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Underhang—the opposite of overhang. Your product footprint is smaller than the slip sheet, leaving exposed sheet edges extending beyond the product.
Maybe you’ve got a 40×36″ load on a 48×40″ slip sheet. Or 42×38″ cases on a 48×48″ sheet. The product sits entirely on the slip sheet with 4-8 inches of exposed sheet around the perimeter.
You’re wondering: Is this a problem? Does the exposed slip sheet create handling issues or waste material?
Here’s the truth: Underhang generally works fine and is often intentional for handling benefits—but excessive underhang wastes material and can create minor handling annoyances.
Let me explain when underhang makes sense, how much is appropriate, and when to right-size your slip sheets instead.
Understanding Underhang vs. Overhang
First, clarify the difference since they’re opposite scenarios.
Overhang (covered in Article 32): Product extends beyond slip sheet edges. Creates stability and handling problems. Generally undesirable.
Underhang (this article): Slip sheet extends beyond product edges. Creates exposed sheet border around product. Generally acceptable or even beneficial in moderation.
The physics: Underhang provides full support for product (entire load sits on sheet). No unsupported product edges or corners. Exposed sheet edges available for handling if needed.
Why Underhang Is Often Intentional
Moderate underhang provides handling advantages.
Benefits of 2-4 inch underhang: Provides gripping surface for push-pull attachment: Clamps or jaws engage exposed sheet edges for secure handling. Allows forklift tines to contact sheet without hitting product: Easier initial engagement during loading. Creates visual identification: Clear sight line to slip sheet edges aids operators. Provides safety margin: Slight product size variations won’t create overhang. Accommodates stretch wrap tail: Wrap tail has substrate to adhere to beyond product.
Industry practice: 2-3 inches of underhang on push-pull approach side is common and often recommended. Provides ideal attachment engagement without excessive material waste.
Acceptable Underhang Amounts
How much underhang is reasonable?
General guidelines: 1-2 inches: Minimal underhang, provides slight margin for variation. Perfectly acceptable.
2-4 inches: Moderate underhang, provides good handling benefits. Optimal range for push-pull engagement.
4-6 inches: Significant underhang, starting to waste material. Acceptable if handling benefits justify or if using standard sheet sizes for variable loads.
6+ inches: Excessive underhang, material waste becomes substantial. Should consider custom-sized sheets.
These are per-side measurements. Total underhang is double (4 inches per side = 8 inches total dimension difference).
When Underhang Creates Problems
Excessive underhang has downsides.
Issues with large underhang: Material waste: Paying for slip sheet area not supporting product. Freight inefficiency: Shipping air space around underhanging loads. Handling annoyances: Long exposed edges may flop, fold, or get caught during handling. Stretch wrap complications: Excessive exposed sheet may interfere with wrapping. Cost: Each inch of unnecessary dimension adds ~4% to sheet cost.
Example: 40×36″ load on 48×40″ slip sheet = 20% material waste compared to 42×38″ custom sheet.
Solution 1: Right-Size Slip Sheets
For consistent loads, use appropriately-sized sheets.
Custom sizing approach: Measure actual product footprint. Add 2-3 inches per side for handling margin. Order custom slip sheets in that size. Eliminates waste while maintaining handling benefits.
Example: 40×36″ product. Add 3 inches per side for handling. Order 46×42″ custom slip sheets. Provides ideal 3-inch underhang without excessive waste.
Custom sizing economics: Minimum quantities: Typically 500-1,000 sheets for custom sizes. Lead time: 2-4 weeks typical vs. stock standard sizes. Cost premium: 10-20% over standard sizes. Break-even: If your volume is 1,000+ sheets annually, custom sizing often pays off through material savings.
Call or Text us at 832.400.1394 for a Quote!
Solution 2: Use Standard Sizes Strategically
Match standard sheet sizes to product as closely as possible.
Standard size selection: For 40×36″ product: Use 42×42″ sheet (2-3 inch underhang) rather than 48×48″ (4-6 inch underhang). For 44×38″ product: Use 48×40″ sheet (2-4 inch underhang on different dimensions). For 36×30″ product: Use 40×32″ half-pallet sheet if available.
This minimizes underhang waste while using readily-available standard sizes.
Solution 3: Variable Load Strategy
If product sizes vary, moderate underhang accommodates flexibility.
Variable sizing benefits: One slip sheet size handles multiple product footprints. 48×40″ sheet works for 40×36″, 42×38″, 44×36″ loads etc. Simplified inventory (one sheet size vs. multiple custom sizes). Operational flexibility for mixed loads.
Trade-off: Some material waste on smaller loads vs. inventory and operational complexity of custom sizes.
For operations with significant product variation, standard sheets with moderate underhang make sense.
Push-Pull Attachment Engagement
Underhang affects handling technique.
Engagement with underhang: 2-4 inch underhang: Ideal for attachment engagement. Provides clear gripping surface. Attachment jaws or clamps engage sheet without contacting product.
Minimal underhang (<1 inch): Requires precise attachment positioning. Risk of contacting product if alignment isn’t perfect. Still workable but less margin for error.
Excessive underhang (6+ inches): Attachment may grip too much sheet, causing folding or bunching. Longer exposed edges may flop during handling.
Optimal underhang for push-pull handling is 2-4 inches on approach side.
Stretch Wrapping Considerations
Underhang interacts with stretch wrapping.
Wrapping with underhang: Moderate underhang (2-4 inches): Provides substrate for wrap tail adhesion. Wrap can extend to sheet edges for full containment. Creates clean wrapped appearance.
Excessive underhang (6+ inches): Exposed sheet may flop outside wrap zone. Wrap may not cover sheet edges, leaving loose material. Appearance less professional.
Minimal underhang (<1 inch): Wrap must precisely cover product edges without much margin. Product edges more vulnerable if wrap doesn’t extend fully.
Freight and Storage Efficiency
Underhang affects space utilization.
Efficiency impact: Each inch of underhang per side reduces freight cube efficiency. 4 inches total underhang per side (8 inches in each dimension) = ~15% space waste in trucks/containers. More significant for ocean freight where cube optimization matters. Less important for domestic truck freight where weight often fills truck before cube.
For export applications where container space is premium, minimizing underhang through custom sizing provides real value.
Material Cost Considerations
Quantify the cost of underhang.
Cost calculation: 40×36″ product on 48×40″ slip sheet: Sheet cost: $6. Appropriate custom 46×42″ sheet: $6.80 (13% premium for custom size). Material savings per sheet: None initially (custom costs more). But custom sheet uses 10% less material overall. At high volume (5,000+ sheets/year): Custom sizing savings overcome premium through reduced material.
Run the numbers for your specific volumes.
When Underhang Makes Sense
Acceptable and beneficial underhang scenarios: Variable product sizes using standard sheet sizes for flexibility. Intentional 2-4 inch underhang for push-pull handling benefits. Products slightly smaller than standard sheets where custom sizing isn’t justified. Trial or sampling with standard sheets before committing to custom. Low-volume applications where custom sizing minimums don’t make sense.
When to Eliminate Underhang
Custom sizing makes sense when: Consistent product size with high volume (1,000+ sheets/year). Export applications where cube optimization matters. Excessive underhang (6+ inches) creating significant waste. Multiple products that could consolidate to one custom size. Material cost reduction justifies custom sizing premium.
Real-World Example: Consumer Products
Consumer packaged goods often have slight underhang.
Typical scenario: Product: 42×38″ footprint. Slip sheet: 48×40″ (standard size). Underhang: 3 inches on length, 1 inch on width. Volume: 2,000 sheets/year.
Analysis: Underhang is modest and provides handling benefits. Product variation might occasionally be 42×40″ or 44×38″ (standard sheet accommodates). Custom 46×42″ sizing would save material but adds complexity. Decision: Stick with standard 48×40″ sheets. Modest underhang is acceptable trade-off for operational simplicity.
What Custom Packaging Products Recommends
We help customers optimize slip sheet sizing.
Our recommendations: 2-4 inches underhang is ideal for handling and acceptable material use. 6+ inches underhang justifies evaluation of custom sizing. For consistent high-volume applications, custom sizing to minimize underhang often pays off. For variable products or low volume, standard sizes with moderate underhang make sense. We can manufacture custom sizes (1,000+ sheet minimums typically) to match your product footprint.
We’ll help you analyze whether custom sizing or standard sheets with underhang make more economic sense.
The Bottom Line
Slip sheets handle underhang loads perfectly well—in fact, 2-4 inches of underhang on the push-pull approach side is often beneficial for handling.
Moderate underhang (2-4 inches) provides gripping surface for attachments, accommodates product variation, and creates handling margin. Excessive underhang (6+ inches) wastes material and may justify custom slip sheet sizing for high-volume consistent applications.
Unlike overhang which creates stability and handling problems, underhang is generally acceptable and often intentional.
At Custom Packaging Products, we manufacture both standard and custom-sized slip sheets to match your product footprint and optimize material use while maintaining handling benefits.
Call or Text us at 832.400.1394 for a Quote!
Describe your product dimensions and volume. We’ll recommend whether standard sheets with moderate underhang or custom sizing makes more sense economically.
Underhang is fine—often it’s actually desirable.