3 Tipos de Revestimientos de Aluzinc para Cubiertas Metálicas con Revestimiento de Piedra: Desglose técnico y guía de selección

SKW Engineers Explain Why Back Coating Durability Matters More Than You Think

Introduction: Back Coating—The Unsung Hero of Metal Roofs

Stone – coated metal roofs often draw attention to their front – facing stone granules, but the aluzinc back coating is the quiet protector of the roof’s longevity. Here’s the significance:

• Corrosion Resistance: It prevents rust in humid and acidic environments.
• Aesthetic Integrity: Stops the backside from discoloring, which could show through ceilings.
• Structural Protection: Strengthens the metal core to avoid warping.

Chapter 1: 3 Aluzinc Back Coating Technologies Unveiled

1. Fingerprint – Resistant Coating

• Mechanism: A thin, glaze – like film (either transparent or green) is applied using the roll – coating method.
• Pros:
  • It’s cost – effective for projects with a tight budget.
  • The production process is quick, allowing for a fast turnaround.
  • It provides basic scratch resistance for minor damages during handling.
• Contras:
  • Durability Limitation: It fails after 3–5 years. The ASTM B117 salt spray test shows rust formation after 500 hours.
  • Environmental Vulnerability: It peels off in environments with a pH range of 2–12, which is common in industrial areas.
• Ideal Use Cases: Short – term residential projects (less than 5 years) or temporary structures.

2. Back – Painted Coating

• SKW Innovation: A multi – layer system consisting of a primer, topcoat, and curing agent, with proprietary additives.
• Pros:
  • Longevidad: It comes with a 15–20+ years warranty, and premium formulations can last even longer than 20 years.
  • Aesthetic Flexibility: It can match various architectural styles, such as terracotta red for heritage buildings.
  • Moisture Barrier: It seals the metal from humidity, which is crucial in coastal and tropical climates.
• Lab Data:
  • In the QUV Aging Test (5,000 hours), the color change ΔE is less than 3 (according to ISO 4892, this means negligible color fade).
  • In the Salt Spray Test (ASTM B117), there is no rust formation after 1,500 hours.
• Industry Legacy: With over 50 years of pre – painted metal technology, its stability is proven.
• Ideal Use Cases: Long – term residential and commercial projects, buildings in humid climates, and projects where aesthetics are a key focus.

3. Polymer Nanofilm

• Mechanism: A fluorocarbon film is laminated to the steel, and this technology was originally used for livestock facilities.
• Pros:
  • Extreme Chemical Resistance: It can withstand a pH range of 2–12 for short – term use.
  • Temporary Protection: It’s suitable for industrial zones with immediate corrosion risks.
• Contras:
  • Durability Flaw: It peels off after 5–8 years, having the same adhesion problem as fingerprint – resistant coatings.
  • Cost Inefficiency: It’s 30% more expensive than back – painted coatings but offers no long – term value.
• Case Study: A livestock farm in Shandong experienced 60% film peeling after 6 years, which led to rust formation.
• Ideal Use Cases: Short – term industrial projects (less than 8 years) in areas with extreme chemical exposure.

Chapter 2: Technical Comparison Matrix

Feature	Fingerprint – Resistant	Back – Painted (SKW)	Polymer Nanofilm
Vida útil	3–5 years	15–20+ years	5–8 years
Coste	Low ($/m²)	Moderate	High
Corrosion Resistance	Poor (500hr salt spray)	Excellent (1,500hr salt spray)	Good (1,000hr salt spray)
Aesthetic Customization	Limited (2–3 colors)	High (10+ colors)	Low (1–2 colors)
Humidity Resistance	Poor (85% RH failure)	Excellent (85% RH stable)	Moderate

Chapter 3: SKW’s Back Coating Competitive Edge

SKW doesn’t just “offer coatings”; we engineer solutions for real – world challenges:

1. Custom Formulations:
   • Moisture – resistant additives are added for tropical and humid climates.
   • Mildew – inhibiting agents are included to prevent black spots during rainy seasons.
2. Process Excellence:
   • Paint Thickness: Ranges from 8–12μm (the industry average is 5–7μm, and our thicker coating provides better corrosion resistance).
   • Curing Precision: Uses 220℃ oven curing, which prevents the paint from becoming brittle due to temperature swings.
3. Warranty Leadership: We offer a 20 – year guarantee for back – painted coatings. If the coating fails, we will replace it for free.

Chapter 4: Buyer’s Guide—Avoid Back Coating Scams

1. Demand Test Reports:
   • For back – painted coatings, the salt spray test should last for at least 1,000 hours (ASTM B117).
   • For nanofilm, the fluorocarbon content should be at least 70% (tested by FTIR spectroscopy).
2. Inspect Thickness: Use a micrometer. Back – painted coatings must have a thickness of at least 8μm.
3. Warranty Fine Print: Make sure the warranty covers back coating failure (not just the front stone layer).
4. On – Site Bend Test: Bend a sample 180°. Back – painted coatings should not show any cracks.

Chapter 5: Future of Aluzinc Back Coatings

Industry trends indicate the following:

• Bio – Based Coatings: These reduce VOCs while maintaining durability.
• Self – Healing Technologies: Microcapsules that can repair scratches.
• AI – Driven Quality Control: 100% coating inspection using machine vision.

Conclusion: Invest in the Right Back Coating

The back coating is the “invisible shield” that determines the lifespan of your roof. For long – term durability and aesthetic control, SKW’s back – painted coating is the gold standard.

👉 Take Action:

• Download our Back Coating Technical Guide: [https://skwroof.com/download/]
• Request a free coating sample: [https://skwroof.com/contact-us/)