Void Fill vs. Blocking & Bracing: Choosing the Right Protection

We have all received that one package. You pick it up off your porch, give it a slight shake, and hear the ominous sound of the item inside bouncing off the cardboard walls. 

That sound is the sound of a packaging failure. 

When it comes to protective packaging, there is no "one size fits all" solution. Two of the most common methods—Void Fill and Blocking & Bracing—are often used interchangeably, but they serve very different engineering purposes. Using the wrong one can lead to damaged goods, unhappy customers, and wasted budgets 

Here is how to distinguish between the two and choose the right method for your shipment.

1. Void Fill: The "Seatbelt"

The Goal: To restrict movement by filling the empty space inside the box 

If you put a small item in a large box, it will migrate during transit. Void fill is designed to occupy that excess space, ensuring the product stays relatively centered and doesn't bounce around.

Common Inflatable Materials:

• Air Pillows: Lightweight and clean. They add almost zero weight to the shipment, keeping freight costs down.
• Crumpled Paper: Versatile and eco-friendly. It can conform to irregular shapes. 

When to Use Void Fill:

• Light to Medium Weight Items: Ideal for clothing, cosmetics, small electronics, or pre-packaged goods that just need to be kept stationary.
• Irregular Shapes: When the product doesn't sit, flush against the box walls.
• Top Filling: Placing a layer of protection on top of the product before sealing the flaps.

The Limitation: Void fill is not structural. If you throw a 50lb motor into a box and surround it with air pillows, the heavy motor will likely crush the pillows during a drop, hit the side of the box, and cause damage.

2. Blocking & Bracing: The "Anchor" 

The Goal: To immobilize the product and create a structural barrier against impact

Blocking and bracing isn't just about filling space; it is about creating a rigid structure that locks the product into place. It prevents the item from moving at all, even if the box is dropped or turned upside down. It also creates a buffer zone (crush zone) that absorbs impact energy before it reaches the product.

Common Materials:

• Heavy-Weight Paper Pads: Multi-ply paper that is crimped to create a dense, shock-absorbing pad.
• Foam Planks/Inserts: Versatile and eco-friendly. It can conform to irregular shapes.
• Corrugated Inserts: Folded cardboard designed to hold a product in the center of the box.

When to Use Blocking & Bracing:

• Heavy or Industrial Items: Auto parts, motors, pumps, and heavy machinery parts need rigid support.
• Fragile/Breakable Items: Glass, ceramics, or sensitive electronics where any migration could cause breakage.
• Sharp Edges: Heavy metal parts with sharp corners will pop air pillows; thick paper pads or foam can withstand the abrasion.

The Decision Matrix: Which one do you need?
To decide between the two, ask yourself these three questions:

1. Does the product weigh more than 15 lbs?
• Yes: Lean toward Blocking & Bracing. Heavy items generate high kinetic energy when dropped; you need dense material to absorb that shock.
• No: Void Fill is likely sufficient.
2. Is the product fragile?
• Yes: Blocking & Bracing. You need to ensure the product never touches the outer wall of the box.
• No: Void Fill will stop it from rattling.
3. Are you worried about shipping costs (DIM Weight)?
• Yes: Void Fill (specifically air pillows) is generally lighter and uses less volume than heavy paper pads or foam.
  
  

The IPG Solution 

Whether you need the featherlight protection of the AirSpace system for your e-commerce fulfillment or the rugged protection of PaperSpace Paper Packaging Systems for your industrial shipments, we have the machinery and materials to match the application.

Stop the rattle. Protect the product.

Explore IPG’s Protective Packaging Solutions