Which Sandwich Panel Cores Suit Roofs, Walls, and Cold Rooms?

At a glance: Sandwich panel cores suit different priorities: PIR is a common choice for insulated roofs and walls, mineral wool for non-combustibility and acoustic performance, and PU or EPS where thermal efficiency and project-specific costs guide selection. For cold rooms, assess the complete panel system, including thickness, joints, facings and operating conditions.

For panel manufacturers, the core choice affects both the finished product and the equipment needed to make it. Comparing sandwich panel cores means looking beyond insulation: fire requirements, panel dimensions, production volume and the intended building or vehicle use also matter.

A core’s properties do not determine a panel’s performance alone. Facings, bonding, joints and installation all contribute, so confirm requirements for the complete panel assembly before settling on a material.

What is a sandwich panel, and what does its core do?

A sandwich panel combines two facings with a bonded core that contributes to insulation, rigidity, and other performance characteristics. The core separates the metal facings, while the bond helps the layers act together as a panel.

Core material affects thermal conductivity, fire performance and acoustic insulation, but it is not a stand-alone guarantee of any rating. Thickness, facing profiles, joint design and production quality also influence performance. That is why sandwich panel cores should be compared against the panel’s intended use, not in isolation.

Sandwich panel cores: how do PU, PIR, mineral wool, and EPS compare?

PU, PIR, mineral wool and EPS each suit different combinations of insulation, fire and acoustic needs. The table gives a starting point; actual performance depends on the product design and complete panel assembly.

Criterion	PU	PIR	Mineral wool	EPS
Insulation	Efficient; thickness matters	Efficient; verify product data	Generally lower insulation per thickness	Insulating; grade and thickness matter
Fire considerations	Verify assembly classification	Verify assembly classification	Non-combustible core; assembly still matters	Combustible; check project requirements
Acoustics	Not usually the primary choice	Not usually the primary choice	Often selected for acoustic needs	Not usually the primary choice
Typical applications	Walls, roofs, cold rooms	Walls and roofs	Walls and roofs with fire or acoustic priorities	Applications meeting its performance limits
Manufacturing implications	Foam metering and mixing	Foam process suited to PIR system	Wool handling and bonding	Core feeding and bonding

PU core: efficient insulation for suitable applications

Polyurethane (PU) cores offer thermal insulation in a relatively light panel. They can suit roofs, walls and cold-room panels, provided the panel thickness, joints and fire requirements fit the project. Among sandwich panel cores, PU can be a practical option where insulation and application-specific cost guide the choice.

• Strength: Supports insulated panel designs for several applications.
• Limitation: Fire performance must be assessed for the complete panel, not inferred from the foam alone.

PIR core: thermal performance with fire behavior to verify

Polyisocyanurate (PIR) is used in insulated roofs and walls where thermal performance and fire behavior both need careful review. Compare tested product and assembly data; the material name alone does not establish a fire rating.

• Strength: Combines insulation with a formulation often chosen when fire behavior is a key consideration.
• Limitation: Results vary by panel design, facings and test criteria.

Mineral wool core: non-combustibility and acoustic benefits

Mineral wool is suited to projects prioritizing a non-combustible core or acoustic insulation. It may require different handling and bonding arrangements from foam-based sandwich panel cores.

• Strength: Provides non-combustibility at the core and can support acoustic objectives.
• Limitation: Check insulation needs, panel weight and production requirements together.

EPS core: an option for projects with specific performance and budget needs

Expanded polystyrene (EPS) can suit projects where its insulation, cost and application limits meet the specification. Confirm fire requirements before choosing EPS; it is combustible, and acceptance depends on the intended use and applicable rules.

• Strength: Can be considered where the specified performance and budget align.
• Limitation: It may not suit projects with demanding fire or operating requirements.

How do you choose a core for roofs, walls, or cold rooms?

Choose a core by weighing the building’s thermal, fire, acoustic, and structural requirements alongside panel thickness and joint design. Match sandwich panel cores to the use case, then verify the complete panel specification.

For roofs and external walls

Compare insulation targets, fire requirements, roof or wall profile, support spacing and exposure conditions. The panel’s load capacity and fixing method must suit the structure; a core choice cannot compensate for unsuitable design.

For cold rooms and refrigerated vehicle bodies

Prioritize insulation, continuous panel joints and control of air leakage. Operating temperature, door openings and moisture conditions affect system needs. For vehicle bodies, account for the body design and service conditions as well as the panel itself. See cold-chain panel production considerations.

For panel fixing details and construction

Specify fasteners, support points, joint geometry, facing thickness and installation tolerances. These details affect stability and thermal continuity, including at corners and openings. For more on panel forming, review rollforming line technology.

What should manufacturers specify for a sandwich panel production line?

Specify the target core materials, panel types, dimensions, capacity needs, and process requirements before selecting a production line. The right configuration depends on how sandwich panel cores will be processed and on the product range the factory intends to make.

Continuous or discontinuous production

A continuous production line suits ongoing production of defined panel types; a discontinuous hydraulic press can offer flexibility for batches and varied panel dimensions. Compare expected output, changeover needs and process constraints rather than treating either approach as universally better.

PU-PIR, mineral wool, and single-panel configurations

PU and PIR lines require a foam system matched to the selected chemistry and process. Mineral wool production calls for suitable core handling and bonding. A single panel production line may fit a narrower product scope; its application and dimensions should be stated upfront.

Project requirements from uncoiling to packing

Set out the full process, from coil handling and rollforming through core placement, bonding, cutting and packing. Manufacturing process choices also shape line configuration.

1. List core materials, facing types, panel profiles and thickness range.
2. Define panel widths, lengths, target capacity and product changes.
3. Describe foam, bonding, pressing, cutting and handling requirements.
4. Specify quality checks, utilities, layout limits and packing needs.

A useful project specification connects each product requirement to a process step, so the proposed line can be assessed against the actual product range.

Make the final choice against the panel specification

Choose sandwich panel cores by starting with the building or vehicle requirement, then checking thermal, fire, acoustic and structural criteria for the complete panel. If the decision is still open, compare product data and test evidence for the intended thickness, joints and facings.

• If insulation is the main driver for a suitable roof or wall, compare PU and PIR panel systems.
• If non-combustibility or acoustics leads the brief, assess mineral wool panels.
• If the application and project requirements permit it, consider EPS against the specification.
• If the product is for a cold room or vehicle, verify the whole system and operating conditions.

Source: DONEM MAKINA — the information in this article is based on the experience and expertise of the DONEM MAKINA team. Last reviewed: October 31, 2026.

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