For most van conversion floors, a 15 mm sandwich panel is the standard starting point, while a 30 mm panel suits heavier-duty builds where point loads are higher or subframe support is reduced. The right thickness depends on how the van will be used, what loads the floor must carry, and whether you want the panel to be fully self-supporting. The sections below work through the key decisions that determine which specification fits your build.
What thickness options are available for sandwich panel floors?
Sandwich panel floors for van conversions are most commonly available in 15 mm and 30 mm configurations, both using a PP-honeycomb core bonded between glass-fibre reinforced thermoplastic skins. These two thicknesses cover the majority of light commercial vehicle floor applications, from lightly loaded campervan builds to heavier cargo and specialist vehicle conversions.
Both options use the same core architecture: a 140 kg/m³ PP-honeycomb core with 4-ply glass-fibre anti-skid skins on both faces. The 15 mm panel has an areal weight of 5,550 g/m² and the 30 mm panel comes in at 7,600 g/m², reflecting the additional core depth. Both panels carry a 66% glass content by weight, which gives them a high strength-to-weight ratio compared to plywood or steel alternatives.
Beyond these two standard configurations, custom thicknesses are achievable by adjusting core depth during manufacturing. If your application sits between these two options or requires something outside this range, panel thickness can be specified to match your exact structural and dimensional requirements.
How does floor thickness affect payload capacity in a van conversion?
Floor thickness directly affects payload capacity because it determines the weight of the floor panel itself. A thinner 15 mm sandwich panel floor weighs less than a 30 mm equivalent, which means more of the van’s gross vehicle weight rating (GVWR) is available for cargo, equipment, or passengers. Every kilogram saved in the floor structure is a kilogram you can convert into usable payload.
This matters even more in 2026 as electric van conversions become more common across European fleets. Lighter body structures extend battery range in electric vans. Every kilogram of structural dead weight reduces range per charge, making weight reduction a range argument as much as a payload argument. EV fleet procurement teams now routinely ask about floor panel weight as part of their vehicle specification process.
Compared to a traditional plywood floor of equivalent thickness, a thermoplastic sandwich panel floor is substantially lighter while offering greater durability. Plywood typically needs replacing every three to five years in commercial use. A composite sandwich panel floor lasts twelve or more years in the same conditions, eliminating two to three replacement cycles over the vehicle’s working life. When you factor in panel cost, installation labour, and vehicle downtime, the composite floor is cheaper per year of service even at a higher unit price.
What load-bearing requirements should determine panel thickness?
The load-bearing requirement that should drive your thickness decision is the maximum point load the floor will experience in service, combined with the span between support points. A floor carrying concentrated loads from heavy equipment, pallet jacks, or wheelchair systems needs higher absolute load capacity than one carrying distributed loads from passengers or light cargo.
Tested under ISO 14125 three-point bending conditions, the 15 mm panel achieves an average maximum load of 3,240 N, while the 30 mm panel reaches an average of 5,647 N in the same test geometry. This difference reflects the greater cross-section depth of the thicker panel, which increases resistance to bending across a span. For applications where the floor spans longer distances between structural supports, the 30 mm panel provides meaningfully higher load capacity.
Compression strength is also relevant where the floor will experience concentrated vertical loads, such as equipment feet or jack stands. The 15 mm panel achieves a compression strength of 4.50 MPa across the full panel section, with the PP-honeycomb core contributing 3.63 MPa on its own. These figures give you a concrete basis for comparing panel performance against your actual load requirements rather than relying on general rules of thumb.
If your conversion involves a subframe or cross-members beneath the floor, a 15 mm panel is often sufficient because the support structure reduces the effective span. Where the panel must be self-supporting across a wider bay, the 30 mm option is the more appropriate choice.
Does floor thickness change depending on the van conversion type?
Yes, the appropriate sandwich panel floor thickness varies significantly depending on the type of van conversion. The intended use, load profile, and structural arrangement of the build all influence which thickness performs best in service.
For campervan and motorhome conversions, a 15 mm panel typically provides sufficient stiffness and load capacity for habitation use. The floor carries distributed loads from furniture, appliances, and occupants, and the panel usually sits on a timber or aluminium subframe that reduces the unsupported span.
For cargo van and refrigerated body conversions, the floor faces heavier point loads from loaded pallets, trolleys, and forklift entry. A 30 mm panel is more appropriate here, particularly where the floor must span between chassis rails without intermediate support. A 30 mm PP sandwich panel floor is self-supporting across typical truck body bay widths, which removes the need for an aluminium subframe and eliminates a production step for the body builder.
For specialist vehicle conversions such as ambulances, mobile workshops, or accessible transport, the load requirements vary widely and thickness should be determined by the specific equipment being installed. Point loads from medical equipment mounts, compressor units, or wheelchair restraint systems can be significantly higher than general cargo loads and may require a thicker panel or localised reinforcement.
What’s the difference between core material and skin thickness in a sandwich panel?
In a sandwich panel, the core material provides the bulk of the panel’s thickness and determines its bending stiffness and compression resistance, while the skins carry the tensile and compressive forces generated when the panel bends. The two work together as a structural system, and changing either one affects the panel’s overall performance in different ways.
The core in a floor panel is the PP-honeycomb layer that makes up most of the panel’s depth. Increasing core thickness increases the distance between the two skins, which raises bending stiffness significantly without adding much weight. This is why a 30 mm panel carries nearly twice the maximum load of a 15 mm panel despite the relatively modest increase in areal weight.
The skins are the glass-fibre reinforced thermoplastic layers bonded to each face of the core. In both the 15 mm and 30 mm floor panels, the skins are 4-ply laminates with a black anti-skid surface finish. Each skin is approximately 1.11 mm thick with an areal weight of 1,625 g/m². The skins carry tensile loads in both the 0° and 90° directions, giving the panel balanced in-plane strength regardless of installation orientation.
When specifying a floor panel, increasing core thickness is the most efficient way to raise bending performance. Increasing skin ply count raises tensile strength and impact resistance but adds more weight per unit of stiffness gain. For most van floor applications, the 4-ply skin with a variable core depth is the right approach to balancing weight, stiffness, and surface durability.
Can sandwich panels be cut to a custom thickness for van floors?
Sandwich panels cannot typically be cut to a custom thickness by reducing the core after manufacture, because the core structure relies on its full depth to function correctly. However, custom panel thicknesses can be specified at the manufacturing stage by adjusting the core depth before lamination. This means you can order a floor panel at an intermediate thickness if neither 15 mm nor 30 mm matches your dimensional requirements.
Custom panel dimensions in length and width are straightforward. Panels are available in dimensions up to 13,500 mm × 2,900 mm, and CNC routing or cutting to your exact floor plan dimensions is standard practice. For van conversions where the floor must fit around wheel arches, seat rails, or body features, panels are cut to your supplied drawings rather than trimmed on-site.
Edge treatment is worth considering alongside custom dimensions. Cut edges expose the honeycomb core, which should be sealed to prevent moisture ingress, particularly in vehicles that are washed down regularly or operate in wet environments. Edge sealing and edge bending protect the core from UV and moisture over the panel’s service life, which is relevant for any floor that will see regular cleaning or outdoor exposure.
How Compoform Helps You Specify the Right Floor Panel
We manufacture thermoplastic sandwich panels for van and vehicle floor applications, and we work with body builders and conversion specialists to match panel configuration to the actual demands of each build. Rather than offering a fixed catalogue, we review your application and recommend the core thickness, skin specification, and panel dimensions that fit your structural and weight requirements.
- Custom thickness and dimensions: Panels are produced to your exact specification, including non-standard core depths and floor plan dimensions up to 13,500 mm × 2,900 mm.
- Self-supporting floor panels: Our 30 mm PP-honeycomb floor panels are self-supporting across standard body bay widths, removing the need for an aluminium subframe and simplifying your assembly process.
- Anti-skid surface finish: Both 15 mm and 30 mm floor panels carry a black anti-skid surface as standard, ready for use without additional surface treatment.
- Long service life: Thermoplastic composite floors last twelve or more years in commercial vehicle use, compared to three to five years for plywood, eliminating multiple replacement cycles over the vehicle’s working life.
- Edge sealing: We can supply panels with sealed or bent edges to protect the core from moisture and UV exposure in wash-down environments.
If you are specifying a floor panel for a van conversion, ambulance build, or cargo body, bring us your load requirements and floor dimensions. We will review the design, confirm the right panel configuration, and flag any integration considerations before production starts, so the panel fits your process, not just your drawings.