Plastics Logistics : Wood Blocking and Bracing for Container Load Securement

Wood blocking and bracing (also known as dunnage) is a method of using wooden components, such as boards, beams, cleats, and wedges to secure pallets and cargo inside shipping containers. These wooden elements are strategically nailed, screwed, or bolted to the container floor or walls to prevent load shifting during transport.

Common applications:

Load restraint systems:

• Flooring Cleats: wooden boards (typically 2×4 or 4×4) nailed directly to the container's wooden floor to create barriers that prevent pallet movement
• Cross-Bracing: diagonal wooden supports installed between pallets and container walls to distribute forces during transit
• Load Bars: horizontal wooden beams spanning the width of the container to separate cargo sections or provide additional stability

Gap Filling:

• Void fillers: wooden blocks installed in empty spaces between pallets and container walls
• Chocking: wedge-shaped pieces nailed at the base of round objects or wheeled equipment
• Cribbing: stacked wooden blocks used to support heavy machinery or irregularly shaped items

Real-life examples:

Heavy machinery transport:

A manufacturer shipping a 12,000-pound plastic injection molding machine overseas uses:

• 4×4 wooden skids as a base
• 2×6 boards nailed to the container floor surrounding the skid base
• Diagonal cross-bracing from the upper portions of the machine to the container walls
• Each board secured with 6-inch hardened nails driven into the container's wooden floor

This system successfully prevented any movement during a transoceanic journey, including through a storm with 30-foot waves.

Mixed pallet loads:

A chemical company shipping multiple pallets of plastic additives in drums uses:

• 2×4 lumber nailed to create a perimeter around groups of four pallets
• 1×4 boards nailed across the front of the first row of pallets
• Wooden braces at 45-degree angles from the floor to the sidewalls
• Approximately 40 nails used throughout the container

This system kept their load secured despite multiple intermodal transfers between truck, rail, and ship.

Fragile product protection:

A manufacturer of acrylic displays implements:

• Custom-cut wooden frames nailed to surround each pallet
• Horizontal wooden slats between pallet layers
• Corner blocks to maintain spacing and prevent contact between products
• Over 100 nails used in a systematic pattern throughout the container

This comprehensive bracing reduced damage claims by 87% compared to previous methods.

Considerations and best practices:

Container floor construction: 

Most containers have 1-1/8" wooden floors suitable for nailing, but check specifications before loading

• Nail Selection: Use hardened spiral or ring-shank nails (typically 3-4" for most applications)
• Nail patterns: space nails at least 2" apart to prevent floor splintering
• Nail angle: drive nails at slight angles for better holding power
• Removal requirements: consider ease of dismantling at destination
• Sustainability: some destinations require heat-treated wood to prevent pest transfer

Hardened spiral or ring-shank nails: specialty nails with twisted or ringed patterns on the shaft that provide superior grip. They resist pulling out and are ideal for securing materials that need extra holding power

When properly implemented, wood blocking and bracing is one of the most reliable and cost-effective methods for securing container loads, particularly for heavy or high-value plastic industry products.