Galvalume vs Galvanized Roofing Sheets — Which One Is Right for Your Industrial Project in South India?
Every year, thousands of procurement heads across Karnataka, Tamil Nadu, and Andhra Pradesh place orders for roofing sheets — and a significant number choose between galvalume and galvanized steel without a clear understanding of what makes them different. Both are excellent materials. Both are widely available. But they are not interchangeable, and specifying the wrong one for your project environment can cost significantly more in the long run than the price difference at purchase.
This guide covers what you need to know before you decide.
The Core Difference: Coating Composition
Galvanized sheets are coated with pure zinc. Galvalume sheets are coated with an alloy of 55% aluminium, 43.5% zinc, and 1.5% silicon. That difference in coating composition drives significant differences in how each sheet performs over its service life.
Corrosion Resistance
Galvalume outperforms galvanized steel in corrosion resistance by a factor of 2 to 4 times in most environments. The aluminium in the galvalume coating provides long-term barrier protection, while the zinc component provides sacrificial protection at cut edges and scratches. This makes galvalume the stronger specification for coastal locations, chemical environments, and any project where long service life with minimal maintenance is a priority.
Heat Reflectivity
Galvalume’s aluminium-rich coating reflects more solar radiation than galvanized steel – making it a better thermal performer for industrial buildings in South India’s high-heat climate, where roof surface temperatures regularly exceed 70°C in summer. For facilities in Tamil Nadu and Andhra Pradesh where peak summer conditions are extreme, this difference in thermal performance directly affects internal temperatures and cooling energy costs.
Cost Comparison
Galvanized sheets are generally more cost-effective upfront than galvalume. For projects with tighter budgets and non-aggressive environments – agricultural sheds, temporary structures, inland locations with low humidity – galvanized steel often delivers the better value proposition. The decision should factor in the full project lifecycle, not just the upfront purchase price.
When to Choose Galvalume
- Coastal locations in Kerala, Tamil Nadu, and Andhra Pradesh (within 10 km of the coast)
- Chemical plants, fertiliser facilities, or industrial environments with airborne pollutants
- Any project specifying a 25+ year service life with minimal maintenance
- Facilities where re-roofing would be operationally disruptive or prohibitively expensive
- PPGI or PPGL colour-coated sheet applications – galvalume substrate outperforms galvanized
When to Choose Galvanized
- Inland locations with moderate humidity in Karnataka, Telangana, and northern Tamil Nadu
- Projects with shorter design lives of 10–15 years
- Agricultural structures, rural sheds, and low-occupancy utility buildings
- Applications where upfront material cost is the primary procurement constraint
- Locations requiring a specific tensile grade (240–550 MPa) in standard gauge options
Our Recommendation for South India
For most industrial and commercial projects across South India’s coastal belt – including the entire Kerala coastline, the Chennai metro and coastal Tamil Nadu, and the Andhra coast – galvalume is the clear specification choice. For inland Karnataka, inland Telangana, and non-coastal Tamil Nadu industrial projects, galvanized sheets deliver strong performance at a more competitive price point.
Conclusion
Both materials have a place in South India’s industrial roofing market. The right choice depends on your project location, environmental exposure, budget, and design life requirement. At Astal Roofing Industries, we supply both Bare Galvalume Sheets and Bare Galvanized Roofing Sheets from our Bengaluru manufacturing facility – and our team is available to advise on the right specification for your specific project. Contact us at sales@astalroofing.in or call +91 97403 32800
