Sandwich panels perform well in refrigerated vehicle bodies because their layered construction combines structural strength with built-in thermal resistance. A glass-fibre-reinforced thermoplastic skin bonded to a low-density core creates a panel that is rigid, lightweight, and resistant to moisture ingress, three properties that refrigerated body builders need simultaneously. The questions below unpack the specific performance factors that matter most when specifying panels for cold chain applications.
What makes sandwich panels suitable for refrigerated vehicle bodies?
Sandwich panels are suitable for refrigerated vehicle bodies because they combine structural load-bearing capacity, thermal insulation, and low weight in a single panel, properties that are difficult to achieve together with metal or timber construction. The sandwich structure places strong, stiff skins on the outer faces of a lightweight core, creating a panel that resists bending under load while the core limits heat transfer between the inside and outside of the body.
In a refrigerated body, the wall, floor, and roof panels must do several things at once. They must hold their shape under the mechanical stresses of loading, road vibration, and forklift contact. They must resist moisture penetration, because condensation and water ingress degrade insulation performance over time. And they must keep the thermal envelope intact across a vehicle life that typically spans ten to fifteen years.
Thermoplastic sandwich panels address all three demands. The glass-fibre-reinforced skins resist impact and abrasion, while the closed-cell or honeycomb core limits thermal conductivity. Because thermoplastic materials do not absorb water, the insulation value of the panel does not degrade the way it does in panels that use hygroscopic core materials. For refrigerated body builders, this means the vehicle maintains its temperature performance throughout its service life rather than declining as the core absorbs moisture.
How do sandwich panels compare to traditional insulated metal panels in reefer bodies?
Sandwich panels are significantly lighter than insulated metal panels of equivalent structural performance, and they do not corrode. Traditional insulated metal panels use steel or aluminium skins bonded to a foam core, which provides insulation but adds considerable dead weight. Composite sandwich panels with thermoplastic skins achieve comparable or superior stiffness at a fraction of the weight, which directly increases the payload a refrigerated vehicle can carry.
The weight difference has become a more prominent procurement argument in 2026 as fleet operators transition to electric refrigerated trucks and vans. Lighter body structures extend battery range in electric vehicles. Every kilogram of structural dead weight reduces range per charge, so weight reduction is now a range argument as well as a payload argument. EV fleet buyers increasingly ask about body weight as a standard part of the procurement process, and composite panels give body builders a concrete answer.
Metal panels also corrode at joints, fastener points, and areas where the surface coating is damaged. Thermoplastic composite panels do not rust, and their resistance to chemical cleaning agents makes them better suited to the wash-down cycles that refrigerated bodies undergo regularly. Over a fifteen-year vehicle life, the maintenance cost difference between metal and composite panels is material, even before accounting for the weight savings.
What core materials are used in sandwich panels for refrigerated vehicles?
The core materials used in sandwich panels for refrigerated vehicle bodies vary across the broader market, but the properties that matter for cold chain applications are low thermal conductivity, moisture resistance, and sufficient compressive strength to handle floor loads and wall impacts. This article covers the broader sandwich panel market. Our own range is limited to PP honeycomb and PET foam cores for commercial vehicles and scaffolding.
Across the market, common core types include:
- PP honeycomb: A polypropylene honeycomb structure that is very light, moisture-resistant, and dimensionally stable. It offers high compressive strength relative to its weight, making it well suited to floor panels in refrigerated bodies where forklift and pallet loads are concentrated.
- PET foam: A closed-cell polyethylene terephthalate foam that provides good thermal insulation, low moisture absorption, and consistent mechanical properties across a range of densities. PET foam cores can be specified at different densities to balance insulation performance against structural requirements.
Both PP honeycomb and PET foam cores are thermoplastic, which means the panels are fully recyclable at end of life. This is relevant for European body builders and fleet operators subject to the EU End-of-Life Vehicles Directive, where recyclability is a compliance requirement rather than a preference.
Core density is a key specification variable. Higher-density cores deliver greater compressive and shear strength but add weight. For refrigerated body walls, a lower-density core is often sufficient. For floors that must support heavy pallet loads, a higher-density core or a PP honeycomb configuration is the more appropriate choice.
How does panel thickness affect insulation performance in cold chain vehicles?
Greater panel thickness improves thermal insulation in refrigerated vehicle bodies because it increases the distance heat must travel through the core material. For a given core material, doubling the thickness roughly halves the rate of heat transfer through the panel. Body builders therefore balance the insulation benefit of thicker panels against the weight and internal volume they consume.
In practice, wall panel thickness in refrigerated bodies typically ranges from around 60 mm to 100 mm or more, depending on the temperature regime the vehicle must maintain. Deep-frozen transport requires thicker panels than chilled distribution, because the temperature differential between the cargo space and the external environment is much larger. The thermal conductivity of the core material, measured in accordance with EN 12667, determines how much thickness is needed to achieve a target U-value for the body.
Floor panels present a different trade-off. The floor must carry concentrated loads from forklifts and pallets, so the core must be stiffer and denser than a wall panel core. This means the floor panel may use a PP honeycomb core at higher density, which provides the compressive strength needed without requiring excessive thickness. The result is a floor that is structurally self-supporting without an aluminium subframe, which removes a production step and reduces the overall body weight.
Roof panels sit between walls and floors in terms of load requirements. They must resist snow loads and the occasional foot traffic during maintenance, but they do not carry the concentrated point loads that floors do. A mid-density foam core at moderate thickness is typically the right specification for refrigerated body roofs.
What are the hygiene and cleanability requirements for refrigerated body panels?
Refrigerated vehicle body panels must withstand repeated high-pressure wash-downs with water and cleaning agents without degrading, absorbing moisture, or developing surface defects that harbour bacteria. Regulatory requirements for food transport in Europe specify that interior surfaces must be smooth, non-absorbent, and resistant to the cleaning chemicals used in food-grade sanitation programmes.
Thermoplastic composite panels meet these requirements well. The glass-fibre-reinforced thermoplastic skins are non-porous, so they do not absorb water or cleaning agents. A white PET-film surface finish provides a smooth, cleanable surface with controlled colour properties. Panels with this finish have demonstrated UV resistance exceeding 22,000 hours in testing, which is relevant for exterior surfaces exposed to sunlight over the vehicle’s service life.
Edge sealing is an important detail that body builders should not overlook. Even if the panel faces are impermeable, an unsealed edge exposes the core to moisture ingress at joints, fastener holes, and cut-outs. Proper edge sealing and edge bending protect the core from water penetration during wash-downs, which is particularly important for floor panels that are regularly exposed to standing water and cleaning fluids.
The anti-skid surface finish available on floor panels adds a further hygiene consideration. The textured surface must be cleanable without trapping debris in the pattern. A moulded-in anti-skid finish, rather than an applied coating, avoids the risk of the surface layer peeling or lifting over time, which would create areas that are difficult to clean and could compromise food safety compliance.
When should a vehicle body builder switch from metal to composite sandwich panels?
A vehicle body builder should switch from metal to composite sandwich panels when the combined cost of dead weight, maintenance, and panel replacement over the vehicle’s life exceeds the higher unit cost of composite panels. For refrigerated bodies, this crossover point arrives earlier than many builders expect, because metal panels corrode, require repainting, and add weight that reduces payload or range on every trip the vehicle makes.
The most straightforward trigger is payload pressure. If a refrigerated body built with metal panels is close to the legal gross vehicle weight limit, switching to composite panels creates usable payload capacity without changing the vehicle specification. For a fleet operator running hundreds of vehicles, the revenue impact of additional payload per trip is significant over a multi-year contract.
The EV transition is accelerating this decision for many body builders in 2026. Electric refrigerated trucks have a fixed battery capacity, and every kilogram of structural dead weight reduces the range available for delivery routes. Fleet operators specifying new electric vehicles are asking body builders directly about panel weight, and composite panels give body builders a competitive answer that metal construction cannot match.
A further trigger is maintenance cost. Thermoplastic composite panels last significantly longer than metal panels in refrigerated body applications, and they do not require the repainting and corrosion treatment that metal demands. Over a fifteen-year vehicle life, eliminating two or three maintenance interventions represents a concrete cost saving that justifies the higher panel price at the point of purchase.
How We Help Refrigerated Body Builders Specify the Right Panel
We work with truck body builders and trailer manufacturers to specify panel configurations that match the exact demands of their refrigerated body designs. Rather than offering a standard catalogue, we review your body design, temperature regime, load requirements, and assembly process before recommending a panel specification. This means you get a panel that performs correctly in your application from the first production run, not after a series of costly iterations.
For refrigerated body applications, we can help with:
- Core selection and density: Matching PP honeycomb or PET foam core density to your floor load requirements and wall insulation targets
- Panel thickness specification: Calculating the thickness needed to achieve your target thermal performance for the temperature regime your vehicle must maintain
- Surface finish selection: Specifying white PET-film or anti-skid finishes appropriate for interior walls and floors in food-grade transport
- Custom dimensions: Producing panels up to 13,500 mm x 2,950 mm in a single piece, reducing the number of joints in the body and the associated sealing work
- Edge treatment: Advising on edge sealing and edge bending to protect the core at cut-outs, joints, and fastener positions
We also flag integration issues before production begins. If your assembly process involves a fastening method or adhesive system that is not compatible with the panel specification, we identify that at the design review stage rather than after panels are delivered. This is the difference between a panel supplier and an application partner.
If you are evaluating composite panels for refrigerated body applications, speak with our engineering team about your specific body design and operating requirements. We will review your application and recommend a panel configuration that meets your structural, thermal, and hygiene requirements while giving you a clear TCO argument to present to your customers.
If you are ready to discuss your requirements in detail, contact our engineering team directly to arrange a review of your body design and panel specification.