What Is a Portal Frame Storage Shed?

A portal frame shed uses rigid steel columns and pitched rafters to create a self-supporting structure with no internal posts. The result is a fully clear internal span, where every square metre of floor space is usable.

Trusteel Fabrications builds these frames using Rectangular Hollow Section (RHS) steel as standard, moving to universal beams or Open Web Trusses for the widest custom storage sheds. Most shed suppliers use C-section (or C-purlin) framing instead. C-section is lighter, cheaper to produce, and adequate for small or low-load structures. RHS is heavier, more rigid, and significantly more durable under sustained load or in high-wind environments.

The difference matters most in sheds wider than 9m, in rural or coastal locations with elevated wind loads, and in any application where the shed needs to perform reliably for 20 to 30 years.

Sizes and Specifications

Trusteel portal frame storage sheds are available up to 18m wide. That covers the majority of residential, rural, and commercial storage applications without requiring internal support columns.

Common configurations include widths of 6m, 9m, 12m, 15m, and 18m (approximately 20ft, 30ft, 40ft, 50ft, and 60ft). Wall heights typically range from 3m to 6m, depending on intended use. Bay spacing and roof pitch are configured to suit your site and load requirements.

Custom dimensions are available beyond standard configurations. For storage sheds wider than 18m, Trusteel specifies universal beams or Open Web Trusses instead of RHS, since both carry load across a longer unsupported span. If your storage requirement falls outside these parameters, Trusteel can design to your specific measurements.

What Can a Storage Shed Be Used For?

Portal frame sheds suit a wide range of practical storage applications across residential, rural, and commercial properties.

Common uses include:

  • Machinery and equipment storage: tractors, implements, and large outdoor equipment that require covered, clear-span access
  • Commercial goods storage: stock, materials, and palletised product for small-to-medium business operations
  • Rural and farm storage: hay, grain, and agricultural inputs requiring weather-protected outdoor storage
  • Vehicle storage: cars, trailers, boats, and recreational vehicles requiring a durable covered space
  • Tool and workshop storage: a backyard shed configured for tradesperson or hobbyist use, with room for benches and equipment
  • Small-scale industrial: light manufacturing, fabrication, or processing operations needing a clear-span workspace

Portal Frame vs. Other Storage Shed Types

Choosing the right shed type depends on span width, intended use, site permanence, and budget. The three main alternatives to a portal frame steel shed are container sheds, flat-pack kit sheds, and C-section frame sheds.

Structural difference

  • Portal frame (RHS, UB, or OWT): rigid welded frame, clear internal span, engineered for permanent installation and sustained load
  • Container shed: repurposed shipping container, fixed dimensions (typically 6m or 12m), no span flexibility, no permit required in most cases
  • Flat-pack kit shed: C-section or light gauge steel, bolt-together assembly, suitable for light-duty outdoor storage and backyard use
  • C-section frame shed: similar portal configuration to RHS but using lighter, open-section steel; cheaper to produce but less durable under load

Cost difference

  • Portal frame (RHS): higher upfront cost than all alternatives; appropriate where longevity, span, and structural integrity justify the investment
  • Container shed: lower cost for short-term or relocatable storage; limited by fixed dimensions and no custom sizing
  • Flat-pack kit shed: lowest cost; appropriate for small residential or tool storage where loads are light and spans are short
  • C-section frame shed: mid-range cost; suitable for light commercial or rural storage where budget is a constraint and long-term durability is less critical

When each is the right choice

  • Portal frame (RHS): spans above 9m, permanent installation, heavy or sustained loads, permit-compliant construction, 20+ year asset life
  • Container shed: temporary or relocatable storage, short-term need, no site works required
  • Flat-pack kit shed: small backyard or residential outdoor storage, light-duty use, owner-assembled
  • C-section frame shed: budget-constrained rural or light commercial applications where a shorter service life is acceptable

To get an indicative cost based on your span and intended use, use our free Shed Designer to work through dimensions and configuration. 

Storage Shed Permits in Victoria

Under the Building Regulations 2018 (Regulation 87), a Class 10a structure (which includes storage sheds) may be exempt from a building permit if it meets specific area, height, and setback thresholds. In practice, most permanent sheds above 10 square metres, or those near boundaries, will require a permit.

Additional overlays apply in many Victorian zones. Rural and farming zones may have specific requirements. Bushfire-prone areas require compliance with Bushfire Attack Level (BAL) ratings. Council requirements vary, and what applies in one municipality may differ in another.

Trusteel is registered with the Victorian Building Authority (VBA) as a building practitioner. This means Trusteel manages the permit application as part of the construction process. You do not need to engage a separate registered builder or navigate the permit process independently.

The Trusteel Build Process

Every Trusteel storage shed follows a five-stage process, handled entirely in-house.

Stage 1: Site evaluation. Trusteel assesses your site, access, soil conditions, and any relevant zoning overlays before quoting.

Stage 2: Quotation. A fixed-price quote is provided based on your specifications, site conditions, and any permit requirements identified at stage one.

Stage 3: Custom design. Engineering drawings are prepared to your exact dimensions, including structural calculations required for permit submission.

Stage 4: Manufacture and fabrication. Your shed is fabricated at Trusteel’s Melbourne facility using RHS structural steel, or universal beams and Open Web Trusses for storage sheds wider than the standard 18m range. All components are produced in-house.

Stage 5: Installation. Trusteel’s crew installs the structure on your site. Concreting is included where required, so you do not need to coordinate a separate concretor.

Contact Trusteel to get a custom quote for your storage shed.

Frequently Asked Questions

How much does a portal frame storage shed cost in Victoria?

Portal frame storage sheds typically start from $15,000 to $20,000 for smaller configurations, depending on size, wall height, and specification. Larger commercial or rural sheds will cost more. Site-specific factors such as concreting, permit fees, and access conditions also affect the final price. The most reliable way to get an accurate figure is to request a site-specific quote.

Do I need a council permit for a storage shed on my property?

Most permanent storage sheds above 10 square metres require a building permit in Victoria under the Building Regulations 2018. Exemption thresholds apply to smaller structures, but setback distances, wall heights, and site overlays can affect whether an exemption applies. Requirements vary between councils. Checking with your local council or engaging a registered builder like Trusteel to assess your specific situation is the most reliable approach.

What is the difference between an RHS, UB, or OWT portal frame shed and a C-section shed?

RHS, universal beams, and Open Web Trusses are all structural steel, significantly stronger than the open-profile, lighter-gauge C-section used by most volume shed suppliers to reduce cost. Trusteel uses RHS as standard up to 18m wide and moves to universal beams or Open Web Trusses beyond that. All three are heavier, more rigid, and more durable under sustained load than C-section, making them the appropriate choice for long-span, heavy-use, or permanent storage applications.

What sizes are available for steel storage sheds?

Trusteel builds portal frame storage sheds from 6m wide up to 18m wide using RHS as standard. Wall heights typically range from 3m to 6m. Bay spacing and roof pitch are configured to your requirements. Custom dimensions are available outside these standard ranges, with universal beams or Open Web Trusses specified for sheds wider than 18m, and Trusteel can design to your exact site and usage specifications.

Does Trusteel manage the permit application, or do I need to organise that separately?

Trusteel manages the permit application as part of the construction process. Because Trusteel is a registered building practitioner with the Victorian Building Authority (VBA), no separate registered builder is required. You do not need to submit permit documents independently or coordinate with council on your own. Permit management is included in the Trusteel build process from design through to approval.