The choice between panel-built and board-built packaging is usually made on price, which is a shame, because the two behave differently in ways that matter more than the price gap.
The core argument for panels
Solid boards shrink and swell across their width as moisture content changes. Over a long voyage, boards that fitted tightly at the factory open into gaps, and joints that were sound become loose. Panel products — plywood, OSB — do not do this: their cross-laminated construction means no significant shrinkage and no consequent opening of joints.
That single property is why returnable and multi-trip packaging is usually panel-built. A solid-board crate degrades a little on every trip as its joints work loose; a plywood case does not, which is also why knock-down crate systems are made from plywood rather than boards.
Plywood grades — the distinction that matters
Not all plywood is suitable for export packaging. The German standard DIN 68705 distinguishes two bonding classes, and the difference is stark:
- IF — resistant only in enclosed spaces at generally low humidity. Not weather-resistant.
- AW — resistant even under severe moisture exposure, and moderately weather-resistant.
If your packaging will sit on a quay, cross the tropics, or be stored outdoors at the destination, IF-bonded plywood will delaminate. This is a specification line worth writing down rather than assuming, because the two look identical when new.
Typical veneer boards run 4–15 mm in 3, 5 or 7 plies. Wood core boards, with a conifer batten core, run roughly 15–32 mm.
For OSB the equivalent grading is EN 300: OSB/1 general purpose dry, OSB/2 load-bearing dry, OSB/3 load-bearing in wet conditions, OSB/4 high load capacity in wet conditions. For export packaging exposed to moisture, OSB/3 or OSB/4 are the relevant grades — OSB/1 and /2 are interior products.
Chipboard: don't
This deserves its own heading because it still turns up in cheap packaging. Chipboard is difficult to nail, its cut edges splinter, and it is generally unsuitable for packaging applications.
More seriously, chipboard has an elevated acetic acid content, which creates a corrosion risk. It must never be used inside climate-controlled packaging — a sealed barrier package containing chipboard is actively corroding its own contents. If you are packing metal parts and someone offers a chipboard-lined case, that is a reason to walk away.
Fibreboard is a different material and has its uses at 2–6 mm; the rule there is simply that the smooth, water-repellent face should always face outwards.
The ISPM 15 trap
This is the single most expensive misunderstanding in this area, so it is worth being precise.
Plywood, OSB, particle board and veneer are exempt from ISPM 15 — manufacturing them with glue, heat and pressure already renders them free of pests, so no treatment and no mark are needed.
But the exemption applies only to packaging made wholly of processed wood. A plywood case mounted on a solid-timber skid base, or built with solid cleats and corner battens, is not exempt. Those solid components fall squarely under the standard and must be heat treated and marked.
Because such a case looks like a plywood box and gets described as one, exporters are caught out regularly. If your packaging mixes plywood panels with sawn timber — and most plywood cases do, somewhere — treat it as in scope.
A related nicety: under ISPM 15's repair provisions, plywood replacement panels may be used to repair treated packaging without themselves needing treatment, because they are exempt processed wood. That is genuinely useful for maintaining a returnable fleet.
Joints and fasteners
Construction quality often matters more than material choice. A few facts that decide how long packaging lasts:
- Board-to-board joint strength, best to worst: tongue-and-groove and dovetail, then lap, then butt. A butt joint has essentially no effect on strength — it holds the boards in position and nothing more.
- Nails: ribbed and screw nails have far greater extraction resistance than plain wire nails. The nail head should always be in the thinner component. Blunt-ended nails split wood less than sharp ones. Clinching the protruding end increases holding power substantially.
- Screws need a pilot hole about half the screw diameter and about 70% of the shaft length — and must be screwed in, never hammered.
- Bolts: head outside the box and countersunk, secured inside with self-locking nuts and washers, with no more than 1 mm of play in the hole.
Choosing between them
Solid boards suit one-way packaging, heavy and rugged items, crates where ventilation is wanted, and situations where field repair with locally available timber is likely. They are usually cheaper per unit and are entirely appropriate for a great deal of transport.
Plywood suits multi-trip and returnable systems, long sea voyages where joint integrity matters, high-value or sensitive contents needing a closed and dust-tight enclosure, and knock-down designs that must be assembled and dismantled repeatedly.
The honest summary is that most export packaging is a hybrid — plywood panels on a solid timber frame and skid base — which captures the dimensional stability of panels and the strength and repairability of solid wood. Just remember what that hybrid means for your ISPM 15 obligations.
