3003 VS 3004-H34 Aluminum Coil: Weather Resistance Test for Building Roof

When selecting aluminum coil for outdoor roofing, solar PV mounting systems and exterior cladding, weather performance including UV aging and salt fog resistance directly decides the project's service life. Many architects and procurement teams struggle to choose between 3003 and 3004-H34 anti-rust aluminum coils.

This article compares their UV and salt fog test results, alloy composition and practical application scenarios, and explains why 3004-H34 becomes the preferred substrate for coastal PV roofing and high-end architectural cladding projects worldwide.

1. Alloy Basics

Both 3003 and 3004 belong to 3xxx series aluminum-manganese anti-corrosion alloys.

3003 aluminum coil: Al-Mn alloy, general-purpose rust-resistant aluminum. It offers good formability and moderate atmospheric corrosion resistance, widely used for inland common roofing, gutters and general building panels.

3004-H34 aluminum coil: Al-Mn-Mg upgraded alloy. Added magnesium raises tensile strength and delivers better salt spray & UV resistance. H34 temper provides stabilized half-hard strength, less prone to sagging under wind and snow load. It is the mainstream substrate for PVDF pre-painted aluminum coil in premium construction.

2. Weather Resistance Test Comparison (UV & Salt Fog)

We reference ASTM B117 salt spray test and xenon lamp UV accelerated aging test for side-by-side evaluation:

Salt Fog Performance 3003 performs well in inland, rural and mild industrial environments. But under continuous salt spray in coastal zones, pitting corrosion appears faster. 3004-H34 shows much better resistance against chloride ion erosion. It withstands longer salt fog exposure, making it suitable for C5 coastal high-corrosion environments. When paired with PVDF coating, it delivers outstanding protection against sea salt.

UV Aging Performance Long-term strong UV radiation causes coating chalking, color fading and substrate degradation. 3003 works for inland outdoor roofs with medium UV exposure. 3004-H34 has more stable substrate performance under intense UV. It maintains mechanical integrity, reduces coating cracking risk, and is ideal for long-life exposed roofs such as solar PV rooftops.

3. Strength & Fabrication

3003: easy bending and roll forming, medium strength. Cost-effective for standard inland building roofing. 3004-H34: higher tensile strength, better wind uplift resistance. It keeps good formability for roll profiling into roof panels, without easy cracking during stamping and bending. It handles heavier loads from solar panel installation on rooftops.

4. Application Selection Guide

✅ Choose 3003 aluminum coil if:

Inland residential or regular commercial roofing

Normal gutters, indoor & mild outdoor cladding

Project budget focused, non-coastal environment

✅ Choose 3004-H34 aluminum coil if:

Coastal PV solar roofing systems

High-end commercial facades, airport and stadium roof projects

Locations with high humidity, salt breeze or strong UV radiation

Projects requiring PVDF coating and long-term warranty

5. Final Verdict

3003 is a reliable, economical choice for general inland roofing. However, for coastal construction and solar PV roof projects where salt spray and UV are major threats, 3004-H34 is the top pick. Its upgraded alloy formula delivers superior weather resistance and higher structural stability, perfectly matching the strict requirements of premium global building cladding.

Mingtai Aluminum Limited supplies factory-direct 3003 and 3004-H34 aluminum coil, including PVDF pre-coated substrates for roofing and facade projects. Send your project specifications for free technical data and bulk quotation today.

FAQ

Q: Can I use 3003 for coastal roof? 

A: Not recommended for seaside high salt areas. 3003 substrate will face higher corrosion risk even with coating. 3004-H34 is the safer option.

Q: What coating matches 3004-H34 for coastal PV roof? 

A: PVDF fluorocarbon coating is the best match, offering long-term anti-UV and anti-salt-spray performance.

Q: What temper of 3004 is common for roof coil? 

A: H24 and H34 are widely used. H34 provides higher rigidity for solar panel loaded rooftops.