Single wall vs double wall: when the upgrade pays
4 min read
Most parcels are fine in single wall. Here's when double wall — heavy loads, high stacks, long storage, fragile contents — is actually worth the extra cost.
What the difference actually is
Single-wall board is one fluted layer glued between two flat liners. Double wall adds a second fluted layer and a third liner, making the board thicker, stiffer, and much harder to crush. It also costs more and takes a little more room, so the question is never "which is stronger" — it's whether your load needs the extra strength.
Honest answer: most parcels are fine in single wall
A 32 ECT single-wall box handles the typical e-commerce parcel — clothing, housewares, electronics in their retail packaging — without drama. If your packed box is a comfortable one-person lift, travels by parcel carrier, and isn't stacked five-high for months, single wall is the economical, correct choice.
When double wall earns its cost
Three situations justify the upgrade. Heavy or dense contents: hardware, tile, books by the case, anything that visibly strains a single-wall box. Stacking strength: boxes at the bottom of a tall pallet or warehouse stack take the whole column's weight on their edges. Long storage: board slowly loses stiffness with time and humidity, and double wall has more reserve to lose.
Fragile contents
Double wall is also the right shell for very breakable items, because a stiffer box transmits less of an impact to what's inside. Pair it with the rest of the fragile playbook — two inches of cushioning on every side, individually wrapped items, void fill so nothing shifts — from our guide on packing fragile items. The board grades are explained in detail in the ECT and box strength guide.
How to decide on a real order
Weigh your packed box, then check the board grade on the product page — every box in the catalog shows its wall type and ECT rating, so the comparison takes seconds. If you're near the single-wall limit, or the boxes will be stacked or stored, step up. If you're well under, keep the savings.
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FAQ
How do I know if I need double wall?
Weigh a packed box: if it's notably heavy or dense for its size, or the box will be stacked or stored long-term, step up to a higher ECT or double wall. High stacking, long storage, freight transit, and very fragile contents all favor double wall. Normal parcel handling with a comfortable lift? Single wall is fine.
Is double wall worth it for moving?
For the heavy boxes — books, dishes, tools — and anything going into storage, yes: double wall resists crushing at the bottom of a stack. Clothes, linens and light household goods move safely in standard single wall.
Do double wall boxes have weight limits too?
Yes. Double wall raises the ceiling, it doesn't remove it. Every product page lists the wall type and ECT rating for that exact box — heavier loads belong in higher grades rather than hoping a light-duty box holds.