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Foam blocks are solid blocks of foam used across construction, packaging, furniture and arts and crafts. Foam is formed by trapping pockets of gas in a liquid or solid material, so foam blocks are lightweight, durable and easy to cut into different shapes and sizes.
The type of foam used in a block can vary, and each offers different properties, from high-density foams, which are strong and durable, to low-density foams, which are soft and flexible. Understanding these differences is key to choosing the right foam block for your needs.
| Foam Type | Cell Structure | Key Properties | Typical Uses |
|---|---|---|---|
| Polyurethane | Flexible, open-cell | Wide range of densities and firmness; easy to cut and shape | Cushioning, padding, packaging, soundproofing |
| Polystyrene | Rigid, closed-cell | Lightweight, moisture-resistant, good thermal insulation | Building insulation, protective packaging, crafts |
| Memory Foam | Viscoelastic polyurethane | Deforms under pressure and slowly recovers | Bedding, furniture, pressure-relief products |
Foam blocks can be made from several types of foam, and the type used has a significant impact on the block’s performance and suitability for different applications. The most common are polyurethane foam, polystyrene foam and memory foam.
Flexible polyurethane foam is an open-cell foam that can be produced in a wide range of densities and firmness levels. This makes it suitable for everything from cushioning and padding to insulation and soundproofing.
Polyurethane foam blocks are lightweight and durable, making them well suited to packaging and shipping. They can also be easily cut and shaped, making them a popular choice for upholstery and craft projects.
Polystyrene foam (sometimes referred to by the brand name Styrofoam) is a rigid, closed-cell foam known for its excellent insulation properties. It is lightweight, resistant to moisture and can be produced in a range of densities.
Polystyrene foam blocks are commonly used as insulation in construction. They are also used in packaging, where their light weight and durability help protect delicate items during shipping.
Memory foam is a type of polyurethane foam with viscoelastic properties: it deforms under pressure and then slowly returns to its original shape once the pressure is removed. This makes it an excellent material for cushioning and support.
Memory foam blocks are commonly used in bedding and furniture, where they provide comfort and support. They are also used in healthcare products designed to help relieve pressure points.
The application of a foam block usually dictates the type of foam used, as well as the size and shape of the block. For example, high-density rigid foam blocks may be used in construction for insulation and structural support, while low-density blocks are often used in arts and crafts, where they can be easily cut and shaped. See our foam applications guide for more examples.
In construction, foam blocks are widely used as foam insulation. They are lightweight and easy to install, and they offer good thermal and acoustic insulation. Rigid polystyrene foam blocks are particularly popular in this application.
Foam blocks can also be used structurally. For example, insulated concrete forms (ICFs) use foam blocks as formwork for concrete: the foam provides insulation, while the concrete provides strength and durability.
In foam packaging, foam blocks protect delicate items during shipping. They are lightweight and durable, and they can be easily cut and shaped to fit a wide range of items.
High-density polyurethane foam blocks are particularly popular for this purpose. They offer excellent shock absorption, making them ideal for protecting delicate items such as electronics or glassware.
Foam blocks are a popular material in arts and crafts, as they are lightweight, easy to work with and can be cut and shaped into a wide range of forms.
Low-density foam blocks are particularly popular. Polystyrene blocks are usually cut with a hot wire cutter, while flexible polyurethane foam is best cut with a sharp knife, and both can be painted or decorated.
The properties of a foam block depend on the type of foam used, as well as its density and firmness. Key properties include light weight, durability, ease of cutting and shaping, and good insulation. Our foam properties overview explains these in more detail.
Because foam is made by trapping pockets of gas in a liquid or solid, it is largely composed of air. This makes foam blocks lightweight and easy to handle.
Their light weight also makes foam blocks ideal for packaging, where they protect delicate items without adding significant weight, helping to reduce shipping costs and make handling easier.
Foam blocks are resistant to many common forms of damage, including impact and moisture, making them suitable for a wide range of applications. However, most foams should be protected from prolonged exposure to direct sunlight, as UV light can cause them to discolour and degrade.
Durability varies with the type of foam used. For example, high-density foam blocks are typically more durable than low-density blocks. See our guide to foam durability for more on what makes foam last.
Foam blocks trap air within their structure, which reduces the transfer of heat. This makes them an excellent material for insulation in construction and packaging.
Insulation performance varies with the type of foam. Closed-cell foams, such as polystyrene, generally insulate better than open-cell foams, such as flexible polyurethane.
The manufacturing process varies depending on the type of foam, but typically involves expanding a liquid or solid material to create a foam, which is then cut into blocks. The process has a significant impact on the block’s density, firmness and insulation properties. Our foam manufacturing guide covers this in more detail.
The first step is to expand a liquid or solid material into a foam by introducing gas into it. The amount of gas (blowing agent) and the processing conditions have a significant impact on the foam’s properties. In general, more gas produces a lighter, lower-density foam.
Once the foam has formed, it is left to cure so that its structure stabilises and sets. The curing process affects properties such as firmness and durability, and varies by foam type. Polyurethane foam cures through the heat of its own chemical reaction, while polystyrene blocks are typically moulded from expanded beads using steam and pressure.
Once cured, the foam is cut into blocks. Polystyrene is typically cut with hot wire cutters, while flexible polyurethane foam is cut with blade-based equipment such as band knives. The size and shape of the blocks can be easily adjusted to suit different applications. See our guide to foam cutting for more on the methods used.
Like all products, foam blocks have an environmental impact, from the resources used in manufacturing to disposal at the end of their life. However, many types of foam can be recycled, and some foams now include recycled or bio-based content.
Manufacturing foam blocks consumes energy and raw materials, many of which are non-renewable. Many manufacturers are taking steps to reduce this impact, including using recycled materials and more energy-efficient processes.
Foam blocks made from non-biodegradable materials can take a long time to break down if they are not disposed of properly. Recycling helps to reduce this impact at the end of their life.
Many types of foam can be reprocessed into new products, reducing the need for new raw materials and the amount of waste sent to landfill. Collection schemes and recycling facilities help to increase recycling rates. Our foam recycling guide explains how this works.
Foam blocks are a versatile product used across a wide range of industries, offering light weight, durability and good insulation. Like all products, they have an environmental impact, so it is worth considering this when choosing a foam block, for example, by choosing blocks with recycled content and making sure used foam is disposed of or recycled properly.
Continue exploring foam formats, specifications and processes across our technical glossary:
Whether you need a foam block for replacement cushions, packaging inserts or a craft project, the Foam & Covers team can help you choose the right foam and cut it precisely to your measurements.
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