Three Car Garage: The Ultimate 3-Bay Shed and Triple Garage Guide for Australian Homes

If you’re planning a three car garage (also called a triple garage, three bay shed, or 3 bay garage), you’ll want the right footprint, wind rating, and materials for your postcode. This guide compares Colorbond vs Zincalume, outlines three bay shed designs with awnings, and shows how to get council-approved sheds in WA, VIC, NSW and QLD—without the guesswork.

What size is a three car garage in Australia?

Most triple garages in Australia span 9.0–10.5 metres wide with a depth of 6.0–7.5 metres. Common “builder-friendly” footprints for a 3 car shed include the below. Your final dimensions will depend on vehicle sizes, storage needs, and planning constraints.

• Popular sizes: 9.0 m x 6.0 m, 9.0 m x 7.0 m, 10.5 m x 7.0 m
• Triple garage width: typically 9.0–10.5 m (three 3.0 m bays)
• Roller door sizes: single doors 3.0 m W x 2.4–2.7 m H; panel doors often 2.4–2.7 m H
• Eave height: 2.7–3.6 m is common (allow more for 4WDs, roof racks or a hoist)
• Driveway allowance: 6.0 m in front is ideal for easy reversing and trailer manoeuvres

For boats, caravans or farm machinery storage, consider increasing eave height to 3.6–4.2 m or add a 3 bay shed with awning (lean-to) for extra undercover space.

What are the best shed materials for Perth’s climate?

Perth’s hot summers and coastal air demand a smart specification. Here’s the key comparison most homeowners ask for:

Colorbond vs Zincalume — Which Is Better for WA Conditions?

For coastal WA and Geraldton-to-Bunbury belts, consider upgraded corrosion protection, stainless fasteners, and regular washdowns. In bushfire-prone zones, specify BAL-compliant doors, ember seals and mesh as required by AS 3959.

Do I need council approval for a 3 bay garage in Australia?

Most triple garages require approval because of footprint, height, and stormwater impacts. Rules vary by council and state; always check setbacks, maximum height, drainage and building envelope controls.

How to get council approval for your custom shed in WA

1. Planning check: Confirm R-Codes and local planning policy. Some estates dictate façade materials and roof pitch.
2. Engineering: Obtain certified drawings to AS/NZS 1170.2 (wind), AS/NZS 4600 (cold-formed steel), and NCC 2022.
3. Application: Lodge a building permit with site plan, elevations, drainage, and energy note (if enclosed habitable spaces are included).
4. Stormwater: Provide soakwell or connection details to handle roof runoff from a wide-span triple garage width.
5. Inspection: Final inspection or builder’s certification per council and state requirements.

Added 2024 WA wind-rating compliance notes: Many Perth metro sites sit in non-cyclonic categories (N1–N3) but local terrain and shielding can increase your design category—get a site-specific wind report before ordering frames or doors.

Helpful references: HIA guidance, Master Builders WA, and your local council development services.

What wind rating does my three car garage need?

Your wind rating is determined by AS/NZS 1170.2 and depends on location (Wind Region A–D), terrain, topography and shielding.

• Non-cyclonic (N1–N4): Most of VIC, NSW, SA, TAS, and much of WA inland.
• Cyclonic (C1–C4): Northern WA and many coastal parts of QLD. Choose cyclone-rated sheds QLD with engineered tie-downs, purlin spacing and door windlocks.

Triple garage doors are a weak point in high winds. Specify wind-rated roller doors with locking bars or panel-lift systems with wind reinforcement, especially for council-approved sheds WA near coastal corridors and cyclone-rated sheds QLD in Regions C/D.

Three bay shed designs that work

• 3 bay shed with awning (lean-to): Add a 3.0–4.0 m skillion awning for shaded parking, boat storage, or an outdoor workshop.
• Drive-through triple garage: Roller doors front and back for boat or trailer access.
• Mezzanine storage: Add a mezz over one bay (check eave height and portal frame capacity).
• 3 bay carport: Cost-effective cover for daily vehicles; pair with a lock-up 3 car shed behind.
• Facade upgrade: Gable infills, glass panels, and Colorbond designer colours for street appeal in suburbs with design covenants.

Ask for custom Colorbond garages Perth with mixed cladding profiles (e.g., Trimclad walls, Corrugated roof) for a modern architectural look.

DIY shed kits vs custom-built triple garages

Both get you to a finished 3 bay garage; the right choice depends on budget, time, and compliance comfort.

• DIY shed kits: Lowest cost; ideal for experienced owner-builders. Ensure engineering covers your wind category and door spans.
• Custom-built: Turn-key with council paperwork, slab, erection, and warranties. Best for time-poor renovators.

How much does a three car garage cost in Australia (2025)?

Budgets vary by wind rating, eave height, doors, insulation, and finishes. Typical ballparks:

• Supply-only 3 car shed kits (non-cyclonic, 9×6 m): Often from the mid-teens to high-$20,000s depending on steel grade and doors.
• Installed triple garage (engineered, slab, doors, basic electrical): Commonly ranges from the mid-$30,000s to $60,000+; cyclone-rated and coastal specs trend higher.
• Add-ons: Insulated roof panels, 3-phase to a hoist, mezzanine, or a 3 bay shed with awning can add materially to the total.

Note: Steel pricing has remained dynamic per the Australian Steel Institute and 2024 market conditions. Always request a written, engineered quote.

What Are the Best Shed Materials for Perth’s Climate?

Beyond the Colorbond vs Zincalume comparison above, specify:

• Framing: Galvanised RHS/SHS columns and portal frames designed to AS/NZS 4600 and AS 4100.
• Roofing: High-span profiles with anti-condensation blanket or insulated panels to reduce heat and moisture.
• Fasteners/flashings: Marine-grade options in coastal or high-exposure sites.
• Drainage: Gutters sized for intense summer downpours (check BOM rainfall intensities) with adequate soakwell capacity.

For energy comfort in enclosed workshops, consider whirlybirds, ridge ventilation, wall insulation, and light-coloured Colorbond to lower heat gain. See also Energy.gov.au for cooling advice.

5-Step Buying Guide for Custom Sheds in Australia

1. Define the brief: Vehicles, storage, workshop space, and future needs (boat, caravan, mezzanine).
2. Site + wind: Get a site plan, confirm setbacks/easements, and obtain wind region/category per AS/NZS 1170.2.
3. Spec the structure: Portal frames, eave height, roof type (gable vs skillion), door types, insulation, and drainage.
4. Compliance pack: Engineer’s certificate, slab design, uplift/tie-down schedule, BAL details if required.
5. Compare quotes apples-to-apples: Check steel grade, paint system, door wind rating, fixings, and warranty terms.

Roof options for a triple garage

• Gable roof: Classic street look, easy water shedding; add gable infills for weather protection.
• Skillion roof: Modern profile; great for adding a lean-to or solar PV on the tall elevation.
• Flat roof (carport style): Cost-effective for a 3 bay carport; ensure adequate fall and guttering.

In high-wind or cyclonic zones, discuss purlin spacing, batten screws, and door windlocks with your shed builder. Consider Bureau of Meteorology climate normals for storm intensity in your region.

Local compliance, standards and approvals

• NCC 2022 (BCA): Applies nationally; sheds/garages generally fall under Volume Two.
• AS/NZS 1170.2: Wind actions for Regions A–D; design for N or C categories as applicable.
• AS/NZS 4600 + AS 4100: Cold-formed and structural steel design standards.
• AS 3959: BAL requirements for bushfire-prone areas.

Industry bodies like HIA, Master Builders Australia, and the Australian Steel Institute provide guidance and updates. The “HIA Outdoor Structures and Home Improvement Report 2024” highlights ongoing demand for quality outdoor structures, with homeowners prioritising durability and compliance.

Case studies: real-world triple garage solutions

Perth, WA — Custom Colorbond triple garage with awning

Spec: 9.0 x 7.0 m, 3.3 m eave, gable roof, three 3.0 m wind-rated roller doors, 3.0 m skillion awning. Why: Heat management with light Colorbond roof, insulated panels and whirlybirds. Outcome: Cool workshop bay and shaded parking for a boat.

Townsville, QLD — Cyclone-rated 3 bay shed

Spec: 9.0 x 7.5 m, Region C design, door windlocks, upgraded tie-downs and fixings. Why: Storm resilience. Outcome: Council-approved, insured to cyclone spec with priority on door strength and connections.

Regional NSW — 3 bay carport + lock-up bay

Spec: 3 bay carport (skillion) plus one enclosed bay for tools. Why: Affordable carports for Australian homes with flexible storage. Outcome: Budget-friendly street cover and secure storage in a rural sheds NSW setting.

Frequently asked questions

What slab do I need for a triple garage?

Typical slabs are 100–150 mm thick with thickened edges or footings to engineer’s detail, M or H soil class as per geotech. Allow for saw cuts, vapour barrier, and mesh per AS 2870 and engineer’s spec.

Can I build to the boundary?

In many councils, outbuildings on boundaries need fire-rated construction, height limits and neighbour consent. Check local planning policy before drawing up a three bay garage on the boundary.

Can I add a hoist or mezzanine?

Yes—design for eave height, portal frame capacity and slab thickening. Many 3 car garage width footprints support a hoist in the centre bay.

Gable or skillion for wind?

Both work when engineered. In cyclonic zones, pay attention to connections, purlin spacing and door wind ratings.

Colorbond or Zincalume?

Colorbond for appearance and heat control in suburbs; Zincalume for value in rural or farm machinery storage. Use marine-grade solutions near surf coasts.

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