What is the maximum size of a sandwich panel?

Compoform · 26 Jul 2026

The maximum size of a thermoplastic sandwich panel is 13,500 mm × 2,950 mm × 150 mm, roughly 13.5 metres long, almost 3 metres wide and up to 150 mm thick. That is the production envelope we work within at Compoform, made possible by our 72-metre semi-automatic continuous production line in the Netherlands. The maximum panel size varies by manufacturer and production process, but for most applications in commercial vehicles and scaffolding, the practical question is not whether a panel can be made large enough, but how the size relates to structural performance and installation requirements.

How large can a sandwich panel actually be produced?

With 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 applications for truck bodies, trailers and scaffolding without the need for on-site joining or splicing.

The upper limit of panel size is determined by the production line itself, in particular the width of the laminating press and the length of the conveyor system. Batch or press-based processes used by smaller manufacturers typically reach a maximum of much shorter lengths, often 6,000 mm or less. Continuous production lines, by contrast, can produce panels in virtually any length, with width being the more fixed limiting factor.

Thickness is a separate dimension, determined by the core material and the skin layer build-up. For thermoplastic panels with PP honeycomb or PP foam cores, practical thicknesses range from 11 mm for lightweight scaffolding floors to 30 mm or more for heavily loaded floor panels, and beyond that for structural applications where deep cross-sections are required.

What factors limit the maximum size of a sandwich panel?

The maximum size of a sandwich panel is limited by four main factors: the geometry of the production line, the behaviour of the core material at large scale, the uniformity of the skin lamination, and handling and transport constraints. Each of these factors sets a practical ceiling independently of the others.

Production line width: The width of the laminating press determines 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 sizes, it becomes increasingly demanding to maintain uniform core density and bond quality across the entire panel surface. PP foam cores are available in densities from 40 to 140 kg/m³, and achieving consistent lamination over a 13-metre panel requires precise process control throughout the entire production run.
Skin lamination uniformity: Glass fibre skins must bond evenly to the core across the entire panel surface. Any variation in temperature, pressure or feed speed during continuous lamination can cause localised weak zones. This is why semi-automatic production lines with tight process monitoring are preferred for large-format panels.
Transport and handling: A panel of 13,500 mm × 2,950 mm requires specialised transport and lifting equipment. For many customers, the practical maximum is determined not by what can be produced, but by what their assembly facility can move and load 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 practical ideal size: large enough to minimise joints in the finished structure, and 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 needs to be supported. A larger panel spanning a greater unsupported distance will deflect more under the same load, so the structural specification must account for the span and not only the panel dimensions.

Thickness plays a bigger role in load-bearing capacity than length or width. A 30 mm floor panel with a 140 kg/m³ PP honeycomb core can carry considerably higher absolute loads than a 15 mm panel of the same construction; the deeper cross-section significantly increases bending resistance. 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.

A practical advantage of large-format thermoplastic sandwich panels is that they can be self-supporting over wide spans. A 30 mm PP honeycomb panel, for example, does not need an aluminium subframe beneath it; the panel itself carries the load. For truck body builders, this eliminates a production step and reduces the overall weight of the floor structure, which matters both for payload capacity and, increasingly, for the battery range of electric trucks and vans.

Lighter body structures increase the battery range of electric trucks and vans. Every kilogram of structural dead weight reduces the range per charge, which makes weight reduction a range argument and not only a payload argument. This is a standard purchasing question for EV fleet buyers in 2026, and large-format composite panels that eliminate subframes contribute directly to that calculation.

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Can sandwich panels be made to measure?

Yes. Thermoplastic sandwich panels are available in custom dimensions cut exactly to your specification. The continuous production process produces panels in large master sizes, which are then cut to the exact length, width and profile your application requires, including CNC milling for cut-outs, notches and edge profiles.

Custom sizing is particularly valuable for truck body builders and trailer manufacturers, where panel dimensions must match the body geometry precisely. A panel cut to the exact internal length of a cargo area eliminates on-site trimming, reduces waste and ensures a consistent fit across an entire production run. This is not a bespoke service reserved for large orders; it is standard practice for mid-sized OEM supplies.

Edge finishing is an important part of custom panel production. Cut edges expose the core material, which must be sealed to prevent moisture ingress and UV degradation. Edge sealing and edge bending are available as part of the panel finishing process, which is relevant for scaffolding floors and truck cargo floors that are regularly washed down or exposed to the weather.

What is the maximum size of sandwich panels 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 entire floor or wall of a standard European semi-trailer in a single panel or a small number of panels with minimal joints. The thickness for floor panels typically ranges from 15 mm to 30 mm, depending on the load class and the span.

The ability to produce panels at this scale is commercially significant. 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 noticeably shorten assembly time per vehicle.

Thermoplastic composite floors also last longer than plywood in heavy transport use. Practical experience with composite truck cargo floors points to a service life of 12 years or more, compared with 3 to 5 years for plywood. Over a vehicle lifetime of 15 years, that eliminates two to three replacement cycles. When you factor in panel costs, installation labour and vehicle downtime during replacement, the composite floor is cheaper per year of use, even at a higher unit price.

How does Compoform help with sandwich panel sizing?

We produce thermoplastic sandwich panels up to 13,500 mm × 2,950 mm × 150 mm on our 72-metre 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 sites in Beek and Ospel.

For truck body builders, trailer manufacturers and scaffolding companies, we offer:

Custom-sized panels cut to your exact specification, including CNC milling for cut-outs 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 against moisture and UV in demanding operating environments
Self-supporting floor panels that eliminate the need for an aluminium subframe, reduce weight and simplify your assembly process
Technical review of your panel layout before production; we check span, load class, edge conditions and mounting method, and flag issues before they reach your production line

We work with you as an application partner, not as a panel supplier. That means we review your design, optimise the panel specification for your assembly process and stay involved throughout integration and iteration — not only at 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, contact our engineering team.