Analysis of Common Quality Issues in Aluminum Composite Panel (ACP) Curtain Wall Projects

Introduction

Aluminum Composite Panels (ACP)—also known as aluminum-plastic composite panels—are widely used in modern curtain wall construction due to their lightweight, aesthetic appeal, and excellent weather resistance.

However, during installation and long-term use, ACP curtain wall projects often encounter quality issues such as discoloration, debonding, deformation, and uneven sealant joints. These problems not only affect the appearance of buildings but also compromise their durability and safety.

This article analyzes the most common quality issues found in ACP curtain wall projects and provides practical solutions and preventive measures for construction professionals.

1️⃣ Discoloration and Fading of ACP Panels

Discoloration and fading are among the most common problems with ACP curtain walls. The primary cause is improper material selection—specifically, using indoor-grade panels for outdoor applications.

Cause

• Indoor ACP panels are coated with resin-based paint, which lacks UV and weather resistance.

• When used outdoors, these coatings degrade quickly under sunlight and rain, causing fading and discoloration.

• Outdoor ACP panels, on the other hand, are coated with fluorocarbon (PVDF) resin, known for its excellent anti-aging and UV resistance—but they are more expensive.

⚠️ Common Issue

Some contractors or suppliers mislead clients by selling indoor panels as outdoor-grade PVDF panels to reduce costs and increase profit margins. This deception results in rapid aging and visible color inconsistencies on façades.

✅ Solution

• Always verify the coating type—PVDF for outdoor, polyester for indoor.

• Request manufacturer certifications or coating performance test reports before purchase.

• Establish strict material inspection procedures during procurement.

2️⃣ Debonding and Peeling of ACP Panels

Panel debonding and adhesive failure occur mainly due to the use of incorrect or poor-quality adhesives during installation.

Cause

• The ideal adhesive for exterior ACP installation is neutral silicone sealant, offering superior elasticity, adhesion, and weather resistance.

• In the past, imported silicone adhesives were costly, limiting their use to high-end or high-rise projects.

• Some contractors now substitute quick-drying or low-grade adhesives, suitable only for indoor environments.

⚠️ Consequence

Using non-silicone adhesives in outdoor settings leads to loss of adhesion, panel peeling, and water leakage due to exposure to temperature variations, rain, and UV rays.

✅ Solution

• Use qualified, weatherproof silicone sealant that complies with GB 16776 or ASTM C920 standards.

• Avoid using quick-drying adhesives for exterior projects.

• Implement adhesive sampling tests before large-scale application.

3️⃣ Deformation and Bulging of ACP Panel Surfaces

Deformation or bulging of the ACP surface often occurs due to improper base material selection or installation methods rather than the panel itself.

Cause

• Many installers still use high-density fiberboard (HDF) or wood panels as the base material.

• These materials absorb moisture, warp, and deform when exposed to outdoor conditions such as sunlight and rain.

• Once the substrate deforms, the ACP surface layer also bulges or warps.

✅ Solution

• For outdoor applications, always use a metal framework made of galvanized steel, square tubes, or aluminum profiles.

• Ensure all metal frames are rust-proofed and securely fixed.

• Allow proper expansion gaps between panels to accommodate thermal movement.

4️⃣ Ensuring Neat and Uniform Sealant Joints

Aesthetic presentation is critical in ACP curtain wall systems. Poorly executed sealant joints can severely affect the building’s overall appearance.

Common Mistake

Some workers use the protective film on the panel surface instead of paper masking tape during sealant application to save time.
However, the protective film may tear unevenly when cut, leading to irregular or messy joints.

✅ Solution

• Always use professional masking tape when applying sealant.

• After curing, remove the tape cleanly to leave smooth, uniform joints.

• Regularly inspect sealant lines for cracks or peeling during maintenance.

Conclusion

Aluminum Composite Panels (ACP) have become an essential material in modern architectural façades, valued for their lightweight, versatility, and visual appeal. However, ensuring long-term performance requires careful material selection, proper installation techniques, and strict quality control.

By understanding and addressing these common quality issues—discoloration, peeling, deformation, and sealing defects—contractors and builders can significantly improve the durability, appearance, and safety of ACP curtain wall projects.