Introduction
Choosing the right thickness for ACP sheets (Aluminium Composite Panels) is one of the most critical decisions in façade design, signage production, and interior cladding. While ACP panels all share the same basic structure — two aluminium skins bonded to a core — their thickness significantly affects performance, durability, weight, and cost.
The most common ACP sheet thicknesses used worldwide are 3mm, 4mm, and 6mm. Each serves a different purpose depending on installation type, wind load, building height, and environmental conditions. This guide explains the differences clearly so you can choose the correct thickness for your project.
What ACP Thickness Really Means
ACP thickness refers to the total panel thickness, including:
- Aluminium skin thickness (typically 0.18mm, 0.21mm, 0.25mm, 0.30mm, or 0.50mm)
- Core thickness (LDPE or FR core)
A “4mm ACP panel” therefore includes:
- Two aluminium skins
- A core that brings total thickness to 4mm
Different thicknesses change rigidity, impact resistance, lifespan, and allowed applications.
3mm ACP Sheets: Best for Interiors & Signage
Where used:
- Indoor wall cladding
- Corporate interiors
- Retail branding
- Signboards for shops, malls, and exhibitions
- Indoor partitions
Why choose 3mm Aluminium Composite Panels:
- Lightweight
- Easy to cut and bend
- Cost-effective
- Ideal for areas with no wind load
- Perfect for small-format signage
Limitations:
- Not suitable for high-rise façades
- Lower rigidity
- Vulnerable to wind pressure outdoors
Conclusion for 3mm:
Use 3mm ACP only for indoor or low-stress applications.
4mm ACP Sheets: The Global Standard for Building Façades
Where used:
- External façades of commercial buildings
- Residential villas
- Balcony cladding
- Soffits and canopies
- Mid-rise and high-rise buildings
- FR-grade ACP for fire-rated installations
Why 4mm ACP is the international default:
- Strong enough for façade systems
- Good balance of durability and weight
- Suitable for windy coastal areas
- Compatible with both riveted and cassette (tray) systems
- 4mm FR ACP meets many global fire-safety requirements
Conclusion for 4mm:
Choose 4mm Aluminium Composite Panels for almost all exterior projects.
6mm ACP Sheets: For Extra Rigidity & Special Engineering Needs
Where used:
- High-rise buildings exposed to extreme wind loads
- Airports, transport hubs, commercial towers
- Heavy-duty industrial cladding
- Special architectural elements requiring maximum stiffness
- Structural signage on highways
Why 6mm ACP matters:
- Superior rigidity
- Maximum flatness
- Higher wind-pressure resistance
- Necessary for tall structures in windy climates (Gulf region, coastal areas, open terrains)
Limitations:
- Higher cost
- Heavier material
- More difficult to fabricate
Conclusion for 6mm:
Choose 6mm ACP only when engineers specify it or when your façade demands extreme wind-load resistance.
ACP Thickness Comparison Overview
3mm ACP → Best for interiors, signage, branding
4mm ACP → Industry standard for exterior façades
6mm ACP → For high-rise towers and engineering-driven projects
When in doubt, the safest choice for building façades is almost always 4mm Aluminium Composite Panels.
How Climate Affects Thickness Selection
Hot Climates (Gulf, Middle East, Africa)
- Intense sunlight and thermal expansion
- Use 4mm FR or 6mm ACP for high-rise buildings
- Avoid thin skins (0.18mm skins not recommended)
Cold Climates (Europe, Baltics, Canada)
- Freeze–thaw cycles require better rigidity
- 4mm ACP with 0.21–0.30mm aluminium skins is sufficient
Coastal Areas
- Strong winds demand stiffer materials
- Consider 6mm or reinforced 4mm cassette installations
Choosing the Correct Aluminium Skin Thickness
This is more important than total ACP thickness.
For façades, choose:
- 0.25mm aluminium skin (minimum)
- 0.30mm or 0.50mm for premium projects
Thin skins (<0.21mm) reduce durability and dent resistance.
Final Recommendation
- For façades → 4mm ACP (FR Grade Preferred)
- For high-rise towers → 6mm ACP
- For interior or signage → 3mm ACP
If you need strong durability, wind resistance, and long-term performance, 4mm Aluminium Composite Panels provide the best cost-to-performance ratio.
Explore our full range of Smartcon Aluminium Composite Panels, designed for architects and modern projects.
Authored by Smartcon Int’l. Trade & Marketing Ltd. on 30.11.2025. All rights reserved.