Poor packing is the single most common cause of damage in granite shipments. Slabs that are not properly packed will shift during transit, crack under their own weight, or arrive with surface damage from contact with other slabs. Understanding how your granite should be packed gives you the tools to specify correctly and identify substandard packing before your shipment departs.
The Two Primary Packing Methods
Method 1: Wooden Crate (Bundle) Packing
Wooden crate packing is the standard method for most granite slab shipments. Slabs are stacked vertically (on edge, not flat) in a rigid wooden frame, interleaved with foam padding between each slab.
Construction requirements for ISPM 15 compliance:
- All timber used in crate construction must be heat-treated or fumigated to ISPM 15 standard (prevents pest import)
- ISPM 15 mark must be stamped on all four sides of the crate
- Crates must be structurally rigid — no flex that could allow slab movement
- Base runners must be robust enough to support forklift entry from both directions
Method 2: C-Clamp Container Loading
C-Clamp loading uses a specialised steel frame that holds slab bundles at an angle within the container, using the container walls for support. This method is preferred for large format slabs and high-value shipments.
Advantages of C-Clamp loading:
- Slabs are secured at an angle, using gravity and the container wall for support
- Significantly less movement during transit compared to crate-only loading
- Allows better use of container volume for large format slabs
- Industry-standard for premium granite exports to Europe and North America
Foam Interleaving: Why It Matters
Every slab in a bundle must be separated from its neighbours with protective foam. The foam serves two purposes: it prevents surface-to-surface contact that would cause scratching, and it absorbs vibration and minor impacts during transit.
| Foam Type | Application | Notes |
|---|---|---|
| Polyethylene foam sheets | Between polished slabs | Non-abrasive — won't scratch polished surface |
| Bubble wrap | Around individual slabs | Additional protection for high-value stones |
| Cardboard corners | Slab corners and edges | Prevents corner chips during handling |
Container Loading and Stowage
How slabs are loaded into the container is as important as the crate construction:
- Slabs must always be stored and transported on edge (vertically), never flat — flat storage causes bending stress that can crack even thick slabs
- Heavier slabs/varieties should be positioned at the back and bottom of the container
- All void spaces must be filled with dunnage (timber blocking) to prevent movement
- Container doors must be blockable — the cargo should not shift toward the doors during deceleration