The maximum size of a thermoplastic sandwich panel is 13,500 mm × 2,950 mm × 150 mm, roughly 13.5 meters long, nearly 3 meters wide, and up to 150 mm thick. That is the production envelope we operate at Compoform, made possible by our 72-meter semi-automatic continuous production line in the Netherlands. Panel size limits vary by manufacturer and process, but for most commercial vehicle and scaffolding applications, the practical question is not whether a panel can be made large enough; it is how size interacts with structural performance and assembly requirements.
How big can a sandwich panel actually be manufactured?
In continuous thermoplastic production, sandwich panels can be manufactured up to approximately 13,500 mm in length and 2,950 mm in width, with thicknesses ranging from around 10 mm to 150 mm. These dimensions cover the vast majority of truck body, trailer, and scaffolding applications without any need for on-site joining or splicing.
The upper limit on panel size is set by the production line itself, specifically the width of the lamination press and the length of the conveyor system. Batch or press-based processes used by smaller manufacturers typically cap out at much shorter lengths, often 6,000 mm or less. Continuous production lines, by contrast, can produce panels in near-arbitrary lengths, with width being the more fixed constraint.
Thickness is a separate dimension governed by core material and skin build-up. For thermoplastic panels using PP-honeycomb or PP-foam cores, practical thicknesses run from 11 mm for lightweight scaffolding boards up to 30 mm or more for heavy-duty floor panels, and beyond that for structural applications requiring deep cross-sections.
What factors limit the maximum size of a sandwich panel?
The maximum size of a sandwich panel is limited by four main factors: production line geometry, core material behavior at scale, skin lamination uniformity, and handling and transport constraints. Each of these sets a practical ceiling independently of the others.
- Production line width: The lamination press width defines the maximum panel width. Panels wider than the press cannot be produced in a single pass, and joining two narrower panels introduces a seam that weakens the structure.
- Core material consistency: At very large formats, maintaining uniform core density and bond quality across the full panel area becomes more demanding. PP-foam cores are available in densities from 40 to 140 kg/m³, and achieving consistent lamination across a 13-meter panel requires precise process control throughout the run.
- Skin lamination uniformity: Glass-fiber skins must bond evenly to the core across the entire panel surface. Any variation in temperature, pressure, or feed speed during continuous lamination can create localized weak zones, which is why semi-automatic production lines with tight process monitoring are preferred for large-format panels.
- Transport and handling: A panel measuring 13,500 mm × 2,950 mm requires specialized transport and lifting equipment. For many customers, the practical maximum is determined not by what can be produced, but by what can be moved through their assembly facility and loaded onto a vehicle.
For most European truck body builders and trailer manufacturers, panels in the range of 6,000 mm to 13,500 mm long and up to 2,500 mm wide represent the working sweet spot, large enough to minimize joints in the finished structure, manageable enough to handle with standard workshop equipment.
Does panel size affect structural performance?
Panel size does not directly reduce structural performance, but it does change how loads are distributed and how the panel must be supported. A larger panel spanning a greater unsupported distance will deflect more under the same load, so the structural specification must account for span, not just panel dimensions.
Thickness plays a larger role in load-bearing performance than length or width. A 30 mm floor panel with a 140 kg/m³ PP-honeycomb core sustains substantially higher absolute loads than a 15 mm panel of the same construction; the deeper cross-section increases bending resistance significantly. This is why floor panels for truck bodies and trailers are typically specified at 15 mm to 30 mm, while wall panels for the same vehicles can be thinner.
One practical advantage of large-format thermoplastic sandwich panels is that they can be self-supporting across wide spans. A 30 mm PP-honeycomb floor panel, for example, does not require an aluminium subframe underneath; the panel itself carries the load. For truck body builders, this removes a production step and reduces the total weight of the floor assembly, which matters both for payload capacity and, increasingly, for battery range in electric trucks and vans.
Lighter body structures extend battery range in electric trucks and vans. Every kilogram of structural dead weight reduces range per charge, making weight reduction a range argument, not just a payload argument. This is a standard procurement question from EV fleet buyers in 2026, and large-format composite panels that eliminate subframes contribute directly to that calculation.
Can sandwich panels be made to custom dimensions?
Yes. Thermoplastic sandwich panels are available in custom dimensions cut to your exact specification. The continuous production process produces panels in large master formats, which are then cut to the precise length, width, and profile required for your application, including CNC routing for cutouts, notches, and edge profiles.
Custom dimensioning is particularly valuable for truck body builders and trailer manufacturers, where panel dimensions must match body geometry precisely. A panel cut to the exact internal length of a cargo box eliminates on-site trimming, reduces waste, and ensures consistent fit across a production run. This is not a bespoke service reserved for large orders; it is standard practice for mid-volume OEM supply.
Edge treatment is an important part of custom panel production. Cut edges expose the core material, which must be sealed to protect against moisture ingress and UV degradation. Edge sealing and edge bending are available as part of the panel finishing process, which is relevant for scaffolding boards and truck floors that are regularly washed down or exposed to weather.
What is the maximum size for sandwich panels used in trucks and trailers?
For truck body and trailer applications, sandwich panels are typically produced up to 13,500 mm in length and 2,950 mm in width, dimensions that cover the full floor or wall of a standard European semi-trailer in a single panel or a small number of panels with minimal joints. Thickness for floor panels typically runs from 15 mm to 30 mm depending on load class and span.
The ability to produce panels at this scale matters commercially. A trailer floor built from fewer, larger panels has fewer joints, which means fewer potential weak points and a faster assembly process. For a truck body builder producing at volume, reducing the number of floor panels per unit from four to two, by using longer, wider panels, can meaningfully reduce assembly time per vehicle.
Thermoplastic composite floors also outlast plywood in heavy transport applications. Industry experience with composite truck floors points to service lives of 12 years or more, compared to 3 to 5 years for plywood. Over a 15-year vehicle life, that eliminates two to three replacement cycles. Once 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.
How Compoform Helps with Sandwich Panel Sizing
We produce thermoplastic sandwich panels up to 13,500 mm × 2,950 mm × 150 mm on our 72-meter semi-automatic production line in the Netherlands, one of the largest production envelopes available from a European manufacturer. All panels are 100% European-made, at our facilities in Beek and Ospel.
For truck body builders, trailer manufacturers, and scaffolding companies, we offer:
- Custom panel dimensions cut to your exact specification, including CNC routing for cutouts and edge profiles
- PP-honeycomb and PP-foam core options in multiple densities, matched to your load requirements and target weight
- Edge sealing and edge bending to protect cut edges from moisture and UV in demanding operating environments
- Self-supporting floor panels that eliminate the need for an aluminium subframe, reducing weight and simplifying your assembly process
- Engineering review of your panel configuration before production; we check span, load class, edge conditions, and assembly method, and flag issues before they reach your production line
We work with you as an application partner, not a panel supplier. That means reviewing your design, optimising the panel specification for your assembly process, and staying involved through integration and iteration, not just the initial order. If you are specifying panels for a truck body or trailer floor and want to confirm the right dimensions and construction for your application, get in touch with our engineering team.