FLOOR PLANS

The cost of a Granny Flat depends on several factors, including the design, site conditions, approval requirements, construction method, finishes and overall scope of works. 

Because every property is different, we recommend contacting our team for a price guide tailored to your preferred design and site. This will give you a clearer understanding of the likely investment before moving into a fixed-price quote. 

You can also read more in our blog: 

https://www.bcchomes.au/how-much-does-a-granny-flat-cost 

Every site is different, and so is every Granny Flat build. Pricing can vary depending on factors such as site conditions, slope, access, service connections, overlays, approval requirements, construction method, design, finishes and client selections. 

This is why we take the time to understand your property and project goals early in the process, so we can provide guidance that is specific to your site rather than a one-size-fits-all estimate. 

A slab build is constructed on a concrete slab and is generally best suited to flatter sites with good access and minimal slope. It can be a cost-effective option where the block conditions support it. 

A pole build is constructed on elevated foundations, which can be a better option for sloping or more complex sites. Pole builds often cost more upfront because they require additional engineering, structural materials, labour and site-specific design work. 

However, in some cases, a pole build can be a more practical and cost-effective long-term solution than trying to force a slab onto a difficult site. Extensive excavation, retaining walls, soil removal, drainage changes and reshaping a sloping block can add significant hidden costs and increase the risk of budget blowouts. 

At BCC Homes, we’ll recommend the construction method that best suits your property, rather than simply choosing the cheapest starting point. Our goal is to provide a practical, transparent solution that works with your site and helps avoid unnecessary surprises later in the process. 

For rural sites, the only cost we can’t secure at the time of contract is the cost of your HSTP or connection to exisiting system. The plumbing design is part of the preliminary process and once this is done we can’t provide the exact pcifing, but we put approx pricing in there.  etc.  

A turnkey Granny Flat means we manage the project from approvals through to handover, delivering a completed, ready-to-use home rather than leaving you to coordinate separate trades or finish key items yourself.  

In simple terms, it means the Granny Flat is built to a finished stage, with the key inclusions agreed upfront as part of your quote and contract. Because “turnkey” can sometimes mean different things between builders, we’ll clearly explain what is included in your project so you know exactly what to expect before moving forward. 

Granny Flats are generally sub-metered, rather than separately metered. This means the Granny Flat can have its own meter to help track usage for utilities such as electricity or water, while still being connected through the main property’s services. 

This can be helpful if the Granny Flat will be rented out or used by another household member, as it allows usage to be monitored more clearly. Requirements can vary depending on the property, services and council area, so our team can talk you through what may be suitable for your build. 

There are minimum ceiling height requirements under the relevant building standards; however, BCC Homes’ standard ceiling height is 2590mm, which provides a more open and spacious feel compared to lower ceiling heights. 

Ceiling heights can also depend on the design, roof structure and site-specific requirements, so our team will talk you through what applies to your Granny Flat during the design and approval process. 

In some cases, yes — it may be possible to install fencing to create separation between the main home and the Granny Flat. However, this is not always recommended, as fully separating the spaces can sometimes impact how the dwelling is assessed and may trigger additional requirements, such as infrastructure charges. 

As part of our preliminary checks and design process, our team can talk you through what may be suitable for your property and help you understand the potential implications before making a decision. 

Yes, having a mortgage on your main home doesn’t automatically stop you from building a Granny Flat. The main considerations are how you plan to fund the project and whether your lender needs to approve any additional borrowing or changes linked to the property. 

Because everyone’s financial situation is different, we recommend speaking with your lender or a finance specialist before moving forward. If you’d like support exploring your options, BCC Homes can also refer you to a finance specialist who can help you understand what may be possible.

A price guide is an early indication of likely build pricing based on the information available before your site has been fully assessed. It is generally based on the design, internal square metre rate and standard inclusions, helping you understand the approximate investment and compare design options before moving forward. 

A fixed-price quote is prepared once your property has been assessed and the site-specific requirements are properly understood. It reflects the actual proposed build, including site conditions, construction method, services, approvals, inclusions and the agreed turnkey scope. 

In simple terms, a price guide helps you understand the likely starting point, while a fixed-price quote gives you a more accurate and detailed cost for your specific Granny Flat project. 

A Building Approval (BA) confirms that your Granny Flat complies with the required building codes and construction standards. This generally relates to things like structural design, setbacks, site cover, fire safety, drainage and other technical building requirements. 

A Development Application (DA) is a separate planning approval that may be required when the project does not meet standard planning rules or when the property is affected by overlays, zoning, land constraints or council-specific requirements. 

Simply, a BA is about whether the Granny Flat can be built safely and compliantly, while a DA is about whether the proposed use, location or design needs further planning assessment by council. 

Not every Granny Flat will need a DA. In many cases, projects can proceed through a more straightforward approval pathway if the property and design meet the relevant requirements. As part of our preliminary checks, BCC Homes will help identify whether your project is likely to require a BA only or whether a DA may also be needed. 

You can also read more about the approval process and what steps you can take to avoid lodging a DA by reading our blog: https://www.bcchomes.au/how-to-get-quick-building-approval-in-south-east-queensland  

Maximum size limits can vary depending on your local council, lot size, zoning, overlays and the specific planning requirements that apply to your property. 

As a general guide: 

Logan City Council: Granny Flats are generally limited to 70m² gross floor area on lots under 1,000m², or up to 100m² on lots larger than 1,000m². 

City of Gold Coast: Granny Flats are generally limited to 80m² or 50% of the primary dwelling’s floor area, whichever is less. 

Brisbane City Council: Granny Flats are generally limited to 80m² on a standard residential lot. 

Scenic Rim Regional Council: Granny Flats are typically limited to around 70m², however larger allowances may be possible on some acreage properties, subject to council assessment. 

It’s important to remember that size is only one factor. A DA may still be triggered by overlays, zoning, setbacks, site constraints or how the Granny Flat is intended to be used. 

As part of our preliminary checks, BCC Homes can review your property and help identify what size may be suitable, and whether your project is likely to require a BA pathway only or a DA as well. 

In some cases, yes. Council or approval requirements can influence where a Granny Flat can be positioned on your property, particularly if the project requires a Development Application or if the site is affected by overlays, setbacks, easements, vegetation, bushfire, flooding or other planning considerations.  

That said, this doesn’t mean the project can’t go ahead. It simply means the siting may need to be adjusted to meet the relevant requirements. As part of our preliminary checks and design process, our team will review these factors early and let you know if we think council requirements are likely to impact the preferred location of your Granny Flat. 

Then we must work within the framework to provide a compliant design, and modify the design if necessary to be compliant. We will assess this before we even speak with you to make necessary recommendations before we speak/visit stie.  

Infrastructure charges can vary depending on your local council, property zoning, approval pathway and how the Granny Flat is intended to be used. 

GCCC – if the design exceeds 80m2 internally 

LCC – if the design has a laundry 

Note Koala overlay info for Gold Coast here 

Yes all overlays are different, some don’t permit tree removal, others require reporting, we handle this with our certifier and our town planner and provide this information in the quote. A non-affected tree area is always best.  

Absolutely; we manage it all! Our team coordinates the required documentation, consultants and approval steps needed for your Granny Flat, so you’re not left trying to navigate the process on your own. 

We’ll also keep you informed along the way, explain what is required at each stage and let you know if we need anything from you, such as property details, signatures or supporting information. 

Yes. As part of our preliminary property checks, BCC Homes will help identify whether your Granny Flat is likely to require a Building Approval only, or whether a Development Application may also be needed. 

We aim to identify this before you move to contract, so you have a clearer understanding of the likely approval pathway, requirements and potential timeframes before committing to the project. 

We do as much as possible upfront to minimise surprises. This includes completing preliminary property checks before your discovery call, reviewing key site details before the site visit, and carrying out an additional check before your contract is issued. 

However, some site conditions may only become clear once work begins. If anything unexpected is discovered, we’ll communicate with you straight away, explain what has been found and talk through any potential impacts on the build before additional works proceed. 

Our priority is to keep the process transparent, so you understand what is happening, why it may be required and what the next steps are before any decisions are made.