A PP honeycomb core is a lightweight structural core material made from polypropylene, formed into a repeating hexagonal or tubular cell structure. The geometry distributes compressive and shear loads across the panel surface, delivering high stiffness relative to weight. It is one of two core materials used in thermoplastic sandwich panels, alongside PP foam, and is selected when load-bearing performance is the primary requirement.
PP honeycomb sits at the higher end of the performance range within thermoplastic cores. Its closed-cell geometry resists moisture absorption and maintains structural integrity under repeated mechanical loading, which makes it particularly well suited to floor panels and scaffolding boards. The sections below answer the most common technical questions about how PP honeycomb works, what it can do, and where it performs best.
What makes PP honeycomb different from other core materials?
PP honeycomb differs from other core materials in its combination of high compressive strength, low weight, and full thermoplastic recyclability. The tubular or hexagonal cell geometry concentrates material only where it carries load, leaving the interior of each cell empty. This makes PP honeycomb significantly stiffer under point loads than foam cores of comparable weight, and far lighter than solid polymer or metal alternatives.
Compared to oriented PP foam, which is the other core type used in thermoplastic sandwich panels, PP honeycomb offers higher compressive strength and is better suited to applications where panels carry concentrated vertical loads, such as a forklift wheel on a truck floor or a worker standing on a scaffolding board. PP foam, by contrast, is more appropriate for wall cladding and other applications where compressive loads are not dominant.
The all-polypropylene composition also matters for durability and end-of-life handling. Because the core and the skin matrix share the same polymer family, the panel can be processed as a single material stream at end of life, which is relevant for European OEMs subject to recyclability requirements under the EU End-of-Life Vehicles Directive.
How is a PP honeycomb core manufactured?
PP honeycomb cores are produced by extruding polypropylene into tubes, then bonding those tubes together in a parallel array to form a continuous block. The block is then sliced to the required core thickness. The result is a grid of open tubes running perpendicular to the panel face, which is the orientation that gives the core its compressive load-bearing capacity.
The tube diameter determines the balance between cell wall density and open area. In Compoform’s floor and scaffolding panels, the PP honeycomb uses an 8 mm tube diameter, which provides a well-tested balance between compressive strength and overall panel weight. The core density is controlled by adjusting wall thickness and tube packing, with 140 kg/m³ used for floor panels and 120 kg/m³ for scaffolding applications where the load profile differs.
Once the core is produced, it is laminated with glass-fibre-reinforced thermoplastic skins in a continuous press process. The skins bond directly to the tube ends of the honeycomb, creating a mechanical and thermal bond that transfers loads between the skin and core without adhesive layers that could delaminate over time.
What are the mechanical properties of PP honeycomb?
PP honeycomb cores deliver high compressive strength and stiffness relative to their density, making them the preferred choice for load-bearing sandwich panel applications. The specific values depend on density, but the performance advantage over foam cores is consistent across the range.
Based on Compoform’s own testing to EN ISO 844, the 140 kg/m³ PP honeycomb used in floor panels achieves a compressive strength of approximately 3.6 MPa and a compressive modulus of around 123 MPa. The 120 kg/m³ variant used in scaffolding panels delivers lower compressive strength, appropriate for the different load distribution in that application. For comparison, the 60 kg/m³ PP foam used in wall panels achieves a compressive strength of around 0.75 MPa, which is sufficient for vertical cladding but not for flooring.
Water absorption across all PP honeycomb panel configurations remains below 1.5% (tested to ISO 62), which is important for panels exposed to wash-down cycles or outdoor conditions. All panels with durability testing pass a three-test battery: 2,000 hours of heat ageing at 80°C, UV ageing per ISO 4892-2, and 500 hours of alkaline ageing. The operating temperature range for finished panels is -40°C to +80°C, covering the full range of European transport and outdoor use conditions.
What applications is PP honeycomb core used for?
PP honeycomb core is used in applications where panels must carry significant compressive or point loads without deflecting. The two primary application areas in 2026 are commercial vehicle flooring and scaffolding boards, both of which demand structural performance that foam cores cannot reliably deliver.
In truck bodies and trailers, PP honeycomb floor panels replace plywood or steel decking. A 30 mm PP honeycomb sandwich floor panel is self-supporting across standard trailer bay widths, which means no aluminium subframe is required beneath it. Removing the subframe eliminates a production step for the body builder and reduces the total structural weight of the vehicle. For electric truck operators, that weight saving translates directly into extended battery range per charge, not just additional payload capacity. In 2026, EV fleet procurement teams routinely ask about structural weight as a range argument, and PP honeycomb panels are a direct answer to that question.
In scaffolding, a 10.5 mm Compoform PP honeycomb panel achieves EN 12811 load class 4 with no support underneath, based on Compoform’s own testing. This is a meaningful structural benchmark for scaffolding contractors who need to demonstrate compliance on site without adding intermediate supports.
Beyond these two primary markets, PP honeycomb panels are also used in cargo box construction, horse vans, and other specialist vehicle bodies where floor load requirements exceed what foam-core panels can provide.
How does PP honeycomb perform in sandwich panel construction?
In a sandwich panel, the PP honeycomb core acts as the structural web between two stiff face skins. The skins carry tensile and compressive bending stresses, while the core resists shear forces and keeps the skins separated at the designed distance. The wider the core, the greater the panel’s bending stiffness, without a proportional increase in weight.
The glass-fibre-reinforced thermoplastic skins bonded to PP honeycomb cores contain 66 to 67% glass fibre by content, tested to ASTM D5630. Skin architectures are selected based on the load direction the panel will experience. A 4-ply unidirectional skin is used on floor panels where loads are predominantly in one direction, while cross-ply and multi-ply configurations are used where biaxial strength is needed.
Panel dimensions can reach up to 13,500 mm × 2,900 mm in a single piece, which allows truck body builders and trailer manufacturers to cover large floor areas without joints. Joints in floor panels are a common source of moisture ingress and structural weakness, so the ability to produce oversized panels in a single continuous run is a practical advantage in vehicle construction.
Edge sealing and edge bending protect the honeycomb core from UV exposure and moisture at the panel perimeter. This is particularly relevant for scaffolding boards and truck floors that are regularly washed down or left exposed to weather.
Is PP honeycomb core recyclable?
Yes. PP honeycomb cores are fully recyclable because polypropylene is a thermoplastic that can be remelted and reprocessed. When the core and the skin matrix are both polypropylene-based, the entire panel can be processed as a single polymer stream at end of life, without the need to separate incompatible materials.
This matters commercially for European OEMs. The EU End-of-Life Vehicles Directive sets recyclability targets that apply to vehicle components, and procurement engineers at truck body builders and trailer manufacturers increasingly need to document the recyclability of the materials they specify. A fully thermoplastic sandwich panel with a PP honeycomb core satisfies that requirement in a way that multi-material panels with thermoset skins or mixed-material cores do not.
European sustainability reporting requirements under the CSRD are also pushing manufacturers to quantify and disclose the recyclability of their supply chain inputs. Specifying a fully thermoplastic panel simplifies that reporting and reduces the risk of future compliance issues as regulations tighten.
How Compoform Supports Your PP Honeycomb Panel Specification
We manufacture PP honeycomb sandwich panels for commercial vehicle floors and scaffolding boards from our production facilities in the Netherlands, with a semi-automatic line capable of producing panels up to 13,500 mm × 2,950 mm × 150 mm. Every panel is 100% European-made, which means consistent quality, reliable lead times, and no supply chain exposure to long-haul logistics disruption.
When you work with us, we do not simply ship panels to a drawing. We review your application, your assembly process, and your load requirements before confirming a panel configuration. That review covers:
- Core density selection — matching 120 or 140 kg/m³ honeycomb to your actual load class, not defaulting to the heaviest option
- Skin architecture — selecting 2-ply, 4-ply, or cross-ply glass-fibre skins based on the direction and magnitude of loads in your application
- Panel dimensions — cutting to your exact specification, including oversized single-piece floors that eliminate joints
- Edge treatment — advising on edge sealing or bending where the panel will be exposed to moisture or UV
- Subframe requirements — confirming whether a self-supporting configuration removes the need for an aluminium underframe in your build
Over a 15-year vehicle life, a composite floor eliminates two to three plywood replacement cycles. When you factor in panel cost, installation labour, and vehicle downtime for each replacement, the composite option is cheaper per year of service, even at a higher unit price. We can work through that calculation with you using your own vehicle volumes and maintenance cost data.
For scaffolding applications, we can provide the EN 12811 test data for our panels directly, which supports your compliance documentation without requiring you to commission independent testing.
If you are specifying a floor panel for a truck body or trailer, or evaluating PP honeycomb for a scaffolding board application, speak with our engineering team about your panel specification. We will review your design, flag any integration issues before production starts, and confirm the right configuration for your build, not just the closest standard product.