What is a PP honeycomb core?

Compoform · 25 Jul 2026

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 and delivers high stiffness relative to weight. It is one of the two core materials used in thermoplastic sandwich panels, alongside PP foam, and is chosen when load-bearing capacity is the primary requirement.

PP honeycomb sits at the higher end of the performance range among thermoplastic cores. Its closed-cell geometry resists moisture absorption and maintains structural integrity under repeated mechanical loading, making it particularly well suited to floor panels and scaffold components. The sections below answer the most frequently asked 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 stands apart from other core materials through 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 considerably stiffer under point loads than foam cores of comparable weight, and much lighter than solid polymer or metal alternatives.

Compared with oriented PP foam, 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 loading floor or a worker standing on a scaffold component. PP foam, by contrast, is better suited to wall cladding and other applications where compressive loads are not dominant.

The all-polypropylene composition also matters for sustainability and end-of-life processing. Because the core and the skin matrix belong to 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 produced?

PP honeycomb cores are produced by extruding polypropylene into tubes and then joining these tubes in a parallel arrangement to form a continuous block. The block is then cut to the required core thickness. The result is a grid of open tubes running perpendicular to the panel surface, the orientation that gives the core its load-bearing capacity under compressive loading.

Tube diameter determines the balance between cell wall density and open area. In Compoform’s floor and scaffold panels, the PP honeycomb uses an 8 mm tube diameter, which offers a well-tested balance between compressive strength and total panel weight. Core density is controlled by adjusting wall thickness and tube packing, with 140 kg/m³ used for floor panels and 120 kg/m³ for scaffold applications where the load profile differs.

Once the core is produced, it is laminated with glass-fibre-reinforced thermoplastic skins in a continuous pressing process. The skins bond directly to the tube ends of the honeycomb, creating a mechanical and thermal bond that transfers loads between 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 gap compared with foam cores is consistent across the entire 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 scaffold panels delivers a lower compressive strength, in line with the different load distribution in that application. By 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 floors.

Moisture absorption across all PP honeycomb panel configurations remains below 1.5% (tested to ISO 62), which matters for panels exposed to cleaning 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 to 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.

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What 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 floors and scaffold components, both of which require structural performance that foam cores cannot reliably deliver.

In truck bodies and trailers, PP honeycomb floor panels replace plywood or steel floor plates. A 30 mm PP honeycomb sandwich floor panel is self-supporting across standard trailer width, meaning no aluminium subframe is needed beneath it. Omitting the subframe eliminates a production step for the body builder and reduces the overall structural weight of the vehicle. For operators of electric trucks, that weight saving translates directly into greater battery range per charge, not just additional payload capacity. In 2026, procurement teams for EV fleets 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 reaches load class 4 under EN 12811 without support beneath it, based on Compoform’s own testing. This is a meaningful structural benchmark for scaffold builders who need to demonstrate compliance on site without adding intermediate support points.

Beyond these two primary markets, PP honeycomb panels are also used in the construction of box bodies, horse trailers and other specialised vehicle bodies where floor load requirements exceed the capabilities of foam core panels.

How does PP honeycomb perform in sandwich panel construction?

In a sandwich panel, the PP honeycomb core acts as the structural spacer between two rigid outer skins. The skins carry tensile and compressive bending stresses, while the core resists shear forces and holds the skins at the designed distance from each other. The thicker the core, the greater the bending stiffness of the panel, without a proportional increase in weight.

The glass-fibre-reinforced thermoplastic skins bonded to PP honeycomb cores contain 66 to 67% glass fibre by weight, tested to ASTM D5630. Skin architectures are selected based on the load direction the panel will experience. A 4-layer unidirectional skin is used on floor panels where loads are predominantly in one direction, while cross-ply and multi-layer configurations are used where biaxial strength is required.

Panel dimensions can reach 13,500 mm × 2,900 mm in a single piece, allowing truck body builders and trailer manufacturers to cover large floor areas without seams. Seams in floor panels are a common source of moisture ingress and structural weakness, so the ability to produce oversized panels in a single continuous production run is a practical advantage in vehicle construction.

Edge sealing and edge folding protect the honeycomb core from UV exposure and moisture at the panel edge. This is particularly relevant for scaffold components and truck loading floors that are regularly washed down or exposed to the 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 both the core and the skin matrix are based on polypropylene, the entire panel can be processed as a single polymer stream at end of life, without having 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 meets 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 chains. Specifying a fully thermoplastic panel simplifies that reporting and reduces the risk of future compliance problems as regulations tighten.

How Compoform supports your PP honeycomb panel specification

We produce PP honeycomb sandwich panels for commercial vehicle floors and scaffold components at our production facilities in the Netherlands, using a semi-automatic line that can produce panels up to 13,500 mm × 2,950 mm × 150 mm. Every panel is 100% European-made, which ensures consistent quality, reliable lead times and no exposure to supply chain disruptions caused by long-distance logistics.

When you work with us, we do not simply ship panels based on 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, without defaulting to the heaviest option
Skin architecture — selecting 2-layer, 4-layer or cross-ply glass fibre skins based on the direction and magnitude of the loads in your application
Panel dimensions — cut to your exact specification, including oversized one-piece floors that eliminate seams
Edge treatment — advice on edge sealing or folding where the panel is exposed to moisture or UV
Subframe requirements — confirming whether a self-supporting configuration removes the need for an aluminium subframe in your construction

Over a vehicle lifetime of 15 years, a composite floor eliminates two to three plywood replacement cycles. When you factor in the 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 costs.

For scaffold applications, we can supply the EN 12811 test data for our panels directly, which supports your compliance documentation without you having to commission independent testing.

If you are specifying a floor panel for a truck body or trailer, or evaluating PP honeycomb for a scaffold component application, discuss your panel specification with our engineering team. We review your design, flag any integration issues before production begins and confirm the right configuration for your construction, not just the nearest standard product.