaces to do so. Any renovations under your existing roof line are always going to be cheaper than extending the roof or building a whole other dwelling.

The most common area to convert is an under-roof garage. There are still a few requirements that need  be considered before making this a reality such as raising the level of the floor but on the whole, if you have a space such as this, you could easily, quickly and cost-effectively create a granny flat with a clever design.

2. Extend

This refers to a granny flat that is attached to your house. Usually, there would be an access door from the house to the granny flat, which can be locked for privacy. Quick access to ageing parents in distress is a big bonus with this one.

Often, home owners have an unused room and adjoining bathroom or laundry that can be converted, and they simply add on some living spaces with an extension.

While you can potentially add much more than just a single living space, you may be limited by local laws, space or your budget. Check with your builder, which of the  granny flat designs, would work best to extend your home and be the most cost-effective. 

3. Construct

If  we’re talking cost, this is the most expensive option.  Why? Because usually you’re starting from scratch. Unless you have some kind of detached shed or garage that already has plumbing and electrical, you are essentially doing a new build, just on a smaller scale. All connections to services will need to be done, just like a regular build. The advantage to this option is the privacy it affords residents in the main house and the value it adds to your property. 

Particularly if you are planning on renting the granny flat to non-family members, your privacy could potentially be compromised if your renters are living under the same roof line. A separate dwelling means more options in terms of the kinds of rental arrangements you can manage.
Similarly, if your granny flat is not under your roof line then it isn’t taking any spaces away from the main dwelling. Your 4 bed, 2 bath home doesn’t become a 3 bed, 1 bath with a granny flat, which could potentially impact the value of the property as well as making it a squishy arrangement in the main dwelling.

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Working out which option is right for you is really about identifying why you are building the granny flat in the first place. Each of these options can be designed in a smart, contemporary way that uses the space efficiently and effectively; you just need to decide on granny flat designs that suit your particular purpose.

granny flats sydney prices

Granny Flat Flat Packs – too good to be true?

There’s no easy answer for this one. Granny flats in flat-pack form can be seen advertised from as little as $10,000. The old adage rings true here though, 

‘If it seems to good to be true, it probably is’.

Digging a little deeper, you’ll find that the $10,000 flat packed granny flat is, in fact, just the shell of the granny flat, nothing more. Further, the cost of constructing the shell often runs higher than the price of the materials. 

So, what can you really expect to pay for a completely finished, high-quality granny flat?

Custom granny flat designs Sydney, that is, getting an original design, made for exactly the purpose you intended, will start at around the $110,000 – $150,000 mark for a turn-key build.

Adding bedrooms, bathrooms and custom fittings will add to that figure, as will the complexity of the building site. 

Comparing a Granny Flat Designs Sydney flat to a flat pack granny flat, there is a chance that the flat-pack could save you a few dollars. But before you take the plunge, consider what you are getting for your hard-earned cash and whether this will do the job that you want it to. A poorly designed or presented granny flat will detract from your home and could potentially decrease the overall value. 

You want this investment to add value to your property, not detract from it, so doing it right and engaging a licensed, high-quality builder to build to a well-thought-out, original granny flat design that will suit your purposes and complement your home, is well worth the cost and could end up saving you money in the long run.

Granny Flat Designs Sydney Testimonial


I’ve built many houses in my time but this is the first time I’ve built a granny flat. Premier Granny Flat Designs Sydney are hands-down one of the best in the business. Their project management puts some of the larger builders to shame. They know so much about the building game, let alone granny flats, that all you have to do is take their advice, pick one of their granny flat designs and everything will run smoothly. I am recommending you to all my friends. Thanks guys! “.Granny Flat Build 5 Star Rating

Paul C, Sydney

We know our Granny Flat designs are perfect for the Sydney Climate!

Common Granny Flat Designs Questions

What is a granny flat?

A granny flat is a second dwelling on an existing property that sits behind the main dwelling or as an extension to the main dwelling. Traditionally, it was used to provide housing for elderly family members.

These days, Granny Flat Designs Sydney has a variety of uses including, art studios, teenage retreats, music/teaching studios or rooms, and more and more commonly, as rental properties to provide an extra income stream.

Can you build your own granny flat Designs?

The short answer is ‘yes’ but you need to jump through a few hoops before you can do that. You’ll need to check your state regulations but most will insist that you start by obtaining an owner/builder licence. This is a bit more than an application in most cases.

You’ll probably need to do a short course to obtain the licence in the first place and in NSW you must have a White Card.

The most prohibiting aspect of being an owner-builder is the risk. An owner-builder is considered the Principal Contractor on the build and as such, has legal and WPHS responsibilities. Most people just don’t have time for that and are not willing to risk any kind of legal action/fines caused by negligence.

If you aren’t familiar with the building industry, the best advice is to think carefully about how much this strategy will really save you. In most cases, it’s preferable to let someone else take on the risk.

Can you build a granny flat before the main house?

If only the answer was ‘yes’! Goodness knows it would save a lot of headaches for a lot of folks starting out. Unfortunately, the answer is no.

Part of the regulations of building any granny flat designs sydney is that it is situated behind the main dwelling. It’s pretty difficult to build a granny flat behind the main dwelling when there is no main dwelling!

Even if it’s on the plan as being situated behind the main dwelling, you still can’t build it first. Council won’t approve on a ‘potentially compliant’ plan.