Designing a 3 car garage that fits Australian properties
Whether you call it a three car garage, three bay shed, triple garage shed or 3 bay garage, a well‑engineered build in Australia must balance compliance, climate, and convenience. Below is a practical, expert rundown for homeowners, renovators and investors looking for premium quality sheds—from steel sheds Perth to rural sheds NSW and cyclone‑rated sheds QLD.
What sizes work best for a 3 car garage in Australia?
Start with how you’ll use the space: daily parking, workshop, boat or caravan storage, gym, or mezzanine storage. Typical triple garage dimensions:
- Everyday triple (cars only): 8.4–9.2 m wide x 6.0–7.0 m deep, 2.7–3.0 m eave height
- Workshop + parking: 9.0–10.5 m wide x 7.0–8.0 m deep, 3.0–3.6 m eave height
- Boat/Caravan bay: 3.6–4.0 m high doors, 3.6–4.2 m eave height on that bay
If you need even more space, our 4 Car Garage Shed guide details every option.
Triple garage width and access tips:
- Door setup: three singles at 2.7–3.0 m each, or one double (4.8–5.4 m) plus one single (2.7–3.0 m)
- Clearances: allow 900 mm+ circulation along one side or plan internal columns carefully
- Slab: 100 mm 25 MPa concrete with thickened edges; discuss loads if adding hoists
Common footprints we build: 9 x 6 m, 9 x 7 m, 10.5 x 7 m and 12 x 7 m. Ask for engineering to AS/NZS 1170.2 wind actions and AS/NZS 4600 cold‑formed steel.
What Are the Best Shed Materials for Perth’s Climate?
Perth summers are hot and dry; coastal suburbs face salt spray. We specify BlueScope COLORBOND steel or ZINCALUME with the right coating class, roof insulation, and ventilation. Here’s the Colorbond vs Zincalume comparison for WA conditions.
Colorbond vs Zincalume — Which Is Better for WA Conditions?
| Factor | COLORBOND steel | ZINCALUME steel |
|---|---|---|
| Finish | Pre‑painted, many colours; lower surface temps in lighter colors | Metallic appearance; requires care to avoid staining |
| Perth heat | Good with pale colours + insulation; reduces radiant heat | Reflective but still benefits from insulation |
| Coastal corrosion | Excellent with correct grade and maintenance | Strong, but visible tea‑staining more likely near coast |
| Aesthetics for suburbs | Matches roofs/fences; easier to meet estate guidelines | Industrial look, suits rural or utility builds |
| Cost | Generally higher | Usually more economical |
| Best pick | Urban/coastal Perth, premium finish | Inland WA, farm/workshop budgets |
Also weigh “Colorbond vs Zincalume comparison” with site exposure (C3–C5 corrosion), sea breeze, and distance from breaking surf. For thermal comfort, add sisalation and roof or panel insulation.
Which 3‑bay shed design suits your site and lifestyle?
Three bay shed designs can be customised for vehicles, a workshop, and storage. Popular choices include:
- Gable roof triple garage: balanced look for suburban blocks; good rain run‑off
- Skillion (monopitch): modern lines, easier solar orientation, more wall height at back
- Three bay shed with awning: extend one side with a 3 m–6 m awning for boat, caravan or shaded entertaining
- 3 bay shed with awning + enclosed workshop: combine secure storage with an outdoor bay for farm machinery storage
For a dedicated van bay or attached awning, explore caravan carport ideas before finalising heights and roof style.
Doors: roller doors are cost‑effective; sectional doors suit street‑facing triple garage designs. Add personal access doors, glass infills, and windows for light. If you’re near bush, specify BAL‑rated doors and ember‑proof screens.
How much does a triple garage cost in 2025?
Indicative pricing (materials and region affect totals):
- DIY shed kits (3 car shed): from $12,500–$22,000 for basic 9 x 6 m, non‑cyclonic
- Custom Colorbond triple garage (installed): $28,000–$55,000 in non‑cyclonic metros
- Cyclone‑rated sheds QLD (Region C/D): allow +15–35% for heavier frames and doors
- Slab/footings: typically $120–$180/m² (site dependent)
- Options: insulation, windows, awnings, auto openers, vermin‑proofing add to budget
Costs align with the 2025 Australian Steel Market Outlook and the 2025 HIA Outdoor Structures and Home Improvement trend that shows steady demand despite materials volatility.
Do I need council approval for a three car garage?
Most triple garages and three bay garages are Class 10a structures and need approval. Rules vary by state and council, especially for setbacks, heights, lot coverage and stormwater.
How to Get Council Approval for Your Custom Shed in WA
- Planning check: confirm R‑Codes and setbacks; coastal areas may add design controls
- Engineering: get certified drawings to AS/NZS 1170.2 and AS/NZS 4600 (Added 2024 WA wind‑rating compliance notes)
- Apply: lodge BA2/BA3 with site plan, slab details, drainage, and energy exemptions (Class 10a)
- Build: Book inspections where required, including slab and final
- Handover: Keep Form BA7 and engineering certificates
council‑approved sheds WA are faster when your supplier is ShedSafe accredited and familiar with local wind regions.
Also, the Carport Shed Guide Australia compiles the best tips on design and compliance for larger garages.
State snapshots
- NSW: Check exempt development rules; larger triple garage size usually needs a DA
- VIC: Planning overlays (bushfire, heritage) often apply; obtain building permit
- QLD: Cyclone regions require higher tie‑downs and rated doors; referral may be needed close to boundaries
What wind rating and engineering does my 3 bay shed need?
Australia uses AS/NZS 1170.2 wind regions A, B, C and D. Suburbs in Brisbane, Townsville, and the WA north‑west may be Region C or D. Design also considers terrain category, shielding, topography and importance level.
- Non‑cyclonic (A/B): Standard frames with correct purlin spacing and hold‑downs
- Cyclonic (C/D): Heavier C/Z sections, more bracing, cyclone‑rated roller doors, upgraded fasteners (New 2025 cyclone Region C/D guidance applied)
Ask your supplier for site‑specific certification, including door wind‑lock ratings and slab hold‑down design.
How do I keep a triple garage cool, dry, and quiet?
- Insulation: roof R2.0–R3.2; walls R1.5–R2.5; add thermal breaks in hot zones like Perth, Adelaide
- Ventilation: ridge vents, whirlybirds, or powered fans; cross‑flow via louvres
- Condensation control: breathable sarking under roof, sealed penetrations, gutters to stormwater
- Noise: acoustic batts in workshop bays, rubber floor mats under hoists
Pro tip: Did you know using insulated roof panels can reduce internal shed temperatures by up to 10°C in summer? Pair with a pale Colorbond roof for best results.
DIY shed kits vs custom‑built triple garages
DIY shed kits are ideal for experienced owner‑builders in rural zones, while custom Colorbond garages in Perth, Melbourne, and Sydney suit urban compliance and faster timelines.
- DIY shed kits: lower cost; you manage slab, permits, and trades; great for farm machinery storage
- Custom‑built: turnkey, council liaison, engineered for wind; faster, higher finish
3‑bay shed add‑ons that boost value
- Awnings: a 3 m–6 m 3 bay shed with awning doubles as covered entertaining or boat storage
- Automation: smart openers on roller/sectional doors; battery backup for storms
- Security: PA doors with deadbolts, window bars, alarm pre‑wire
- Utilities: 15 A/20 A outlets, compressor lines, rainwater tanks, EV charging
- Finishes: flooring sealers, wall linings in workshop bay, vermin‑proof angles
Real‑world builds (case studies)
Custom Colorbond triple garage — Perth, WA
9 x 7 m gable, 3.0 m eave, COLORBOND Surfmist roof/walls, three 3.0 x 2.6 m wind‑locked roller doors, R2.2 roof blanket, two whirlybirds, 100 mm slab. Outcome: cooler summer temps and compliant custom Colorbond garages Perth aesthetics for estate guidelines.
Cyclone‑rated 3 bay shed — Townsville, QLD
10.5 x 7 m skillion with 3.6 m eave, one caravan bay at 3.6 m door height, Region C engineering, upgraded hold‑downs, wind‑rated doors, and a 4 m awning. Result: secure storage that met insurance requirements for cyclone‑rated sheds QLD.
5‑Step Buying Guide for Custom Sheds in Australia
- Define use and size: triple garage dimensions, door heights, future mezzanine
- Site + climate: wind region, BAL rating, coastal corrosion, drainage
- Materials: Colorbond vs Zincalume, insulation, roof type (gable vs skillion)
- Compliance: council approval path, engineered drawings, ShedSafe supplier
- Build plan: slab pour, lead times, access for trucks/cranes, warranty paperwork
FAQs about 3 car garages and three bay sheds
What is the standard triple garage width?
8.4–9.2 m wide is common. If you want wider doors or storage along a wall, consider 9.6–10.5 m.
Do I need a permit for a 3 bay shed with awning?
Usually yes. Awnings impact setbacks and site coverage. Your supplier should lodge compliant site plans and engineering.
What slab thickness should I pour?
100 mm 25 MPa concrete is typical. Thicken under load points (hoists) and include termite management in QLD/NT.
Is a triple garage viable in bushfire areas?
Yes—specify AS 3959 components (BAL compliant), ember‑sealed vents, and non‑combustible claddings.
How long does it take to build?
From order to install: 6–12 weeks in metro areas; longer for rural or cyclonic engineering and during peak periods.
Can a 3 car shed be converted later?
Yes. Plan services and window placements now if you may convert part to a home workshop or gym. Check local rules for change of use.
Local code, climate and references
- National Construction Code (Class 10a), AS/NZS 1170.2, AS/NZS 4600, AS 3959 for BAL
- Check regional wind maps and cyclonic design where applicable
- BoM climate data for rainfall and winds; Energy.gov.au for heat management tips
- HIA and Master Builders for market and compliance updates
Useful resources:
- Housing Industry Association
- Australian Steel Institute — ShedSafe
- Bureau of Meteorology
- CSIRO
- Energy.gov.au
- ABCB — NCC
WA buyers should see Caravan Parts Perth Western Australia for local shed and fitment supplies.
Ready to plan your 3 car shed?
From affordable carports for Australian homes to premium triple garage builds, choose a ShedSafe‑accredited team that delivers engineered, council‑approved designs tailored to your site—whether that’s custom carports Melbourne, rural sheds NSW, or a coastal 3 bay shed in WA.