20ft Hard Open Top Container | Removable Steel Roof | ACE Container & Parts

Created on 09.24

What It Is

A 20ft hard open top container is a standard 20ft general purpose container with one change: the roof is removable. Instead of a welded steel roof, two steel panels sit on the top rails, clamped down onto a gasket. Release the clamps, crane the panels off, load from above, replace the panels, and the box is watertight again.

Everything else is standard. ISO 668 external dimensions. ISO 1161 corner castings, so it stacks and is handled like any other 20ft box. Standard end doors for access at floor level, plywood flooring on steel cross members, and Corten steel structure.

It is not a soft top — no tarpaulin to tension. It is not a flat rack — the walls and doors are still there, so cargo stays contained. And it is not a cut-down dry box: the removable roof is designed in from the start, with the top structure sized for the opening.

Why Load From Above

The end door of a 20ft container is 2,280 mm high. Anything taller than that will not go in through the door — no amount of ramping, tilting or forcing changes that.

Loading from above solves it:

Cargo taller than the door opening

Cargo a crane has to place, not a forklift push

Faster on oversized items

Full enclosure afterwards

Normal stacking

Hard Open Top vs Soft Open Top vs Flat Rack

All three are bought when cargo will not fit through the door. They are not interchangeable.

	20ft Hard Open Top	20ft Soft Open Top	20ft Flat Rack
Roof	Removable steel panels	Tarpaulin on a removable bow frame	None
Weather protection	Full, permanent	Good, but the tarp needs handling	None
Security	Steel roof, doors lockable	Tarpaulin is cuttable	No walls at all
Handling the cover	Crane each panel on and off	2–3 people to fit and tension the tarp	—
Container reuse	Re-seals like a dry box	Tarp ages, bows bend	—
Best for	Tall or heavy cargo, kept in the box for a long period, repeated reuse	Occasional overhead loads, cost-sensitive	Out-of-gauge cargo, sides open required
Ships as	Standard 20ft box	Standard 20ft box	Often needs special stowage

Simple rule: if the cargo stays inside the container for the voyage and you want it protected and secure, choose hard open top. If a tarpaulin is good enough and budget is tight, choose soft top. If the cargo will not fit inside any container, choose flat rack.

Specifications

Parameter	Value
External length	6,058 mm
External width	2,438 mm
External height	2,591 mm
Internal length	5,898 mm
Internal width	2,352 mm
Internal height	2,393 mm
Door opening (W × H)	2,340 × 2,280 mm
Internal volume	≈ 32.5 m³
Tare weight	≈ 2,600 kg
Maximum gross weight	30,480 kg
Maximum payload	≈ 27,800 kg
Roof	2 removable steel panels, gasketed, clamped to the top rail; crane-handled individually
Roof panel weight	≈ 300 – 400 kg per panel (confirmed on the GA drawing)
Structure	Corten A / SPA-H side and end walls, corrugated
Floor	28 mm marine plywood on C-section cross members, fork pockets at 1,025 mm
Coating	Epoxy zinc-rich primer / intermediate / polyurethane topcoat; marine-grade upgrade available
Certification	ISO 668 · ISO 1161 · ISO 1496-1 · CSC plate

The Engineering Most Buyers Never Ask About

A removable roof is a structural interruption, and where the interruption sits is what separates a properly built hard open top from a dry box with the roof cut off.

In a standard dry container, the roof is working. It ties the two side walls together along the top, shares the racking load that tries to lozenge the box when it is lifted or shipped at an angle, and helps the walls resist cargo pressure from inside. Remove it and that job falls on the perimeter top rail alone. So the top rail has to be heavier, the corner connections reinforced, and the clamp spacing close enough that the panels transfer load to the rail instead of flexing between clamps. A rail sized for a static roof will not do the work of a rail that is part of the primary structure.

The panel is a lifting item in its own right. Every time it is removed, the panel is craned, set down, picked up and craned back. If it is not stiff enough — or if there is no defined lifting point — the panel bends, and a bent panel will not seat on its gasket again. Ask for the per-panel weight and how the panel is lifted.

The joint is the leak path. A welded roof leaks at the weld; a removable roof leaks at the gasket, the clamp line and wherever water sits. Ask where the panel joint sits relative to the top rail, whether the panels are cambered so water runs off rather than pools, and what the gasket material is.

Ask a supplier for the top rail section, the roof panel weight, the clamp spacing and the gasket detail. A supplier who has these answers is building a hard open top container. A supplier who does not has cut the roof off a dry box and bolted two plates back on.

Sealing, Hardware and Security

Multi-point locking bars on the end doors, four cam keepers per leaf

EPDM gaskets on all door leaves, plus a gasket and weather seal around the roof opening

Clamps recessed so they are not caught or sheared in handling

Roof access hatch and personnel hatch options for occupied or serviceable units

Water test on request; drainage checked at the panel joint, which is where standing water shows up first

Customisation

Roof

Floor

Doors

Insulation and lining

Electrical fit-out

Internals

Coating

Where They Are Used

Tall and heavy machinery, plant skids and fabricated assemblies

Transformers, generators and switchgear

Precast concrete, stone and marble slabs loaded flat

Boats, small craft and out-of-gauge plant

Project cargo that must stay boxed and sealed for a long sea voyage

Why ACE

ACE Container & Parts has exported containers for 16 years, working with 50+ partner factories and serving more than 2,000 customers in 130+ countries. We quote the box and the roof arrangement together — on a hard open top they are one design decision — and we will tell you plainly if a soft top or flat rack suits your cargo better.

ACE Container and Parts Co., Limited is a professional supplier of shipping containers and container parts. We were founded in 2011 and located in Tianjin, China. There is Xingang Port, the largest port in North of China. About 60km far from Beijing International Airport.

We are the No.1 shipping container supplier. We can provide One-Stop shipping container solution for customers. We have obtained ISO9001 and SGS certificate. We can provide shipping containers with CCS, BV, LR, DNVGL Certificate.