Footwear fault diagnosis: Identifying common issues

First Published: April 2025

Understanding footwear quality issues

Footwear plays a critical role in everyday life, from personal comfort and safety to professional use and self-expression. As a result, the quality and reliability of footwear products directly influence consumer satisfaction, brand perception, and regulatory compliance.

Despite advances in technology and increasingly refined production processes, faults in footwear continue to arise. Whether from material issues, design flaws, or production errors, these faults can lead to product failures, returns, safety concerns, and even reputational damage.

This article explores the most common types of footwear faults, why they occur, and how they can be prevented through proper evaluation, quality control, and compliance with safety standards.

Why footwear fault diagnosis matters?

Footwear is exposed to complex usage patterns, varying environmental conditions, and high consumer expectations for both form and function. Fault diagnosis involves identifying the root causes of issues that affect the performance, safety, or appearance of a product. These faults may originate during the design phase, material selection, manufacturing process, or result from external supply chain factors.

From a consumer perspective, fault-free footwear means:

• Greater comfort and correct fit
• Long-term durability
• Enhanced safety (especially for children and workwear)
• Confidence in the brand and a reduced likelihood of product returns
• Enhanced sustainability through longer lasting footwear and reduced rejects and customer returns

Today’s consumers are both quality-conscious and environmentally aware. Faulty products lead to dissatisfaction, negative reviews, and unnecessary waste.

Common footwear faults and their causes

Understanding the origins of typical faults is essential for manufacturers and quality assurance teams. Some of the most common footwear issues include:

• Sole Separation or Delamination
  • Cause: Poor bonding processes, incorrect surface preparation, incompatible adhesives, or incorrect curing time
  • Impact: Compromises structural integrity, leading to safety concerns or discomfort
• Cracked or Brittle Materials
  • Cause: Substandard raw materials, finish incompatibility, environmental exposure, or improper storage
  • Impact: Aesthetic issues and reduced lifespan, particularly in cold or humid conditions
• Heel Breakage and Fatigue
  • Cause: Inadequate reinforcement, weak construction, or material fatigue under stress
  • Impact: High safety risk, especially in high heels and safety footwear
• Poor Slip Resistance
  • Cause: Incorrect outsole design, inappropriate outsole material selection or insufficient testing against industry standards
  • Impact: Increased risk of slips and falls, particularly in wet or industrial environments
• Size Irregularities and Fit Issues
  • Cause: Inconsistent sizing systems, poor pattern grading, or inadequate quality control
  • Impact: Discomfort, higher return rates, and negative customer feedback
• Discolouration or Material Fading
  • Cause: UV exposure, chemical reactions, or dye instability
  • Impact: Aesthetic degradation and non-compliance with brand specifications
• Scuff Marks
  • Cause: Mishandling during manufacturing or improper packaging during transport
  • Impact: Affects appearance, especially in glossy or leather footwear; reduces perceived quality
• Asymmetry
  • Cause: Misaligned parts or incorrect assembly during production
  • Impact: Crooked seams or uneven left/right shoe alignment; visually noticeable and functionally flawed
• Excessive Glue
  • Cause: Over-application or improper handling of adhesives
  • Impact: Visible glue seepage at joints that compromises the appearance of the product
  • Note: While this is often cosmetic, it can lead to returns due to perceived poor quality
• Safety-Critical Defects: Metal Contamination and Sharp Points
  • Cause: Broken needles, exposed tacks, or misapplied fasteners
  • Impact: Serious risk of injury to the wearer
  • Detection:
    • Shoes without metal components should be screened using a metal detector
    • Shoes with intentional metal elements require strict visual inspection to check for protrusions or sharp edges

Root causes: Where faults originate?

Most footwear issues originate from one or more of the following stages:

• Design & Engineering: Poor load distribution, incorrect fit modelling, or aesthetic decisions compromising durability
• Material Selection: Low-grade or inappropriate materials for intended use conditions
• Manufacturing: Process errors, machinery inconsistencies, or lack of operator training
• Storage & Transport: Exposure to moisture, heat, or pressure that degrades materials or adhesives
• Supply Chain Oversight: Inadequate supplier vetting or insufficient testing of incoming components

Preventative strategies for quality and compliance

Preventing faults requires a proactive and holistic quality assurance approach. Key preventative measures include:

• Material and Component Testing: Conducting thorough testing of raw materials before production begins helps ensure components meet performance, durability, and regulatory requirements.
• Supplier Audits and Validation: Evaluating supplier capabilities and process controls helps minimise the risk of faults introduced by third-party vendors.
• In-Process and Post-Production Inspections: Monitoring quality at multiple stages—during and after manufacturing—improves fault detection and reduces the likelihood of defects reaching the market.
• Adherence to International Standards: Testing and validating products against recognised standards such as EN ISO 20345 for safety footwear or REACH regulations for chemical safety ensures both regulatory compliance and consumer protection.
• Team Training and Process Improvement: Educating design, sourcing, and quality teams about common faults and root causes builds internal expertise and drives continuous improvement.

Partner with Eurofins Softlines & Hardlines for comprehensive footwear testing

Eurofins Softlines & Hardlines provides reliable, globally recognised footwear fault diagnosis and testing services. With decades of experience, a global laboratory footprint, and a comprehensive understanding of footwear standards, we are a trusted partner to leading footwear brands and retailers.

Contact us today to discuss your diagnostic and testing needs. Let’s work together to ensure your footwear products meet the highest standards of quality, safety, and consumer satisfaction.