Corrugated Grades Explained for Long Cardboard Packaging
Board grade selection for long boxes: why getting it right matters more than with standard packaging.
Why grade matters more for long boxes
Long boxes amplify every weakness in the board. A grade that performs perfectly in a 30cm box may fail in a 120cm box because the unsupported centre span creates leverage that multiplies stress. Choosing the right grade is more critical for long boxes than any other packaging format.
Quick answer
B-flute single-wall for long boxes under 80cm with light contents. BC or EB double-wall for boxes 80cm-1.5m. Heavy-duty double-wall with 200gsm+ liners for boxes over 1.5m or heavy items. The key metric is rigidity across the span, not just compression strength. Test by holding a sample box by one end - if it sags more than 5-10cm, upgrade the board grade.
Flute types for long boxes
Good rigidity for light items in shorter elongated formats.
Good balance of rigidity and impact protection.
Two flute layers provide the rigidity needed to prevent centre-span sag.
Thicker liners (200gsm+) and BC or BE flute for maximum performance.
Liner weights
For long boxes, heavier liners significantly improve span rigidity. Standard 125gsm liners work for short boxes but 150-200gsm kraft liners are recommended for boxes over 1m. The outer liner also affects print quality - white-lined board prints better than brown kraft.
Related: single vs double wall or reinforcement techniques.
Choosing the right grade
Grade selection0 / 4 checked
Long boxes in every grade
ProcuraPack offers long cardboard boxes from single-wall to heavy-duty double-wall.
Browse long boxesFrequently asked questions
BC double-wall for boxes over 80cm. Single-wall B-flute only for shorter, lighter applications.
The unsupported centre span creates leverage that amplifies stress beyond what standard grades handle.
150gsm minimum for boxes over 1m. 200gsm+ for heavy items or boxes over 1.5m.
Hold a loaded sample by one end. If it sags more than 5-10cm, upgrade the grade.
Only for very short (under 50cm) and very light items. It lacks the rigidity for longer spans.
Part of our guide
Product Guide: Long Cardboard Boxes
Expert guides on long cardboard boxes for shipping oversized, elongated, and awkward items safely.
Browse all guides →
