Pallet types
Perimeter base pallet: a block pallet with a framed bottom
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A perimeter base pallet is a block pallet whose bottom deck runs around all four edges like a picture frame, so the pallet bears on a continuous rectangle. The metric 1200 x 1000 mm block pallet is commonly built this way, and it is the default bottom in palletdesign.ai's 48 x 40 block template.
On this page
What is a perimeter base?
The Uniform Standard lists several bottom-deck constructions for block pallets. A perimeter base has bottom boards along all four edges, forming a frame (sometimes called a picture-frame base). The pallet sits on a continuous rectangle of wood rather than on parallel strips.
| Bottom style | Layout | Pallet jack from sides |
|---|---|---|
| Perimeter | Frame on all four edges | Limited: wheels must clear the frame |
| Unidirectional | Boards in one direction only | Yes, from the open direction |
| Cruciform | Perimeter plus center boards in both directions | Limited |
| Overlap (partial 4-way) | Bottom deckboards plus bottom stringerboards | No |
How a perimeter base pallet is built
From top down: top deckboards, three stringerboards, nine blocks, then the bottom frame. palletdesign.ai builds the frame from two full-length side boards under the outer block rows plus three cross boards, one under each block row, fitted between them. Its starting 48 x 40 template uses 3/4 in bottom boards 5-1/2 in wide; every size is editable.
The published PDS block-class guide uses a 1200 x 1000 mm perimeter base pallet as its worked example, and the UK standard pallet on the same footprint is a perimeter base design. Among CP pallets, CP6 to CP9 have perimeter or frame bottoms.
Fasteners follow block-pallet rules: the Uniform Standard calls for at least 3 fasteners at each corner block and 2 at each interior block.
When to use a perimeter base
- Stacking loaded pallets: the frame spreads the upper pallet's load onto the one below along all four edges.
- Conveyors in either direction: there are bottom boards running both ways, so the pallet has something to ride on whichever way it travels.
- Racking in either direction, subject to a rating for each.
- Pallets that are handled mainly by forklift, which enters all four sides.
When not to use one
- Side entry with pallet jacks. The wheels need to reach the floor between bottom boards. If jacks enter from the sides, a unidirectional base is the usual choice. The designer flags this combination and suggests switching.
- Lowest-cost builds. The frame uses more bottom lumber and fasteners than a unidirectional base.
Perimeter base vs unidirectional base
| Perimeter base | Unidirectional base | |
|---|---|---|
| Bottom boards | All four edges | One direction only |
| Bearing when stacked | Continuous frame | Parallel strips |
| Conveyor travel | Either direction | Across the boards |
| Pallet jack from sides | Limited | Yes, from the open direction |
| Example | 1200 x 1000 block, CP6 to CP9 | EPAL 1 (bottom boards run the 1200 mm length) |
How to specify a perimeter base pallet
- Size and top deckboard direction.
- Top deck: count, thickness, widths.
- Stringerboards and blocks: sizes and material.
- Bottom: "perimeter base", with board thickness and widths for each side.
- Chamfers on bottom boards if pallet jacks are used from the ends.
- Fasteners for mat, top-to-block and bottom-to-block connections.
- Load, stacking height, rack direction and conveyor direction.
See the 48 x 40 block pallet and 1200 x 1000 pages for drawings, and pallet jack compatibility for wheel-opening dimensions.
Questions
- What is a perimeter base pallet?
- A block pallet whose bottom boards run around all four edges, forming a frame, so the pallet bears on a continuous rectangle.
- Can a pallet jack lift a perimeter base pallet?
- From the ends, typically yes. From the sides the wheels must clear the frame, so if jacks enter from the sides, a unidirectional base is usually specified.
- What is the difference between perimeter and cruciform bases?
- A cruciform base adds center boards in both directions to the perimeter frame, giving more bottom support at the center.