Double Wall Cardboard Boxes

Double walled corrugated boxes, supplied flat in trade packs for UK sellers, warehouses and trade counters. Also sold as double-walled cardboard boxes, double wall cartons or 5-ply boxes — the same product under different names. These are the boxes for weight, fragility and stacking: the ones you reach for when single wall isn't enough.

What double wall means

Double wall is 5-ply corrugated board: liner, flute, liner, flute, liner. Two separate corrugated layers, usually running at different flute heights so that one absorbs impact while the other carries compression.

That second flute layer is the whole point. It roughly doubles the resistance to crushing, punctures and stacking load compared with 3-ply single wall, at the cost of more weight and more board. Typical working range is 25–40kg, depending on the box, the grade and how the weight sits inside it.

When to step up from single wall. The deciding factor isn't weight, it's consequence. Three situations call for double wall regardless of how heavy the contents are:

• Fragility. Glassware, ceramics, electronics, anything with a breakage history. A 4kg box of mugs needs double wall; a 12kg box of paperbacks does not.
• Stacking. Anything held in a warehouse more than three high, or going through a courier cage where your parcel sits at the bottom of the pile. Double walled packing boxes hold their shape under load where single wall deforms.
• Value. If a damaged item costs you the sale, the refund and the return shipping, the extra board is cheap insurance.

For everything lighter and more forgiving, single wall cardboard boxes are the correct specification and cost less to buy and to ship.

Specifications and terminology

Corrugated board is described in shorthand that isn't obvious unless you buy it weekly. The terms that matter when comparing suppliers:

Ply — the number of paper layers. A double walled box is 5-ply: three liners, two flutes. Single wall is 3-ply. More ply means more compression resistance and more weight.

Flute profile — the height and pitch of the corrugation. Taller flutes cushion better; shorter flutes stack better and print more cleanly. Double wall combines two profiles so the board does both jobs at once, which is why it outperforms a single thick layer.

Liner — the flat sheets. Kraft liner is brown, stronger and higher in virgin fibre; test liner carries more recycled content. Kraft takes labels and print more crisply.

Edge Crush Test (ECT) — force the board withstands on its edge before crushing. This is the number that predicts stacking performance, and the most useful single figure when two boxes look identical on paper.

Bursting strength — puncture resistance. Matters for dense goods and sharp corners.

Flat-packed — supplied folded, assembled with standard tape, no tooling. A pallet stores in a fraction of the space of made-up boxes.

For double wall specifically, ECT is the figure to compare. Ply tells you the construction; ECT tells you what it will actually withstand.

Choosing a size

Sizes, codes and pack quantities are in the table below. Three things decide which you need.

Measure the product packed, then add 20–30mm per side. With fragile goods you may want more clearance for void fill — but fill is there to stop movement, not to fill a box you shouldn't have bought.

Match the shape. A cube and an oblong of equal capacity behave very differently around a stack of plates or a boxed appliance. Look at the proportions, not just the volume.

Size down before you size up. Couriers charge on the greater of actual or volumetric weight, and double wall is already heavier than single wall — so an oversized box costs you twice. Our cardboard boxes page works that calculation through properly.

Common jobs, and what usually works

Glassware, ceramics and homeware. The classic double wall case. Pair it with proper internal protection — the board stops crushing, but it won't stop items knocking together.

Electronics and appliances. Double wall for anything with a screen, a motor or a board inside. Snug fit matters as much as grade.

Bulk books and print. Single wall handles the weight, but a full carton of hardbacks in a courier cage is a stacking problem, not a weight problem. Use double walled boxes for anything shipped in quantity.

Machinery parts and automotive. Weight and sharp edges together — this is where bursting strength earns its place alongside ECT.

Warehouse and long-term storage. If boxes sit stacked for months, double-walled cardboard holds its shape where single wall deforms at the bottom of the pile.

Higher-value retail goods. Where a damage claim costs more than the packaging difference across an entire pallet, the calculation makes itself.

Removals and storage. Removal firms and self-storage operators buy double wall for the same reason: a box that's lifted, stacked, driven and stacked again gets handled far more than a box that goes straight to a courier. Double wall survives the second and third handling; single wall often doesn't.

If you're moving house yourself rather than moving other people's things for a living, be aware these are sold in trade packs with a £75 minimum — worth checking the quantity suits before you order.

Buying by the pack

Supplied flat-packed in trade packs, with price breaks as pack quantities increase. Prices exclude VAT.

The board is made by our own manufacturing group, so the box is produced in-house rather than bought in and resold. Behind it sits over 100,000 square feet of warehousing, which is the part that matters on a product like this — the size you standardise on this month is the size that's still on the shelf when you reorder, rather than one you wait on a production run for.

Double walled packing boxes cost more per unit than single wall, so the temptation is to use them sparingly or to use them everywhere. Both are mistakes. Split your range by fragility rather than by size — one or two double wall formats for the products that genuinely need them, single wall for the rest. That usually beats a uniform choice in either direction.

Practical detail

Assembled with standard tape, no tooling required. The kraft outer takes labels, direct print and barcodes cleanly. Fully recyclable, and compatible with Royal Mail, Parcelforce, Evri, DPD, Yodel, UPS and DHL.

Not sure where the line between single and double wall falls for your product mix? Send us your dimensions, weights and any damage history and we'll work through it with you.

Delivery and returns

Next-day dispatch on UK mainland orders, with a £75 minimum order. Full terms on our delivery and returns pages.