Every Shed Homes design uses portal frame steel construction - the same structural system used in commercial and industrial buildings, scaled for residential living. It’s the reason our homes can achieve wide open spans, resist cyclone-rated wind loads, and go from slab to lockup in weeks rather than months.
What Is a Portal Frame?
A portal frame is a rigid structural frame made from steel columns and rafters connected with moment-resistant joints (typically bolted knee connections). The frame transfers roof and wind loads down through the columns to the footings - without needing internal load-bearing walls.
This is fundamentally different from conventional timber frame construction, where internal walls carry load and the design is constrained by timber span limitations.
Portal Frame vs Timber Frame: The Comparison
Clear Spans
Steel portal frame: Achieves clear spans of 12m, 15m, 18m or more without any internal support. Your floor plan has zero structural constraints.
Timber frame: Typically limited to 4–6m spans between load-bearing walls. Internal walls must be positioned to carry roof loads, which dictates your floor plan.
Termite Resistance
Steel: Termites cannot eat steel. Zero risk, zero ongoing treatment costs.
Timber: Requires ongoing termite management - chemical barriers, physical barriers, or regular inspections. In Queensland and northern NSW, termite damage is the single biggest structural risk to timber homes.
Fire Performance
Steel: Non-combustible. Steel frame with COLORBOND® cladding meets BAL-29 bushfire ratings without modification. Higher BAL ratings achievable with appropriate design.
Timber: Combustible. Requires significant additional protection in bushfire zones - fire-rated cladding, ember guards, and restricted glazing.
Construction Speed
Steel portal frame: Frame and roof typically erected in 1–2 weeks. Lockup (frame, roof, walls, doors) in 2–4 weeks.
Timber frame: Frame, roof truss, and lockup typically takes 6–10 weeks. More trades, more coordination, more weather delays.
Precision
Steel: Every component is factory-made to millimetre tolerances. Pre-punched, pre-drilled, and labelled. Minimal on-site cutting or modification.
Timber: Cut on site. Quality depends heavily on the carpenter’s skill. Timber moves, warps, and shrinks as it dries - especially in Australian conditions.
Engineering You Can Trust
Every Shed Homes design is engineered by a registered structural engineer for your specific site. The engineering package covers:
- Wind load calculations for your terrain category and wind region
- Footing design matched to your soil classification
- Frame connection details - every bolt, bracket, and brace specified
- Bracing layout for lateral stability
- Snow loads (for alpine regions)
This isn’t generic engineering - it’s calculated for your exact location, dimensions, and design choices. The drawings are what your council needs for approval and what your builder or trades need during construction.
The 3D Advantage
Shed Homes takes engineering a step further. Once your design is finalised and engineered, you receive access to an interactive 3D model of your exact home. Every component is mapped - columns, rafters, purlins, girts, bracing, flashings, right down to individual tek screws.
Search by part number from the bill of materials and the model highlights exactly where that piece fits. For owner builders, this is invaluable - you always know what goes where and how many you need.
Visit our owner builder page to see screenshots of this 3D component mapping in action.
Who Chooses Portal Frame?
Portal frame shed homes are ideal for:
- Acreage owners - rural and semi-rural blocks where space allows large footprints
- Owner builders - the pre-fabricated system is designed for non-trade assembly
- Families wanting open-plan living - no internal load-bearing walls means total design freedom
- Bushfire zones - non-combustible steel meets higher BAL ratings
- Cyclone regions - engineered for C1–C4 wind categories
- Tree changers and retirees - faster build time means you’re in your home sooner
Ready to explore? View our 7 standard models or customise your own design in 3D.