EPS vs. PU Foam Surfboard Blanks: Key Differences and How They're Made

Discover the key differences between EPS and PU surfboard blanks, learn how each impacts performance, shaping, and sustainability.

When it comes to surfboard construction, the choice of the right “ blank” (surfboard foam) plays a significant role in shaping the board's performance, durability, and environmental impact. Two of the most common materials for surfboard blanks are Polyurethane (PU) Foam and Expanded Polystyrene (EPS). Among these, PU foam is by far the most used and trusted material in the industry, favored by both shapers and surfers for its performance, versatility, and classic feel.

Although there are no official numbers or studies available we estimate that at least 80 % of all surfboards (not soft tops) are made from polyurethane foam. It’s the preferred choice to work with and creates a unique feeling in the water and this is why at Polyola, we focus exclusively on PU foam blanks. Our formulation for the manufacturing of PU foam blanks is leading the way in sustainability, being created from from 2/3 recycled materials. These blanks, manufactured by Arctic Foam, reduce CO₂ emissions by 73% while maintaining 100% performance, offering surfers and shapers an environmentally responsible choice without compromise.

So, let’s take a closer look and briefly compare the two materials to understand their differences and why PU foam continues to lead the industry.

What is PU Foam, and How is it Made?

Polyurethane (PU) Foam has been the cornerstone of surfboard construction for decades. Its unmatched shaping properties and performance characteristics have made it the go-to material for the vast majority of boards worldwide.

Simplified Production Process of PU Foam Blanks:

1. Mixing Chemicals: PU blanks are made by mixing polyol and isocyanate, in most cases in a very hands-on manual process.
2. Foaming Reaction: The mixture is poured with a specific pattern into a mold and expands through a chemical reaction thereby turning the liquid matter into rigid polyurethane foam.
3. Curing and Hardening: After the rigid foam blanks is created inside the mold it usually gets put into a heating chamber to cure.
4. Stringer Insertion: Once the blank is fully cured, it is cut in half, and in most cases a wooden stringer (typically plywood, balsa or cedar) is glued into the center. At this stage, custom stringer and rocker configurations can also be implemented.
5. Final Touches: All the necessary information such as model, date, customer are sprayed onto the blank and it is good to go.

We want to point out that this is a very simplified process of making a PU surfboard blank. Highly skilled people are working in every step and just like your surfboard, a PU blank is still very much a hand made product that requires years of expertise and dedication to make it perfect.

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The tight cell structure that is created through this process lends itself perfectly to the shaping process as it allows shapers to work with very high attention to detail and realize meticulous design choices in foam. Furthermore it is largely responsible for the responsive feel we as surfers want from a board. The production process is also perfect to create different densities for surfboard foam, making it ideal for all wave conditions from ultra light performance surfing, or more heavy foams for traditional logging or tow in surfing.

Summary Polyurethane (PU) Foam:

We can summarize that PU foam’s popularity among shapers stems from its easy shaping and overall work process, while surfers appreciate the responsive feel and versatility it offers across different wave conditions. Additionally, its compatibility with both polyester and epoxy resins makes it highly adaptable in board construction and therefore the most versatile material to build surfboards.

What is EPS Foam, and How is it Made?

Expanded Polystyrene (EPS) foam is a lightweight material composed of small polystyrene beads expanded and fused together.It’s widely used for beginner boards and  some surfers prefer it in certain conditions  where weight is the most important consideration, for example in wave pool sessions or very glassy  conditions. As EPS foam is essentially made up of polystyrene beads and air it behaves unlike PU foam in water. Due to the material structure the transfer of energy from the wave through the board and the response of the surfer through their maneuver will evoke a different feeling when surfing. Furthermore EPS foam is less dense and therefore lighter resulting in more buoyancy. Buoyancy itself depends on the volume of the board and the density of the material relative to water, not just the material’s type. (EPS itself is not inherently more buoyant than PU foam; buoyancy is a result of the board's overall volume and density. However, because EPS foam is lighter and less dense, surfboards made with EPS tend to displace less water and "sit higher" on the surface, giving the impression of greater buoyancy). Combined with the overall structure of the material this creates the so called feeling of “chatter” in most everyday conditions where you have some wind and bump in the wave.The board feels more like planing over surfers and doesn’t have the same dampening effect like PU foam does.

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Simplified Production Process of EPS Foam Blanks:

1. Raw Material Expansion: Polystyrene beads are heated with steam, causing them to expand up to 50 times their original size.
2. Pre-Molding: The expanded beads are dried and placed into a mold that shapes the surfboard blank.
3. Fusion: Steam is applied again inside the mold to bond the beads into a single block of foam.
4. Cutting and Shaping: The cooled blank is trimmed and shaped for surfboard construction.

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Summary Expanded Polystyrene (EPS) Foam Blanks:

EPS foam can be lighter than PU foam which some surfers prefer in certain conditions. In general EPS can be recycled however the recycling process usually results in beads with lower mechanical properties and therefor in the production of products with lower value. Furthermore the bead structure makes it harder to shape and also results in absorption of water if the final board gets damaged.EPS foam works exclusively with epoxy resins, as polyester resin dissolves the foam.

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Conclusion: PU Foam, The Choice for Shaping the Future

While EPS foam has its place in surfboard construction for certain niche applications, PU foam clearly stands out as the superior material for both surfers and shapers. Its smooth shaping properties, versatility across density ranges, and compatibility with both polyester and epoxy resins make PU foam the preferred choice in the surf industry.

At Polyola, we’ve taken this trusted material to the next level by creating recycled PU blanks that deliver the performance surfers demand while significantly reducing their environmental impact. By crafting blanks made with 2/3 recycled materials and reducing CO₂ emissions by 73%, we’re setting a new standard for sustainable surfboard materials.

Choosing PU foam isn’t just about better performance—it’s about embracing a material that adapts to your needs and aligns with a commitment to protecting the planet. Whether you’re a shaper looking for precision or a surfer seeking durability and a reliable ride, PU foam remains the clear choice for shaping the future of surfing responsibly.

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