General Purpose Shipping Containers

The box behind the jargon

"General purpose" — GP on a shipping manifest — is the ordinary dry-cargo container. Corrugated weathering-steel walls and roof, a welded frame with a twist-lock casting at each corner, a hardwood or marine-ply floor laid over steel cross-members, and two doors at one end that seal against rubber gaskets when the locking bars are thrown. It has no refrigeration and no side access. It was designed to be stacked nine high on a deck in an ocean swell, so a cane paddock or a backyard holds no surprises for it.

Here it comes in 10ft, 20ft and 40ft, all 2.59m tall outside. For an extra 300mm of headroom see the high cube. For fuel, oils or farm chemical, the dangerous goods unit is a separate product — a GP box is not a compliant substitute.

Matching the grade to the cargo

Start with what is going inside, then pick the grade. Furniture, paperwork and anything that minds damp wants a cargo-worthy used unit at least — it is checked wind and watertight before it travels, and it will show its years on the paintwork. Anything staying for a long time within sight of the sea at Bargara, Burnett Heads, Elliott Heads or Woodgate is worth a new single-trip unit, because salt finds scratches and a fresh coat buys years. As-is units are cheaper and are not sold watertight — fine for scrap steel, star pickets or a windbreak, wrong for a lounge suite.

Inland at Gin Gin, Mount Perry or Gayndah, a sound cargo-worthy unit weathers slowly and is the sensible buy for nearly everything.

Lengths, by what they hold

A 10ft holds a garden shed's worth — mower, outboards, fuel cans kept apart. It costs more than a 20ft because it is cut down and rebuilt, so buy one only when length really is the limit.

A 20ft holds a house during a renovation, or a trade business's stock. Tilt-tray delivery, which most town driveways can take.

A 40ft holds the farm and business volumes — cartons, bins, pallets, machinery spares. Sidelifter delivery, about 30 metres of room and firm standing.

Where it sits decides how long it lasts

Put a block, sleeper or paver under each corner casting so the floor is off the dirt and air can pass underneath. Choose the highest firm ground you have: a container keeps rain out from above, but water rising around it reaches the door seals and gets in, and an empty unit can float. Turn the doors away from the south-easterly if the block allows, keep the hinges and locking cams greased, and treat rust spots the first season you see them.

Sealed steel in coastal humidity also sweats overnight. If the cargo minds moisture — upholstery, cardboard, hand tools — add vents or moisture absorbers. Tell us what is going in and we will suggest which.

Buy it, or hire it for the job

Every GP unit can be bought outright, and 20ft units can be hired weekly for work with a finish line — a renovation, a harvest, a move between houses. Cartage is quoted with the container because it depends on the address and the access, and you get one figure for both. Sales and hire compares the two; deliveries covers what the truck needs.