Perimeter base pallet: a block pallet with a framed bottom
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.
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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.
Related
- Block pallet: how it's built and when it beats a stringer palletA block pallet rests on 9 blocks joined by stringerboards, giving full 4-way fork entry. See how it is built, when to use it and what a quote needs.
- Perimeter baseA perimeter base is a block-pallet bottom with boards around all four edges, like a picture frame. It gives full four-way forklift and pallet-jack entry.
- Unidirectional baseA unidirectional base is a block-pallet bottom whose boards all run in one direction, with no crosswise bottom boards, giving full four-way pallet-jack entry.
- 1200 × 1000 mm pallet1200 × 1000 mm (47.2 × 39.4 in) pallet specs with drawings: block pallet 51 lb. Nail counts, board feet and parts lists for each build.
- Pallet jack compatibility: which pallets work with a pallet jackPallet jack compatibility: stringer pallets take jacks from the ends only, even when notched; block pallets allow more faces, set by the bottom deck.
- Panel deck pallet: plywood and OSB decksA panel deck pallet uses plywood or OSB instead of deckboards. Uniform Standard rules on grade, grain and strip width, ISPM 15 notes, and how to specify one.