Sandwich panels: what they are and where they are used

Summary

• What is a sandwich panel 
• Types of sandwich panels
• Why choose sandwich panels 
• Composition: skins and cores
• How to select the right panel
• Typical applications
• In-depth look
• Industry standards and certifications
• Design, processing, and finishes
• Quick FAQs
• Resources & contacts

What is a sandwich panel

In industrial and construction materials, sandwich panels are synonymous with efficiency and innovation. They are valued for their light weight, aesthetic finishes, compressive and tensile strength, insulation, rigidity, versatility in both use and processing and durability. 

A sandwich panel is a composite consisting of three layers:

• two strong outer skins
• a lightweight central core.

This structure outperforms a solid sheet of equal thickness: the skins absorb mechanical stress, while the core provides stiffness and stability. By combining different materials for skins and cores, a wide range of variants and  finishes can be created.  

Types of sandwich panels

Sandwich panels can be categorized based on the materials used and their intended applications. While there is no universal classification system, they are commonly grouped into three main families:

Insulated sandwich panels: mainly used in construction for roofs and cladding, offering thermal and acoustic insulation.
Visual communication panels: usually made with foam cores and printable skins, popular for signage, exhibition stands and lightweight design.
Composite sandwich panels: all sandwich panels are composite, since they combine different materials. However, the term composite sandwich panels often refers to high-performance products made with skins of aluminium, fibreglass, carbon fibre or HPL, combined with lightweight cores such as honeycomb or structural foams.
From here on, we will focus specifically on composite sandwich panels, which are the core subject of this article.

Why choose sandwich panels

While insulated panels are primarily designed to provide thermal insulation in construction and visual communication panels are used in lightweight, temporary setups, sandwich panels offer a range of advantages that significantly broaden their applications:

• Reduced weight compared to traditional solid materials
• High stiffness thanks to their three-layer structure
• Mechanical resistance to compression and bending
• Ease of processing and assembly
• Customization in terms of materials, thicknesses, dimensions and finishes
   

Composition: skins and cores

External skins
The outer skins of sandwich panels can be in different materials: aluminium, anti-slip (tread) aluminium, stainless steel, HPL (high-pressure laminate), marine plywood, fibreglass or carbon fibre. The choice of skin directly affects the panel’s final performance and its suitability for specific uses and environments.

• Sandwich panels with aluminium skins: lightweight and resistant, easy to process, available in a wide variety of surface finishes.
• Sandwich panels with stainless-steel skins: known for their corrosion resistance, mechanical strength and long service life. 
• Sandwich panels with HPL skins: highly resistant to abrasion, scratches, moisture, heat and impact. They are easy to maintain and available in many colours and finishes.
• Sandwich panels with marine plywood skins: appreciated for their lightness, workability and resistance to humidity. 
• Sandwich panels with fibreglass skins: extremely versatile, offering an excellent stiffness-to-weight ratio. They are used in many industries and can also be designed for waterproofing or backlighting.
• Sandwich panels with carbon fibre skins: ultra-lightweight and rigid, with outstanding mechanical performance, widely used in high-tech applications.

Discover the Compocel and Alustep series

Internal cores

Just like the skins, the choice of the core directly impacts properties such as weight, insulation and strength, making the panel suitable for specific applications and environments.
Cores can be either honeycomb structures or foams.

Honeycomb structures 

• Aluminium: aluminium honeycomb is one of the most widely used cores thanks to its excellent stiffness-to-weight ratio. The micro-perforated version improves ventilation and is particularly used in wind energy and HVAC sectors.
• Nomex: honeycomb made of aramid paper impregnated with phenolic resin, lightweight yet strong, ideal for high-performance applications.
• Polyproylene: polypropylene honeycomb is a thermoplastic honeycomb core, lightweight and moisture-resistant. 
• Polycarbonate: polycarbonate honeycomb is a lightweight honeycomb material with excellent impact resistance.

Schiuma

• PET: PET foam is a lightweight, sustainable structural foam, often produced from recycled materials.
• PVC: PVC foam is a rigid, versatile structural foam.
• PMI: PMI foam is a high-performance foam, very rigid, with excellent thermal stability at elevated temperatures.

Typical applications

Sandwich panels are used across many industries, often “hidden” behind coverings or finishes. Thanks to the variety of available cores and skins, they can be adapted to a wide range of applications.

• Construction and architecture: ventilated façades, raised floors, wall cladding, ceilings and interior design
• Transportation: railway and metro compartments, shipbuilding and marine industry, aerospace, automotive, motorhomes and special vehicles
• Industry: clean rooms, machine tools, ventilation and air systems, screen printing, technical packaging and lightweight plant components
• Special applications: weight reduction for marble and natural stone, panels for interior design, customized solutions for architecture and engineering
• Furnishing for collective spaces: partition walls for high-traffic restrooms such as schools, universities, airports, locker rooms and other public facilities. Visit the dedicated website

Discover all applications of sandwich panels

Industry standards and certifications

In many sectors, sandwich panels must comply with specific standards and certifications, including:

• Railway: EN 45545 standard for fire reaction
• Naval: IMO MED (Mod. B and D) and US Coast Guard approvals
• Construction: EN 13501-1 fire performance certifications and compliance with American Standards (for the USA only)

Design, Processing, and Finishes

Sandwich panels can be processed and customized according to specific requirements:

• Cutting, milling, drilling and edging
• Curving or special shaping
• Aesthetic finishes: painting, decorative laminates, protective films, treatments
• Integrated accessories: fastenyng systems, metal inserts

This makes them suitable for both standard solutions and tailor-made architectural and industrial projects.

Quick FAQ