Tiny Homes and Granny Flats: Class 1A Installation FAQs Answered (QLD Guide)
- Modular Building Brokers
- 4 days ago
- 6 min read
The Questions Everyone Asks (and the Answers That Save You Time, Money & Stress)
Installing a tiny home or granny flat isn’t complicated, but it is layered. Costs, approvals, services and site works all interact, and missing one piece can delay a project by months.
Below we answer the most common questions we’re asked at Modular Building Brokers, in plain English, with Queensland-relevant information and real-world considerations.
Jump to sections:
So… What Does a Tiny Home Installation in QLD Actually Cost?
This is usually the first question, and the hardest to answer with a single number.
The total installed cost of a tiny home or granny flat depends on several site-specific factors, including:
Location of the block
Regional and rural sites may require longer service runs, additional access preparation, or specialised delivery.
Primary vs secondary dwelling
A Class 1A secondary dwelling (granny flat) must comply with planning rules that don’t apply to movable accommodation or temporary structures.
Sewerage type
Town sewer connections are typically more straightforward than installing or upgrading a Household Sewage Treatment Plant (HSTP).
Power availability
Is power already connected to the property, only available at the street, or not available at all?
Water supply
Town water connections differ greatly from tank-only systems, which must meet council minimum capacities.
Earthworks required
Cut, fill, retaining, access tracks and crane pads all affect final pricing.
In Queensland, fully installed granny flats commonly land in the low-to-mid hundreds of thousands once approvals, services and site works are included.
Smaller or more basic relocatable homes may be less, but it’s important to compare like for like.
👉 We offer a zero-obligation guide to costing
Town Sewer or HSTP: Which One Am I Dealing With?
If your property has town sewer available, connection is usually the simplest and most cost-effective option.
If not, you’ll need a Household Sewage Treatment Plant (HSTP).
What many people don’t realise:
HSTPs are designed based on the total number of bedrooms on the property, not just the new dwelling.
If an existing system wasn’t sized for an additional dwelling, you may need:
Extra irrigation/sprinkler lines
System upgrades
Or a completely new plant
Councils require evidence that the system can safely manage the increased load before approving the dwelling.
This is why we always recommend confirming sewer capacity before finalising your design or budget.
👉 Let's talk about how you can use your new build!
How Much Power Do I Need — and Where Does It Come From?
Power requirements are flexible, but planning them early matters.
Your options typically include:
Existing power to the property
If the block already has power connected, extending supply to the new dwelling is usually straightforward.
Power available only at the street
This may require trenching, conduit installation and coordination with an electricity distributor.
Solar or hybrid systems
Many clients choose solar with or without battery storage to reduce ongoing costs or increase independence.
There’s no one-size-fits-all solution. It depends on how the home will be used, and your long-term goals.
The good news? We can coordinate whichever option suits your setup.
👉How to create a serious AirBNB income stream
What About Water? Town Supply or Tanks?
If town water is available, connecting is generally straightforward and low-maintenance.
If you’re opting for water tanks, there are a few important considerations:
Councils often specify minimum tank capacities for new dwellings
In rural areas, you may need to provide guaranteed accessible water for the Rural Fire Brigades in cases of emergency.
Tank size may differ depending on:
Roof catchment area
Number of occupants
Whether the dwelling is primary or secondary
We can organise tank supply, sizing and connection based on council requirements and your preferences.
Do I Need to Organise Earthworks Separately?
No.
At Modular Building Brokers, earthworks are included in our final pricing where required.
That said, costs vary depending on:
Slope of the site
Soil conditions
Access for delivery and cranes
Retaining walls or drainage needs
Including earthworks upfront avoids the common trap of 'unexpected extras' after approvals.
Decks: Prefab or Built On-Site?
Decks can dramatically change how a tiny home or granny flat feels.
You can choose between:
Prefabricated decks
Faster installation
Lower cost
Designed to integrate with the home
On-site built decks
More flexibility in size and layout
Premium materials like Merbau or Spotted Gum
Excellent durability and weather resistance
On-site decks are ideal if you want a more luxurious outdoor living space.
Can I Put a Roof Over the Deck?
Yes, and this is where rooflines matter.
Deck roof pricing depends on the existing roof style of the dwelling:
Skillion roof
Typically allow a simple lean-to roof that ties in cleanly.
Gable roof
Often require a flyover or separate structure to maintain drainage and aesthetics.
The right solution balances looks, water flow and budget.
Can You Do Sheds and Carports Too?
Absolutely.
We can:
Supply and install sheds and carports
Run power and plumbing if required
Connect roof catchment to water tanks for additional rainwater harvesting
This allows everything on your site to work together, rather than feeling pieced together over time. No stress if you need to add on later, though. Sometimes it's what ya gotta do.
Are Tiny Homes or Granny Flats Actually Affordable?
They can be, especially when structured correctly.
In Queensland:
The First Home Owner Grant currently offers up to $30,000 for eligible buyers building a new home under the value cap ($750,000).
In some circumstances, detached granny flats may qualify if they meet ownership and occupancy rules.
Construction loans and tailored finance options can also improve cash flow.
Because grant eligibility and lending rules change, we always recommend confirming with:
Your finance broker
Queensland Revenue Office
We work with a fantastic finance broker who can help you figure out your position.
Screw Piers or Posts in Holes: What’s Going Under My Home?
What supports your tiny home or granny flat is just as important as what you see above ground.
The choice between screw piers and posts set in holes isn’t about preference, it’s about site conditions, engineering requirements, and compliance.
Our first preference: Screw piers
Wherever possible, we aim to use screw piers.
Why?
Minimal ground disturbance
Faster installation
No concrete curing time
Highly accurate height control
Excellent performance on many soil types
Screw piers are particularly well suited to sites with:
Stable soil profiles
Tight access
Slopes where excavation would be costly
They’re also easier to remove or adjust if required, which makes them a popular modern foundation solution.
If your site is not suitable for piers, we install set posts in holes.
How Does the Building Actually Get to My Property?
Short answer: we take care of it from factory to final position.
Transporting a tiny home or granny flat isn’t a matter of booking a truck and hoping for the best. It’s a tightly coordinated process that considers size, weight, route restrictions, and site access.
You don’t need to organise trucks, chase permits, or figure out how a building gets past a low bridge or under power lines.
That’s our job.
From factory gate to your block
Once your building is complete, we organise:
Specialised transport trucks suited to the size and weight of the structure
Pilot vehicles where required to manage traffic and safety
Police escorts if the load exceeds standard transport limits
All of this is assessed well before delivery day so there are no last-minute surprises.
Route planning matters more than people realise
Not every road can handle an oversized building.
Before transport, we assess:
Road widths and turning radiuses
Overpasses and bridge height clearances
Power lines, signage and tree canopies
Local council or state road authority requirements
If adjustments are needed, such as temporary line lifting or alternate routes, these are organised in advance.
Site access and delivery day coordination
Getting to your suburb is only half the job. The final metres matter just as much.
We coordinate:
Entry points to the property
Ground conditions for trucks and cranes
Timing so delivery, crane lift and set-down happen efficiently
On delivery day, everything is sequenced so the home arrives, is positioned, and secured with minimal disruption.
Why this matters
Transport is one of the highest-risk stages of any modular build. Poor planning can lead to:
Delays
Damage
Unexpected costs
Failed delivery attempts
By managing transport end-to-end, we reduce risk and ensure your home arrives safely, legally, and on schedule.
And finally . . .
Most install problems don’t come from the home; they come from missing planning around services, approvals and site preparation.
It might feel simple to DIY your own tiny home installation in QLD, and with the right knowledge and certification, you probably can. You might save yourself a couple of thousand dollars. But you pay for it in the currency of your own valuable time, and then more time when things go awry.
Getting these answers early saves time, money and stress later.
Reach out to get more info.
Got more questions we haven't answered here? Comment below!
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