Padded materials for securing cargo in shipping

When loading a shipping container, gaps often remain between cargo items and between cargo and the container walls, and concentrated pressure may also occur between upper and lower layers of cargo. Preparing and correctly using dunnage materials before loading is a common method to prevent cargo from shifting or being damaged by pressure during transport. For an overview of securing methods, see What are the methods for securing containerized ocean cargo?; this article first discusses dunnage materials, and for the accompanying lashing tools, see Other tools and materials for securing ocean container cargo.

1. Common Materials and Uses of Container Dunnage

To protect cargo and keep it stable inside the container, dunnage such as partitions, uprights, dividers, and fences is often added between the cargo and the container walls during loading. Common dunnage materials include wooden boards, square timber strips or blocks, and plywood.

1. Wooden boards When different cargoes are loaded together, temporary wooden partitions may be placed between the cargoes to protect those with weaker packaging; when cargo is stacked more than two layers high, wooden boards may be inserted between the cargoes as padding to distribute the load of the upper layers.

2. Square wooden strips or blocks When the cargo does not fill the box completely, or when gaps have to be left between the cargo and the box walls, square wooden blocks can be used to wedge or brace tightly between the cargo and the box walls. Alternatively, vertical posts or barriers made of square wooden strips can be set up at the ends of the cargo to prevent movement or collapse.

3. Plywood Plywood, like wood boards, can disperse concentrated loads, making the pressure of the upper cargo evenly distributed. Plywood is slightly more expensive, but it is easy to operate and effective when making partitions and dividers.

2. Why container loading requires less dunnage than conventional cargo ships

The dunnage material used in container loading, when calculated by the material cost allocated per ton of cargo, is usually far lower than that of conventional cargo ships. There are three main reasons:

• Container floors are generally laid with wooden bottom boards, so most cargo does not need wooden pallets underneath;
• The container volume is much smaller than a cargo hold. Even when loading for separate ports or separate bills of lading, a large amount of separation material is not needed; different stowage methods can usually distinguish the consignments;
• Closed containers generally require no dunnage after being filled to capacity. Only when flat-rack or open-top containers are loaded with heavy cargo will the dunnage needed be significantly more than for closed containers.

Additionally, it should be noted that the dunnage materials used for containers differ from those used on ordinary cargo ships; they are generally single-use and not recycled, whereas dunnage on ordinary cargo ships can be reused after recovery. Therefore, accurately estimating the required quantity per bill of lading before loading can both ensure the quality of securing and avoid waste.

3. Precautions When Selecting Cushioning Materials

The material of the wood affects the strength of the cushioning. The following points are recommended when selecting:

(1) It is difficult to drive nails into knots; cut away any obstructing parts before use.

(2) Large knots reduce the strength of the material; cut off the parts containing large knots. The cut-off short pieces can be used as small support strips.

(3) Do not use cross-grained wood for components, as it has very low strength and is prone to splitting along the grain under load.

(4) A small amount of bark peeling on the wood does not affect its use and can be used normally as cushioning material.

Data Description: Dunnage and securing plans should be determined based on the nature of the cargo, container type, and shipping route; when exporting to certain countries, wooden dunnage may be subject to fumigation or fumigation-free quarantine requirements. Please confirm with your freight forwarder before booking.

📖 Further Reading: Methods for Securing Containerized Sea Freight — Overview of Common Securing Methods; Container Loading Specifications: Loading Sequence, Center of Gravity Control, and Securing/Lashing.

Need advice on loading and securing plans? Tell us the cargo type, packaging, dimensions, and number of boxes, and Bofeng Logistics can help you plan the dunnage and securing details.

Loading Consultation: 13075678958 | info@zhbfwl.com

Dunnage Materials Frequently Asked Questions (FAQ)

Q: Can dunnage materials be recycled and reused after use?

A: Wooden dunnage used in containers is generally treated as single-use and is not recycled or reused, which differs from reusable dunnage on bulk carriers. Therefore, it is important to calculate the exact quantity required for each shipment before loading. Remaining wood can be disposed of by the cargo owner or the container station in accordance with local regulations.

Q: What types of cargo usually require dunnage when loaded into containers?

A: Cargo involving mixed packages of different strengths, stacking more than two tiers high, failing to fill the container or leaving gaps against the container walls, as well as heavy cargo loaded in flat-rack or open-top containers, normally requires dunnage, partitions, or uprights to prevent damage from compression, shifting, and collapse.

Disclaimer: This article was compiled and written by the Bofeng Logistics team, with content verified in September 2026. The selection of dunnage materials and quarantine requirements may vary depending on destination country regulations, cargo type, and container type. Please refer to the booking confirmation and on-site instructions.