Strapping bricks, blocks and pavers: packs that hold from the yard to the site

Bricks, concrete blocks and paving units ask more of strapping than most palletised goods. A pack may leave a kiln or block press, stand in an open yard for weeks, be lifted several times by forklift, travel by road and arrive on a building site where someone cuts the strap by hand. Through all of that, the pack has to stay a pack.

This guide looks at what makes masonry loads different and how a buyer or packing engineer can specify strapping that suits them, as of June 2019.

Why masonry packs are demanding

• Density. A small pack carries a high mass, so the strap and joint see large forces when it is lifted, braked or set down hard.
• Edges and abrasion. Concrete and clay edges are hard and rough. Strap crossing them under tension can be scored or cut, especially at the top corners.
• Rigid units that can still move. The pack is stiff overall, but individual units can slide or work loose, particularly in the outer rows.
• Outdoor storage. Sun, rain and frost act on the strap and on any metal closures for as long as the pack stands in the yard.
• Manual unpacking. On site the strap may be cut by people without packing training.

Choosing the strap

PAC Strapping Products’ FAQ summarises the main differences between strap materials in terms that apply directly to masonry:

Strap	Characteristics described by PAC	What it means for masonry packs
Steel	Very low elongation; typically used on rigid loads; recommended for heavy loads with sharp edges; heavy to handle; spring-back risk when cut under tension	Resists edge damage well; unpacking needs a safe cutting method
Polyester (PET)	Used where higher break strength and retained tension are needed; recovers most of its stretch so it stays tight if the load settles	Holds tension as packs settle in storage; edges need protection
Polypropylene	Economical and lightweight, with higher elongation; suited to compressible or expanding loads	Rarely a natural fit for dense, rigid masonry packs

The choice is not only technical. PAC singles out spring-back as a hazard when steel strap is cut under tension, which matters if packs are opened by site labour. Any tensioned strap should still be cut with care, and polyester strap needs attention at the edges.

Joints, closures and tools

Plants that strap masonry in high volumes may use strapping machines, which join plastic strap themselves. Closures still matter in three places: manual stations for odd packs, repairs in the yard when a strap is damaged, and steel-strapped packs.

For steel strap, Signode’s seal guidance explains the difference between notch joints, which form a mechanical interlock, and crimp joints, which rely on friction and which Signode associates with uses such as carloading, where loads see severe impact. For polyester strap closed by hand, a crimped clip must match the strap width, thickness and tool.

Outdoor storage affects metal closures too. Consider how long a closure will be exposed to rain and humidity before the pack is opened, and choose the finish with that period in mind.

Strapping holds the pack; it does not secure the load

Pack strapping forms a unit. Keeping that unit in place on a lorry bed or in a container is a separate job, and masonry tempts people to skip it because the packs are heavy and seem to stay where they are put. The CTU Code gives a friction factor of 0.7 for concrete with a rough surface against sawn wood, yet chapter 5 warns that the mass of the cargo, even with a high friction coefficient, does not sufficiently secure it, because vibration can move it. Annex 7 treats compacting by strapping as an auxiliary measure to be combined with blocking, lashing or friction securing.

In practice, agree with the haulier how packs will be blocked or lashed, and do not count a tight pack strap as a lashing. If packs travel in containers, the stow and the securing method belong in the packing instruction alongside the strap pattern.

Protect the edges

Corner boards or edge protectors at the top edges reduce the pressure of the strap on hard corners and spread its load. Check the strap path as well: a strap that crosses a protruding unit or a pallet edge is exposed at that point, whatever protection sits at the corners. The sharp edges and abrasion guide lists the contact information worth including in an enquiry.

A pack specification worth writing down

• Unit dimensions and the pack pattern, including the number of layers.
• Pack mass, taken from your product data.
• Pallet type, or the arrangement used for palletless packs.
• Expected storage period and exposure.
• Handling equipment in the yard and at delivery.
• Strap reference, nominal width and the strap pattern: how many straps, in which directions and where.
• Joint method and, where used, the closure and tool.
• Edge protection and its position.
• A safe opening instruction for site staff.

Review the specification with the packing team at each plant. Drift in strap count or position between shifts or plants can explain why the same pack design holds in one place and fails in another.

If your packs use PET strap closed by hand with sheet metal clips, or steel strap with steel strapping seals, send the strap reference, tool and pack details through the enquiry page so the closure can be discussed against your own pack.