Sandwich panels are used in truck body building because they deliver a high strength-to-weight ratio that steel and plywood cannot match. A composite sandwich structure combines rigid outer skins with a lightweight core, producing a panel that carries structural loads while adding far less dead weight to the vehicle. The questions below unpack the specific advantages, panel types, attachment methods, and regulations that matter most to truck body builders.
This article covers the broader sandwich panel market. Compoform’s range is limited to PP honeycomb and PET foam cores for commercial vehicles and scaffolding.
What advantages do sandwich panels offer over steel and aluminum in truck bodies?
Sandwich panels outperform steel and aluminum in truck body applications by delivering comparable structural performance at a fraction of the weight. A glass-fibre reinforced thermoplastic sandwich panel typically weighs significantly less than an equivalent steel panel, and unlike aluminum, composite panels resist corrosion without surface treatment, reduce thermal bridging, and can be produced in single-piece sections that eliminate welded joints.
The practical advantages for truck body builders include:
- Weight reduction: Replacing steel side walls and floors with composite sandwich panels removes meaningful kilograms from the body structure, directly increasing the payload a vehicle can legally carry.
- Corrosion resistance: Thermoplastic skins do not rust. Truck bodies operating in wet or salted environments maintain their structural integrity without the surface treatments steel requires.
- Thermal insulation: The foam or honeycomb core provides a natural thermal break, reducing heat transfer through the body walls. This matters for temperature-sensitive cargo and reduces the load on refrigeration systems.
- Dimensional stability: Composite panels do not warp, swell, or degrade the way plywood does when exposed to repeated washing and moisture cycles.
- Large-format production: Sandwich panels can be manufactured in single sheets up to 13,500 mm long, reducing the number of joints in a body and simplifying assembly.
Aluminum offers a weight advantage over steel but still corrodes in certain environments, requires specialist welding, and cannot match the insulation properties of a foam-core composite. For truck body builders weighing total cost of ownership rather than unit material cost, composite sandwich panels consistently deliver a stronger long-term case. You can explore composite panel applications across transport sectors to see how different body types are specified.
How do sandwich panels affect payload capacity and fuel efficiency?
Every kilogram removed from the truck body structure is a kilogram that can be converted into revenue-generating cargo. Sandwich panels reduce body dead weight compared to steel or plywood equivalents, which directly increases the legal payload a vehicle can carry under European gross vehicle weight regulations. For high-frequency distribution operations, this weight saving compounds across every trip and every vehicle in a fleet.
Fuel efficiency follows the same logic. A lighter body requires less engine output to maintain speed and acceleration, which reduces fuel consumption per kilometre. For diesel fleets, this translates into measurable operating cost reductions over a vehicle’s working life.
For electric trucks and vans, the weight argument becomes even more direct. Lighter body structures extend battery range per charge. Every kilogram of structural dead weight reduces the distance an electric truck can travel before needing to recharge. In 2026, this is a standard procurement question from EV fleet buyers: how much does the body structure weigh, and what does that mean for range? Weight reduction is no longer just a payload argument. It is a range argument, and composite sandwich panels address both simultaneously.
What types of sandwich panels are used in truck body building?
Truck body builders use sandwich panels with different core materials and skin architectures depending on the application within the body. The main distinction is between wall panels and floor panels, which face very different load conditions and surface requirements.
Wall and side panels
Side walls and roof panels carry lower structural loads than floors. They need to be lightweight, weather-resistant, and dimensionally stable. Glass-fibre reinforced thermoplastic skins laminated onto a PP foam core are well suited here. A cross-ply skin architecture, where fibres run at 0° and 90° in alternating layers, equalises mechanical properties in both directions, making the panel suitable for installation in either orientation. White PET-film surface finishes provide a clean, finished appearance without additional painting.
Floor panels
Truck floors carry concentrated point loads from pallet trucks, forklifts, and heavy cargo. Floor panels therefore use denser, stiffer cores. PP honeycomb cores at higher densities deliver substantially higher bending and compressive performance than foam cores of similar thickness. A 4-ply glass-fibre skin with a black anti-skid surface finish is standard for floor applications, providing grip and durability under repeated loading. A 30 mm PP honeycomb floor panel, for example, is self-supporting across standard truck body widths without requiring an aluminum subframe beneath it. This removes a production step and reduces both material cost and assembly time for the body builder.
How are sandwich panels attached to truck body frames?
Sandwich panels in truck bodies are attached using a combination of mechanical fasteners, adhesive bonding, and extruded aluminum or thermoplastic profiles, depending on the body design and the loads the joint must carry. The correct attachment method depends on the panel thickness, core type, and whether the joint needs to be removable for maintenance.
Common attachment approaches include:
- Aluminum extrusion profiles: Panels slot into or clip onto extruded profiles that run along the frame rails and corner posts. This is the most common method for side walls and provides a clean, sealed joint.
- Structural adhesive bonding: Two-component polyurethane or epoxy adhesives bond panels directly to the frame structure. Adhesive bonding distributes load evenly across the joint face and avoids stress concentrations around fastener holes.
- Mechanical fasteners: Rivets or bolts through the panel face are used where panels need to be removable or where adhesive bonding is not practical. Fasteners must be sized to avoid crushing the core, and washers or backing plates are used to spread the load.
- Combined adhesive and mechanical fixing: Many body builders use adhesive as the primary load path and mechanical fasteners as a secondary retention method during cure and for long-term security.
Edge sealing is important regardless of attachment method. Exposed core edges are vulnerable to moisture ingress, particularly on floor panels that are washed down regularly. Sealed or banded edges protect the core and extend panel service life significantly.
Are sandwich panels strong enough for heavy-duty transport applications?
Yes. Properly specified sandwich panels meet the structural demands of heavy-duty truck body applications, including floor loading from pallet trucks and forklifts, side wall impact resistance, and roof loading from cargo stacked against the body. The key is matching the panel specification to the load case, which means selecting the right core density, skin architecture, and panel thickness for each position in the body.
Thermoplastic sandwich panels with glass-fibre reinforced skins achieve bending performance that is tested and documented to ISO 14125. Floor panels using PP honeycomb cores at 140 kg/m³ with 4-ply skins sustain high concentrated loads in tested geometries. Compoform’s own test data shows a 30 mm floor panel sustaining an average maximum load of 5,647 N in the tested configuration, compared to 3,240 N for a 15 mm variant. These are Compoform’s internal test results and should be confirmed against the specific load requirements of your application before specifying.
Thermoplastic panels also offer a meaningful durability advantage over plywood. In heavy transport applications, composite floors typically last three to four times longer than plywood equivalents. Over a 15-year vehicle life, that eliminates two to three plywood replacement cycles. When you account for panel cost, installation labour, and vehicle downtime during replacement, the composite floor is cheaper per year of service even at a higher unit price.
Continuous fibre-reinforced thermoplastic skins also provide impact resistance that matters in loading dock environments, where panels are regularly struck by pallet truck forks and cargo edges.
What regulations affect sandwich panel use in European truck bodies?
European truck body builders working with sandwich panels need to be aware of regulations covering vehicle weight, fire performance, and end-of-life recyclability. These are not optional considerations. They affect material selection, body approval, and increasingly, procurement decisions from fleet operators subject to their own compliance obligations.
- Gross vehicle weight and axle load limits: EU regulations set maximum permissible weights for vehicles operating on public roads. Body weight directly affects how much payload a vehicle can legally carry, which is why lightweight panel construction is not just a performance preference but a regulatory and commercial necessity.
- Fire performance (EN 13501-1): Panels used in enclosed cargo bodies may need to meet fire classification requirements depending on the cargo type and operating environment. Thermoplastic panels should be specified with fire performance data that references EN 13501-1 classifications.
- End-of-life vehicle (ELV) Directive: The EU ELV Directive requires that a high proportion of vehicle materials be recoverable or recyclable at end of life. Thermoplastic sandwich panels offer a recyclability advantage over thermoset composites because the thermoplastic matrix can be reprocessed. For OEMs subject to CSRD sustainability reporting obligations, this is increasingly a procurement filter, not just a preference.
- ADR regulations: Vehicles carrying hazardous goods are subject to ADR requirements that may specify material properties for the cargo body. Body builders working in this segment should confirm panel fire and chemical resistance properties against the relevant ADR class requirements.
How Compoform Helps Truck Body Builders Specify the Right Panel
We work with truck body builders and trailer manufacturers across Europe to specify sandwich panels that match the structural, dimensional, and regulatory requirements of their specific body designs. This is not a catalogue selection process. We review your load cases, assembly method, and operating environment before recommending a panel configuration.
What we bring to that process:
- Custom dimensions: Panels are available in custom dimensions cut to your exact specification, up to 13,500 mm × 2,950 mm. Single-piece side walls and floors reduce joint count and simplify assembly.
- Application-matched core selection: We offer PP honeycomb and PET foam cores across a range of densities. Floor panels, wall panels, and roof panels each have different requirements, and we specify accordingly rather than applying a single configuration across the body.
- Self-supporting floor panels: Our 30 mm PP honeycomb floor panels are self-supporting across standard truck body widths, removing the need for an aluminum subframe and reducing both material cost and assembly steps.
- Documented performance data: We provide technical data sheets and test reports referenced to European standards, giving your engineering team the documentation needed for body approval and customer sign-off.
- Edge sealing and surface finish options: Anti-skid floor surfaces, white PET-film wall finishes, and sealed edges are available as part of the panel specification, not as aftermarket additions.
- Long-term partnership: We support you through integration, address issues that arise during production runs, and work with you on design iterations as your body programme evolves.
If you are evaluating composite panels for a truck body programme, bring us your design early. We will review the load requirements, flag any specification risks before production, and help you build a body that performs better and costs less to operate over its full service life. See how our panels perform in truck body applications and get in touch with our panel specialists to start the conversation.