At Wuxi GRT Technology Co., Ltd., the "aluminum vs. galvanized steel" debate isn't theoretical-it's a conversation we have with nearly every client during technical review. After engineering mounting systems for residential rooftops in Southern Europe, industrial warehouses across Southeast Asia, and utility-scale arrays in the Middle East, we've learned that material choice isn't about which is "better." It's about which fits your site, budget, and long-term performance goals.
Aluminum 6005-T5: Precision for Weight-Sensitive Applications
When structural load matters, aluminum is our go-to. Its high strength-to-weight ratio makes it ideal for rooftop retrofits where every kilogram counts. Last spring, we supplied a 1.2 MW mounting system for a logistics center in Thailand. The building's concrete roof had a strict load limit of 0.2 kN/m². By specifying 6005-T5 aluminum rails with powder-coated finish, we kept system weight at 0.13 kN/m² while maintaining wind resistance up to 58 m/s. Installation crews reported handling components manually-no crane needed-cutting on-site time by roughly 30%.
From field experience, aluminum delivers:
- Reliable corrosion resistance in humid or coastal zones without additional treatment;
- Lower thermal expansion, reducing stress on module frames during temperature swings;
- Compatibility with pre-assembly workflows, minimizing on-site errors.
One practical note: aluminum shouldn't directly contact dissimilar metals. On a recent coastal project, we added EPDM isolation washers at all steel-aluminum junctions-a small detail that prevents galvanic corrosion down the line.
Hot-Dip Galvanized Steel (HDG): Durability for Ground-Mount and High-Stress Sites
For ground-mounted arrays or high-exposure environments, hot-dip galvanized steel provides the structural rigidity and corrosion protection that utility projects demand. The zinc coating (typically 80–100μm) acts as a sacrificial barrier, delivering 25+ years of service life in most climates.
On a 6 MW ground-mount project in Northwest China, we specified HDG steel piles and brackets to withstand -30°C winters, high UV exposure, and abrasive sand winds. Soil testing showed mildly alkaline conditions, so we applied a supplementary polyester coating to critical connection points. Two years post-commissioning, inspection reports show zero visible degradation. For ground mounts, steel's higher stiffness also minimizes rail deflection under snow load-a factor that directly impacts module warranty compliance.
Trade-offs to weigh:
- Steel's weight may require mechanical lifting equipment, increasing installation time;
- Field-cut edges need zinc-rich paint touch-ups to maintain corrosion resistance;
- When connecting to aluminum-framed modules, isolation hardware prevents bimetallic reactions.
How We Guide the Decision: Real Project Factors
Before recommending a material, we evaluate four practical dimensions:
1. Site environment: Coastal salt spray, industrial pollution, or desert abrasion all influence coating requirements;
2. Structural constraints: Roof load capacity, foundation soil type, and local wind/snow codes;
3. Installation workflow: Does the client prefer pre-kitted components for speed, or field-flexible systems for complex layouts?
4. Lifecycle cost: Aluminum has higher material cost but lower labor; steel offers lower material cost but may need more maintenance in aggressive environments.
Transparent Advice, Not Sales Pitch
We've seen projects compromise reliability for short-term savings. One client initially requested standard galvanized brackets for a seaside hotel rooftop to reduce upfront cost. After running salt-spray testing per ISO 9227 and modeling 10-year maintenance scenarios, we showed them that HDG with supplementary coating reduced replacement risk by over 60%. They approved the upgrade-and avoided premature failure.
Let's Match Material to Your Project
If you're specifying PV mounting systems and need help weighing aluminum vs. galvanized steel, share your site conditions with our engineering team. At Wuxi GRT Technology, we don't push a preferred material-we provide structural calculations, corrosion modeling, and lifecycle cost analysis to support your decision.
