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Corrugated board grades refer to the different types of cardboard used in packaging, determined by the thickness and strength of the material. These grades range from single-face (one layer of corrugated material) to triple-wall (three layers), with common grades like single-wall and double-wall in between. The more layers, the stronger and thicker the board is, making it suitable for heavier or more fragile items. Essentially, think of it as choosing between a light, medium, or heavy-duty box depending on how much protection your item needs.

How many layers are there in a piece of cardboard?
Corrugated board or cardboard is typically made up of three to seven layers, depending on its grade and intended use. The outside layers are called liners and the inside layer is called a flute or fluting.

What is a Flute?
In the context of corrugated cardboard, the flute refers to the wavy, arch-like layer sandwiched between the flat layers (liners) of the board. This wavy structure is what gives corrugated cardboard its strength and rigidity.

What is known as Kraft?
Kraft refers to the type of paper used to make the outer liners and sometimes the inner fluting of the board.

What is known as Test?
Test refers to testliner, which is a type of paper used for the liners (flat layers) in corrugated board. Testliner is typically made from recycled paper fibres and is considered a cost-effective and sustainable option compared to virgin kraft paper.

If you want to know more about how Corrugated Cardboard is sustainable, click to read 5 Reasons Corrugated Cardboard is an environmentally-friendly packaging material.

Single Flute Board Grades

A-Flute: Largest flute size, offering excellent cushioning and stacking strength. Often used for fragile items and industrial applications.

B-Flute: Medium flute size, providing good puncture resistance and a flatter surface for printing. Common for retail packaging and canned goods.

C-Flute: Versatile flute size that combines good cushioning with surface smoothness. Widely used for shipping and packaging a variety of products.

E-Flute: Smaller flute size, offering a smooth surface for high-quality printing and better foldability. Ideal for retail packaging, displays, and smaller boxes.

F-Flute: The smallest flute size, providing a very smooth surface for high-quality graphics. Used for lightweight packaging and small retail boxes.

Combining Board Grades
Boards can combine different flute types to optimise properties for specific uses, such as BC-Flute (a combination of B and C flutes) or BE-Flute (a combination of B and E flutes).

Each grade offers a unique balance of strength, weight, and printability, making it crucial to choose the right type for the specific packaging needs. Our most typical double wall flute sizing’s are “BC” and “EB”.

Sandland Board grades

Combining different flute types in double or triple wall boards enhances specific properties, such as strength, cushioning, or surface smoothness. Here are the differences between our most popular flute combinations.

BC-Flute (Double Wall with B and C flutes)
Use: Provides excellent stacking strength and cushioning, ideal for products that are both heavy and fragile.
Examples: Furniture, electronics, and large automotive parts.

EB-Flute (Double Wall with E and B flutes)
Use: Combines a smooth surface for printing (E-flute) with strength and puncture resistance (B-flute). Often used for retail packaging and point-of-sale displays.
Examples: Display boxes, retail packaging for fragile items like electronics, and promotional materials.

Different combinations are tailored for specific industries. For example, BC-Flute might be used in the automotive industry for parts, while EB-Flute is favoured in retail for attractive display packaging. Double and triple wall boards are commonly chosen for export packaging due to their ability to withstand rough handling and long transportation.

By selecting the appropriate board grade and combination, businesses can optimise protection, cost, and branding for their products.



Choosing the right cardboard grade is crucial for ensuring that your products are protected effectively during shipping and handling. Different grades offer varying levels of strength, cushioning, and durability, tailored to the specific needs of the items being packaged. For instance, lighter single-wall boards are perfect for standard, lightweight goods, while double or triple-wall boards provide the necessary robustness for heavy or fragile items.

Selecting the appropriate grade not only safeguards your products but also optimises cost efficiency and enhances your brand’s sustainability efforts. By matching the cardboard grade to your packaging requirements, you ensure that your products reach their destination safely and intact, maintaining customer satisfaction and minimising potential damage-related costs.

Need Help with choosing the right material / board grade?
Our friendly team is here to help. Call us now on 01902 496 925 for your free packaging quote