Loading steel structure components into a shipping container - overhead crane loading for export

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Steel Structure Shipping Container:
How Many Containers and What Goes in Them

Container count, bundle weights and the 11.8 m member limit — the numbers that decide how a steel building reaches your port.

04 Nov 2026Technical Guide

Buyers ask for the price first and the shipping plan a week later. By then the drawings are fixed, and the only question left is how many containers the steel takes and what must be split to fit.

What actually goes into a steel structure shipping container

A steel building leaves the factory as a kit of numbered components: primary frame, secondary steel, cladding, fasteners, accessories and anchor bolts. How each group is bundled decides the container count, not the tonnage on the invoice.

The primary frame is the awkward part. Welded H-sections do not stack flat and leave unfillable voids along the walls. Cladding is the opposite — light for its area, but it consumes volume. Secondary steel loads easiest.

Choosing a steel structure shipping container: size and payload limits

Most steel structure exports move in 40-foot boxes. The 40HC is the default because it pairs a 12.03 m internal length with 2.70 m of height — enough for a 250 mm sandwich panel on edge plus packing. The 20GP suits dense short items.

Two limits matter more than size. Payload is the weight the box may carry; road law at your destination port is usually tighter — commonly 18 to 22 tonnes for container, chassis and tractor, against a 26.5-tonne rating.

Standard dry container dimensions, tare and payload
Type	Internal L × W × H (m)	Capacity	Tare	Payload	Max gross
20GP	5.90 × 2.35 × 2.39	33.2 m³	2,200 kg	28,180 kg	30,480 kg
40GP	12.03 × 2.35 × 2.39	67.7 m³	3,750 kg	26,680 kg	30,480 kg
40HC	12.03 × 2.35 × 2.70	76.3 m³	3,900 kg	26,480 kg	30,480 kg
45HC	13.55 × 2.35 × 2.70	86.1 m³	4,800 kg	27,600 kg	32,500 kg

Typical ISO 668 values. Boxes vary by manufacturer, age and line — the CSC plate governs, and the road weight limit at the far end is usually the binding one.

How many steel structure shipping containers your building needs

Start from the weight, then apply packing reality. Take a 1,000 m² single-span workshop: 20 × 50 m, 8 m eaves, 0.6 mm sheet cladding, no crane. Frame steel is taken at an indicative 45 kg/m² — above the 35–45 kg/m² our quoting guide gives for a 15–18 m span workshop, since a 20 m span carries more.

Worked example — a 1,000 m² single-span workshop
System	Basis	Weight	Notes
Primary frame	20 × 50 m footprint, indicative 45 kg/m²	45.0 t	Bulk limits the count
Roof purlins	Z200 × 2.0 mm, 42 lines × 20 m = 840 m	4.85 t	Nests well
Wall girts	C200 × 2.0 mm, 4 lines × 140 m = 560 m	3.17 t	Nests well
Roof and wall sheet	0.6 mm, 2,220 m² at 4.71 kg/m²	10.46 t	Volume-limited
Fasteners and accessories	Boxed, grouped by connection type	1.50 t	Small volume
Total	Steel, sheet and accessories	64.98 t	≈ 2.4 by weight

Indicative only. Frame rate and sheet thickness are assumptions, not a quotation — final quantities come from the drawings and packing list. Purlin and girt masses are our own section data at 2.0 mm.

On weight alone that is 2.4 containers. In practice it ships in 3 to 4 × 40HC, because the frame is bulky and the cladding is volume-bound, not weight-bound. That gap is the art of the loading plan.

Packing rules that decide the steel structure shipping container count

Packing is specified before packing starts, the same for every shipment: heavy and long at the bottom, light and voluminous above, everything separated and identified.

How each component is packed for sea freight
Component	Packing method	What it does to the container count
Columns, rafters, crane beams	Steel loading frame or skid, timber separators at 2 m centres, corner protectors	Bulky — count set by space, not weight
Purlins and girts	Nested bundles of 10–30 pieces, strapping at 1.5 m or less, internal blocks against deformation	1–2 t per bundle; nests almost perfectly
Roof and wall sheet	Stacked flat with interleaving film, banded to timber skids	Light for its area, but volume-limited
Sandwich panel	Face-to-face stacks with edge and corner protection	Takes more volume per m² than single sheet
Bolts, clips, fixings	Boxed or in drums, grouped by connection type, foam filled	Small volume; kept clear of heavy loads
Doors, windows, gutters	Crated and labelled by type; large leaves reserve door space	Awkward shapes, packed to the plan

Standard export practice. Timber used as dunnage, pallets or crates must carry the ISPM 15 heat-treatment mark, and lashing is checked against the container securing manual.

Two details are worth checking on the packing list: every bundle should sit between 1 and 2 tonnes so one crane lift handles it, and timber should run under the members at 2 m centres or less, so a bundle cannot sag onto its own bolt holes.

Loading order and weight distribution inside a steel structure shipping container

Load in erection order: anchor bolts and base plates first, then columns, rafters, purlins and girts, cladding last — so opening containers in sequence at site hands your crew the next bay in order.

One number governs the main frame: 11.8 m, roughly the longest member that fits in a 40-foot container. Anything longer is designed with a bolted end-plate splice at the split, so the site crew bolts instead of welds — and that splice is drawn into the structure, not added on afterwards.

Purlin bundle weights from our own section data at 2.0 mm
Section	Mass per metre	Mass per 6 m length	Pieces per 1 t	Pieces at 26.48 t payload
Z150	4.99 kg/m	29.96 kg	33	883
Z180	5.46 kg/m	32.78 kg	30	807
Z200	5.78 kg/m	34.67 kg	28	763
C200	5.65 kg/m	33.91 kg	29	780
C250	6.75 kg/m	40.51 kg	24	653

Theoretical section mass, so bundle weights are predictable. The last column is payload-only: the real count is limited by bundle volume, the site crane and the 1–2 t per bundle rule above.

Frequently asked questions

Three to four 40HC for a single-span workshop with sheet cladding. Sandwich panels add roughly one more, since they take more volume per square metre. The exact count comes with the drawings.

About 11.8 m inside a 40-foot box. Longer rafters and columns are split with a bolted end-plate splice designed into the structure, so no site welding is needed.

A 20GP gives about 5.9 m of internal length and a 28,180 kg payload. It suits accessories, bolts, short purlin bundles and dense items — not a full frame.

VCI film on bare and galvanised surfaces, waterproof wrapping on bundles, desiccants in sheet bundles, timber dunnage underneath, and a tarpaulin cover for sea freight. Some flash rust on unpainted steel is normal.

A packing list for every container, listing each bundle and piece against the erection drawings, plus the commercial invoice, certificate of origin and mill test certificates. Loading photos are supplied for the record.

Send the drawings, get the container count with the price

Give us the building size, destination port and cladding type — we will come back with the frame tonnage, container mix, packing method and price, normally within 24 hours.

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