Single wall suits lighter goods that travel as parcels and are not stacked heavily. Double wall suits heavier contents, taller stacks and longer or rougher journeys. The decision should be driven by the load above the carton as much as by the weight inside it - which is the factor most often missed.
What the terms actually describe
Corrugated board is made of fluted paper sandwiched between liners. Single wall is one fluted layer between two liners. Double wall is two fluted layers with a liner between them and one on each face. Triple wall adds a third.
More layers means more strength, more board cost, more thickness and more weight. Thickness matters more than people expect, because it changes the external dimension for the same internal volume - which can push a pack into a different carrier band.
The question that actually decides it
Most people choose board grade by thinking about the weight of the contents. That is half the question, and usually the less important half.
What crushes cartons in practice is the load above them - in a pallet stack, in a cage, in a warehouse rack. A carton can be perfectly adequate for its own contents and collapse under four others on a pallet.
So the specification question is: how heavy is what goes inside, and what will be stacked on top, how high, and for how long?
A practical comparison
| Factor | Single wall | Double wall |
|---|---|---|
| Contents weight | Lighter items | Heavier items |
| Stack load | Light stacking only | Designed for stacking |
| Journey | Parcel network, short handling chains | Pallet, long chains, international |
| Board cost | Lower | Higher |
| Thickness and external size | Thinner - better for carrier bands | Thicker - can push a band |
| Weight of the pack itself | Lighter | Heavier - affects weight bands |
| Storage dwell | Short | Tolerates longer dwell and humidity better |
Choosing between constructions.
The two expensive mistakes
- Under-specifying for the stack. The saving appears immediately on the invoice; the crushed cartons appear a month later at the bottom of a pallet. This is the more common of the two.
- Over-specifying across the range. Double wall everywhere is an easy decision and a permanent cost on every unit, including the lines that never needed it.
Both come from making one board decision for a mixed range rather than specifying by SKU group - see packaging materials.
Where triple wall comes in
Triple wall is for genuinely heavy or high-value industrial goods - machinery parts, fabricated assemblies, anything where a timber case would otherwise be considered.
It is frequently a lighter and cheaper alternative to a timber case, and avoids the treatment and certification requirements timber carries. See industrial packaging.
Things that change the answer
- Humidity and dwell. Board loses compression strength in damp conditions and over time. Long storage or a marine journey may justify a grade up.
- Recycled content. Different liner grades perform differently; the specification should be by performance, not just by wall count.
- Box format. A full overlap or crash-lock base adds strength at the weakest point and can allow a lighter board.
- What is inside. A fitted insert that carries some of the load can let the outer be lighter.
How to get it right without over-engineering
- Group SKUs by weight and by how they are stacked.
- For each group, state the stack height and dwell time.
- Specify board to that, not to the contents alone.
- Check what the resulting thickness does to your carrier band fit.
- Sample and test a full stack where the load is significant.
If cartons are crushing now, that is a specification problem rather than a handling problem, and it is solvable - see protective packaging.
The short version
- What crushes a carton is the load above it, not the contents inside.
- Under-specifying for the stack shows up a month later at the bottom of a pallet.
- Double wall everywhere is an easy decision and a permanent cost.
- Thickness changes external dimensions and can push a carrier band.
- Humidity and dwell reduce compression strength - allow for both.
Frequently asked questions
Is double wall always stronger?
In compression terms generally yes, but 'stronger' is not the only consideration - it is thicker, heavier and more expensive, and the extra thickness can push a pack into a worse carrier band.
Our cartons keep crushing. Should we go double wall?
Possibly, but check the stack first. Crushing is usually a stack-load specification problem, and corner boards or a different pallet build sometimes solve it more cheaply.
Can we use single wall for ecommerce parcels?
Frequently yes, for lighter goods - parcels are not heavily stacked for long. The failure mode in a parcel network is usually movement rather than compression.
Does recycled board affect the decision?
It can, because liner grades differ in performance. Specify by what the board has to do rather than by wall count alone.
How do we avoid over-specifying?
Specify by SKU group rather than making one board decision for the whole range. Double wall everywhere is easy and costs money on every unit that did not need it.