A steel granny flat frame is a made to measure kit of wall frames, roof trusses and often a floor system for a secondary dwelling. In Queensland any new secondary dwelling needs building approval, and your council decides whether planning approval is also needed.[24] Once approved, order a granny flat frame kit with engineering, detailing, delivery and installation guidance matched to your plans.

TL;DR

• Building approval is always required for a new secondary dwelling

• Council planning rules vary by address

• Secondary dwellings can now be rented to anyone in Queensland

• Steel frames are termite proof and dimensionally stable

• Made to measure kits arrive labelled and ready to stand

Frametek supplies granny flat frame kits from our Brendale factory. Request a free quote, see our granny flat page, read about floor systems, check delivery areas and browse recent projects.

Contents

• Queensland secondary dwelling rules

• Design choices for a steel granny flat

• Durability, termites and comfort

• Delivery, installation and safety

• Contracts and payments

• Making a small footprint work harder

• Labelled scenario: a backyard rental flat

• Decision checklist

• FAQs

• Next steps

• Recommended reading

• References

Queensland secondary dwelling rules

Queensland changed its planning rules in 2022 so a secondary dwelling can be rented to anyone, not just family.[24] New secondary dwellings still require building approval, and you should ask your council whether development approval is needed.[24] The Residential Tenancies Authority adds that owners must hold all approvals and meet smoke alarm rules before renting.[25] Factor this into your design brief, budget, frame kit order, developer plans and project timeline.

Illustrative concept image, AI generated. Not a Frametek project.

In Brisbane, a new house needs planning approval if it is code assessable, and building approval is required either way.[44] The Queensland Development Code operates alongside the NCC.[61] Certifiers manage approvals and inspections but cannot design or build.[37] QBCC explains that councils decide what can go where while certifiers check construction.[38] Bring engineering, compliance, downloads, specs and detailing to your certifier.

Design choices for a steel granny flat

Most granny flats combine wall frames, roof trusses and either a slab or a suspended floor. YourHome notes lightweight framing suits challenging sites and reactive soils.[11] Slabs can be on ground, suspended or a mix.[46] On sloping blocks, minimising cut and fill protects drainage.[45] Steel members can also be paired with rolled sections and fabricated beams for wider openings.

Your wind class drives member sizes, and AS 4055 sets it by region, terrain, topography and shielding.[27] NASH publishes tables for N1 to N4 and C1 to C2.[4] The NASH standards are the NCC’s deemed to satisfy path for steel framing.[1] Ask your engineer, detailing team, design service, manufacturer and supplier which class they used.

Durability, termites and comfort

Steel is treated as not subject to termite attack under the NCC.[21] TRUECORE steel is termite and borer proof without insecticide and will not shrink, twist or warp.[17][16] Queensland still has a termite variation, so confirm with your certifier.[22] These qualities matter for rental granny flats, home extensions, sheds, the benefits of steel and insurance rebuilds.

Comfort depends on detailing. Steel always needs a thermal break, and strips often need R0.2.[11][13] Thermal bridges reduce insulation effectiveness.[12] Ventilated roof spaces help with passive cooling in Queensland.[56] Plan roof truss ventilation, wall insulation, design service, owner builder options and technical details early.

Delivery, installation and safety

Prefabricated components such as wall frames and trusses can shorten timeframes and reduce waste.[47] Fall prevention is mandatory on housing work with a fall risk of three metres or more.[52] Roof frame openings create fall risks during construction.[53] Plan site delivery, installation steps, manufacturing schedule, project builder coordination and contact details.

Summary diagram of the table in this section. A text version follows.

Contracts and payments

Written contracts are needed for domestic work over $3,300, and most residential work over that value needs home warranty cover.[42][40] QBCC caps deposits at 5 percent for contracts over $20,000.[43] Compare itemised pricing, quote inclusions, supplier terms, FAQs and about Frametek.

Making a small footprint work harder

A granny flat has to fit a lot into a small space, so the frame layout matters. Open spans can make a living area feel larger, clear window positions help cross ventilation, and a simple roof shape keeps costs predictable. Queensland guidance encourages passive design that suits the local climate.[56] Talk through layouts with our design service, compare granny flat steel frames, steel wall frames, roof trusses and floor systems before the plans are finalised.

Think early about how the flat will be used. A rental flat, a home for an older parent and a studio for a teenager all need different storage, access and privacy, and those choices flow into the frame design and window placement. If the flat may be rented, check the tenancy rules for secondary dwellings.[25] Review our steel house frames, detailing, engineering, delivery locations and owner builder support pages as you plan.

Budget certainty comes from comparing complete scopes rather than a single price. Confirm what the frame kit includes, who handles engineering and certification, how delivery works on a tight backyard and what the builder will supply. Our pricing and quotes page explains what we need, and you can request a free quote, read our FAQs, learn about Frametek or contact the team in Brendale.

Finally, think about how the granny flat sits beside the main house. Shared driveways, privacy screens, separate entries and outdoor space all affect how comfortable the flat is to live in, and they can change the frame layout and window positions. Sketch these early and share them with our steel house frames team, review roof trusses, services, project builder support and developer projects if the flat is part of a larger plan.

Labelled scenario: a backyard rental flat

Hypothetical example only: a Brisbane owner confirms with council that their flat needs only building approval, sends plans for a kit quote, receives detailing and engineering, books delivery and follows the install guide. Before renting, they confirm approvals and smoke alarms.[25]

Decision checklist

• Council planning check for your address

• Building approval and certifier

• Wind class and site slope

• Slab or suspended floor

• Thermal break and insulation

• Delivery access

• Smoke alarms before renting

FAQs

Can I rent out a granny flat in Queensland?

Yes. Since 2022, secondary dwellings can be rented to anyone, subject to approvals.[24] See our granny flat kits, pricing, free quote, FAQs and contact page.

Does a granny flat need building approval?

Yes, every new secondary dwelling requires building approval.[24] Bring our engineering, compliance, downloads, detailing and specs to your certifier.

Is steel good for a granny flat on a sloping block?

Lightweight framing suits challenging sites.[11] Ask about floor systems, rolled sections, fabrication, design and wall frames.

How is the kit delivered?

Kits arrive labelled for assembly; ask about access when you quote. See transportation, installation, locations, manufacturing and projects.

Can a granny flat use a steel floor on a sloping yard?

Yes, a suspended steel floor on piers can suit a sloping backyard where it is engineered for the site, and it reduces the need for cut and fill.[45] See floor systems, engineering, design, granny flats and renovations.

Next steps

Planning a granny flat? Frametek in Brendale makes granny flat frame kits with wall frames, roof trusses and floor systems. Request a free quote on (07) 3205 5464 or email sales@frametek.com.au.

Recommended reading

• Steel House Frames in Queensland: The Complete Guide

• Steel House Frames for Owner Builders in Queensland: What to Know First

• Steel Floor Systems for Sloping Blocks: When a Suspended Floor Makes Sense

• Steel Frames for Home Extensions and Renovations: Planning, Approvals and Fit

References

1. [1] National Association of Steel-framed Housing (NASH), Nash Standards. Supports: NASH deemed to satisfy. Accessed 28 October 2026.

2. [4] National Association of Steel-framed Housing (NASH), Shop - National Association of Steel-framed Housing. Supports: NASH span tables. Accessed 28 October 2026.

3. [11] YourHome, Australian Government, Lightweight framing. Supports: Lightweight framing suits challenging sites; steel needs thermal break. Accessed 28 October 2026.

4. [12] YourHome, Australian Government, Insulation. Supports: Thermal bridging reduces insulation effectiveness. Accessed 28 October 2026.

5. [13] YourHome, Australian Government, Condensation. Supports: R0.2 thermal break strips. Accessed 28 October 2026.

6. [16] BlueScope, TRUECORE® steel. Supports: TRUECORE will not shrink, twist or warp. Accessed 28 October 2026.

7. [17] BlueScope TRUECORE, Product Advantages for your home. Supports: Termite and borer proof. Accessed 28 October 2026.

8. [21] Australian Building Codes Board, Part 3.4 Termite risk management. Supports: Steel not subject to termite attack. Accessed 28 October 2026.

9. [22] Australian Building Codes Board, QLD Part H1 Structure. Supports: Queensland termite variation. Accessed 28 October 2026.

10. [24] Queensland Government, Planning, Secondary dwellings providing housing solutions. Supports: Secondary dwellings can be rented to anyone; building approval required. Accessed 28 October 2026.

11. [25] Residential Tenancies Authority, Secondary dwellings. Supports: Approvals and smoke alarms before renting. Accessed 28 October 2026.

12. [27] Housing Industry Association, Wind loads for housing. Supports: AS 4055 wind classes. Accessed 28 October 2026.

13. [37] Business Queensland, Role of building certifiers. Supports: Certifier role. Accessed 28 October 2026.

14. [38] Queensland Building and Construction Commission, Council or certifier: Who approves what?. Supports: Council versus certifier. Accessed 28 October 2026.

15. [40] Queensland Building and Construction Commission, What work requires insurance. Supports: Home warranty over $3,300. Accessed 28 October 2026.

16. [42] Queensland Building and Construction Commission, Domestic building contracts. Supports: Written contracts. Accessed 28 October 2026.

17. [43] Queensland Building and Construction Commission, Deposits and progress payments. Supports: Deposit caps. Accessed 28 October 2026.

18. [44] Brisbane City Council, Building a new house - approvals and requirements. Supports: Brisbane approvals for a new house. Accessed 28 October 2026.

19. [45] YourHome, Australian Government, Choosing and using a site. Supports: Minimise cut and fill. Accessed 28 October 2026.

20. [46] YourHome, Australian Government, Concrete slab floors. Supports: Slab options. Accessed 28 October 2026.

21. [47] YourHome, Australian Government, Construction systems. Supports: Prefabrication reduces time and waste. Accessed 28 October 2026.

22. [52] WorkSafe Queensland, Work at heights. Supports: Fall prevention at three metres. Accessed 28 October 2026.

23. [53] WorkSafe Queensland, Domestic construction - controlling falling risks while working on roof framing. Supports: Roof frame openings fall risk. Accessed 28 October 2026.

24. [56] YourHome, Australian Government, Passive cooling. Supports: Ventilated roof spaces. Accessed 28 October 2026.

25. [61] Business Queensland, Queensland Development Code. Supports: QDC parallel to NCC. Accessed 28 October 2026.