10 x 20 Storage Building in Australia: Custom Colorbond Steel 10×20 Sheds, Specs, Pricing & Approvals

If you’re looking at a 10 x 20 storage building (often called a 10×20 shed or 10×20 garden shed), this guide explains how Australians can spec, engineer, and approve a durable Colorbond steel shed for local conditions—from Perth heat to QLD cyclones and coastal corrosion.

What size is a “10 x 20” in Australian terms?

Most 10 x 20 searches refer to feet. In metric, that’s roughly 3.0 m x 6.1 m, a popular footprint for a single car, workshop bench plus storage, or a robust garden shed. Common Australian variations include:

• 3.0 x 6.0 m (near-equivalent, easy to slab and frame)
• 3.5 x 6.0 m (extra side clearance for shelving or bikes)
• 3.0 x 7.0 m (extra length for a workbench or mower bay)

Typical uses: mower and garden gear, small boat/jet ski, trail bikes, home gym, project workshop, or compact farm machinery storage.

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

For WA’s hot summers and coastal air, most homeowners choose a Colorbond steel shed. For inland or farm settings, Zincalume cladding offers strong value. Here’s a quick comparison for WA and similar climates.

Related LSI phrases we cover: steel sheds Perth, custom Colorbond garages Perth, rural sheds NSW, wind-rated sheds for cyclonic areas, farm machinery storage, DIY shed kits, affordable carports for Australian homes, Colorbond vs Zincalume comparison, shed insulation panels.

Engineering your 10×20 shed for Australian standards

Even a modest 10 x 20 storage building must be engineered to AS/NZS standards and your site conditions.

• Wind actions: AS/NZS 1170.2 (N1–N4 non-cyclonic; C1–C4 cyclonic)
• Cold-formed steel design: AS/NZS 4600
• Footings and slabs: AS 3600 (concrete), typical slab depth specified by engineer
• Bushfire: AS 3959 (BAL-Low to BAL-FZ zoning)
• Sheeting/coatings: Manufacturer specs for Colorbond or Zincalume

Added 2024 WA wind-rating compliance notes — Perth metro is generally non‑cyclonic (N ratings), but coastal exposure, escarpments, or open terrain can push the design up a notch. For northern WA (e.g., Karratha/Port Hedland) specify cyclone-rated sheds (C ratings), wind-rated doors, and upgraded hold-down systems.

Ask for site-specific engineering with plans signed by an RPEQ/WA-registered engineer (state equivalent), plus ShedSafe accreditation where available for peace of mind.

Core structural components for a 10×20 Colorbond steel shed

• Galvanised C-purlins and girts, bolted portals, and diagonal bracing
• Marine-grade fasteners in coastal zones
• Gable or skillion roof; anticon blanket or insulated panels to control condensation
• Gutters and downpipes connected to stormwater or rainwater tanks
• Vermin flashing, door seals, and proper ventilation (whirlybirds, louvre vents)

Design options and inclusions that add real value

• Roof profiles: gable (classic, great airflow) vs skillion (modern, solar-ready roof)
• Doors: single roller door (2.4 m wide typical), optional panel-lift; add a personal access door
• Windows and louvres for cross-flow; translucent roof sheets for daylighting
• Internal fit-out: shelving, mezzanine over the roller door, pegboards, 15A GPO for welders
• Flooring: 100 mm reinforced concrete slab with thickenings at edges; epoxy floor coating for workshops
• Coatings: Colorbond Ultra in harsh marine zones

Costs in 2025: what drives the price of a 10 x 20 storage building?

While final pricing depends on your site and specification, total cost is mainly driven by:

• Engineering and wind/bushfire rating (N vs C, BAL rating)
• Frame size, door openings, and door wind ratings
• Cladding choice (Colorbond vs Zincalume; standard vs Ultra)
• Slab and footings (soil class, cut and fill, access)
• Location (metro vs remote), delivery, and install labour
• Fit-out: insulation, power, windows, gutters to rainwater, solar-ready conduits

Tip: Ask for a single fixed-price proposal covering engineering certification, supply, delivery, installation, and slab to avoid gaps between trades.

Approvals: fast-tracking permits across Australia

How to Get Council Approval for Your Custom Shed in WA

Most 10×20 sheds in WA need a Building Permit. Your certifier or builder can package the application with engineering, site plan, elevations, and energy/structural documents.

• Confirm zoning and setbacks with your local council
• Provide engineered drawings and wind classification to AS/NZS 1170.2
• Include bushfire (BAL) assessment if mapped in a bushfire-prone area
• Check estate covenants for height/colour restrictions

For rural or regional shires, speak early with the building department—processing times and documentation expectations vary.

Other states at a glance

• QLD: Cyclone corridors need cyclone-rated sheds QLD with C-class design, wind-rated doors, and stronger hold-downs. Private certifiers often speed things up.
• NSW: Rural villages often allow exempt development under certain sizes and setbacks, but engineered plans still apply for larger sheds (rural sheds NSW).
• VIC: Bushfire overlays can affect cladding, ember seals, and glazing. Check with council or a private building surveyor.
• SA/NT/TAS: Local rules vary—confirm setbacks, easements, and drainage connections early.

council-approved sheds WA and custom Colorbond garages Perth are typically smoother when you use a supplier who handles site measure, engineering, certification, and submissions end-to-end.

Use-cases and fit-outs (ideas for every state)

• Single car or garage workshops Brisbane: roller door plus PA door, epoxy floor, 15A outlet
• 10×20 garden shed: racking, mower bay, daylighting panels, vermin flashing
• Small farm/acreage: quad or ride-on storage, lockable chemical cabinet, wash-down area
• Hobby studio/home gym: insulated roof/walls, vinyl plank over slab, split system allowance
• Add a matching awning or custom carports Melbourne for covered outdoor work

Case studies: recent Australian builds

Perth, WA — 3.0 x 6.0 m Colorbond gable shed

• Spec: N2 wind region, Monument walls, Shale Grey roof, anticon blanket
• Fit-out: 2.4 m roller door, PA door, gutter to rainwater tank
• Outcome: Lower summer heat with insulation; approved via certified application

Townsville, QLD — 3.5 x 6.0 m cyclone-rated workshop

• Spec: C2 wind rating, upgraded hold-downs, wind-rated roller door
• Fit-out: Louvre vents and whirlybird for airflow; Zincalume walls
• Outcome: Passed engineering inspection; excellent storm performance

Regional NSW — 3.0 x 7.0 m rural shed

• Spec: N3 wind, Zincalume cladding, skillion roof for solar-ready aspect
• Fit-out: Mezzanine over door, tool wall, 100 mm slab; vermin seals
• Outcome: Easy council approval in rural zone; great for farm machinery storage

DIY kit vs custom-built installation

5-Step Buying Guide for Custom Sheds in Australia

1. Confirm size and purpose: 3×6 m for car + storage, or 3.5×6 m for extra shelves.
2. Check your site: wind rating, bushfire map, setbacks, and access for trucks.
3. Choose materials: Colorbond for most homes; Zincalume for rural value; consider Colorbond Ultra near coast.
4. Lock in engineering: site-specific certification, wind-rated doors, slab spec.
5. Submit approvals and book install: aim for a single contract covering slab + shed to avoid gaps.

FAQs about 10 x 20 sheds in Australia

Is a 10 x 20 storage building big enough for a car?

Yes, a 3.0 x 6.0 m shed typically fits a small-to-medium car. Confirm roller door width/height and internal clearance.

Do I need a slab?

For a durable workshop or vehicle storage, a 100 mm reinforced concrete slab is standard. Some garden-only uses work with piers and a raised floor, but a slab adds longevity.

What about cyclones?

In cyclonic regions, specify C-class engineering, wind-rated roller doors, upgraded hold-downs, and tighter fastener schedules. Ask for cyclone-rated sheds QLD options.

Colorbond or Zincalume?

Colorbond is best for matched aesthetics and coastal homes (use Ultra near marine). Zincalume is great value for rural or farm settings.

How long does approval take?

Time varies by council and documentation quality. Using a supplier who handles certified plans and submissions usually speeds things up.

What ongoing maintenance is needed?

Rinse salt and dust, clean gutters, check door seals and fixings yearly. Follow the cladding manufacturer’s care guide.

Local standards, guidance, and useful links

• Australian Steel Institute — design and durability guidance: steel.org.au
• HIA industry updates (Outdoor Structures): hia.com.au
• Bureau of Meteorology (wind regions & tropical cyclone info): bom.gov.au
• CSIRO building science (condensation, materials): csiro.au
• Energy.gov.au (cool roofing, insulation): energy.gov.au

Recent reads: “2024 Australian Steel Market Outlook”, “2024 HIA Outdoor Structures and Home Improvement Report”. Always check the current AS/NZS standards and your local council requirements.

Why this guide outperforms generic advice

• Site-specific engineering aligned to AS/NZS, with WA and QLD notes
• Material selection tuned to climate (Perth heat, coastal corrosion, cyclone wind)
• Approvals tips for faster, cleaner council outcomes

Ready to design your 10×20 shed?

Whether you need a 10×20 garden shed, a compact workshop, or a single-bay garage, specify Colorbond or Zincalume correctly, insist on site-specific engineering, and plan approvals early. Ask for examples of council-approved sheds WA, steel sheds Perth, cyclone-rated sheds QLD, and industrial sheds Adelaide to match your region.