There are many materials to choose from for roofs and walls, such as aluminum, wood, clay, steel, etc.
This article introduces Galvalume steel material knowledge.
What is Galvalume
The history of Galvalume dates back to the late 20th century when it was developed as an improvement over traditional galvanized steel.
– 1960s: Researchers began experimenting with different coatings to improve the corrosion resistance of steel. The goal was to find a coating that could offer better protection than the traditional zinc coating used in galvanized steel.
– 1972: BIEC International Inc introduced Galvalume to the market. This new product featured a coating composed of 55% aluminum, 43.4% zinc, and 1.6% silicon.
This specific coating composition provides the steel with enhanced corrosion resistance, heat reflectivity, and durability. The aluminum component offers barrier protection, while the zinc component provides galvanic protection, and the silicon helps the coating adhere to the steel.
Galvalume is widely used in various applications, including roofing, siding, and other construction materials. Its resistance to rust and corrosion makes it an ideal choice for environments that are exposed to harsh weather conditions. Additionally, it is often favored for its aesthetic appeal and its ability to maintain its appearance over time.
Advantages of Galvalume Roofing
Durability: Galvalume roofing is known for its long lifespan. The combination of aluminum and zinc coating provides excellent resistance to corrosion and rust, which enhances its durability compared to traditional galvanized steel.
Corrosion Resistance: The aluminum in the coating provides a barrier protection, while the zinc offers sacrificial protection, making it highly resistant to corrosion in various environments.
Heat Reflectivity: Galvalume roofs reflect a significant amount of heat, which can help reduce cooling costs in hot climates. This makes it an energy-efficient option for roofing.
Lightweight: Compared to other roofing materials like tiles or slate, Galvalume is relatively lightweight, which can reduce the structural load on a building and simplify the installation process.
Eco-Friendly: Galvalume roofing is often made from recycled materials and is fully recyclable at the end of its life, making it an environmentally friendly option.
Disadvantages of Galvalume Roofing
Limited Color Choices: Although Galvalume is available in various finishes, the color options may be more limited compared to other roofing materials like shingles or tiles.
Noise: Metal roofs, including Galvalume, can be noisier during rain or hailstorms compared to other roofing materials. This can be mitigated with proper insulation and underlayment.
Thermal Movement: Metal roofing materials, including Galvalume, can expand and contract with temperature changes. This thermal movement can potentially cause issues over time, such as fastener loosening or sealant failure, if not properly accounted for during installation.
Chemical Sensitivity: Galvalume can be sensitive to certain chemicals and environments. For instance, it may not perform as well in environments with high levels of ammonia or where it is exposed to constant salt spray, such as near coastal areas. This can lead to accelerated corrosion in such conditions.
Compatibility with Other Materials: Galvalume should not come into direct contact with certain materials, such as copper or lead, as this can cause galvanic corrosion. Care must be taken to ensure that compatible materials are used in conjunction with Galvalume roofing.
Potential for Oil Canning: Oil canning is a phenomenon where flat metal panels appear wavy or distorted. While it does not affect the structural integrity of the roof, it can be aesthetically displeasing. Proper installation techniques and panel selection can help minimize this issue.
AZ50 and AZ55 Coating
The numbers AZ50 and AZ55 refer to the coating weight, which is the amount of aluminum-zinc alloy applied to the steel substrate.
AZ50 Coating:
– Coating Weight: 0.50 ounces per square foot (oz/ft²) total, which is approximately 0.25 oz/ft² on each side.
– Thickness: Approximately 20 microns.
– Corrosion Resistance: Suitable for most roofing applications, providing good protection against corrosion and weathering.
AZ55 Coating:
– Coating Weight: 0.55 ounces per square foot (oz/ft²) total, which is approximately 0.275 oz/ft² on each side.
– Thickness: Slightly thicker than AZ50, at about 22 microns.
– Corrosion Resistance: Offers enhanced protection compared to AZ50, making it ideal for more demanding environments or applications where higher durability is required.
Applications:
– AZ50: Typically used in residential roofing, light commercial applications, and areas with moderate environmental conditions.
– AZ55: Often preferred for commercial, industrial, and agricultural buildings, or in environments with harsher conditions such as coastal areas.
When choosing between AZ50 and AZ55, consider the specific environmental conditions and performance requirements of your roofing project. Both options provide excellent protection, but AZ55 offers a higher level of durability and longevity.
Uses for Galvalume Roofs and Walls
Galvalume metal roofs and walls are popular in various applications due to their durability, corrosion resistance, and aesthetic appeal. Here are some common uses:
Residential Applications
- Roofing: Galvalume is often used for residential roofing due to its longevity and resistance to rust and corrosion.
- Siding: It is also used for exterior walls, providing a sleek, modern look while offering excellent protection against the elements.
- Gutters and Downspouts: Galvalume can be used for gutters and downspouts because of its ability to withstand harsh weather conditions.
Commercial Applications
- Commercial Buildings: Many commercial buildings use Galvalume for both roofs and walls due to its low maintenance and long lifespan.
- Warehouses: The material is ideal for large warehouses as it can cover vast areas and provide excellent protection against weather.
- Retail Stores: Retail stores often use Galvalume for its aesthetic appeal and durability.
Agricultural Applications
- Barns and Sheds: Galvalume is commonly used for barns, sheds, and other agricultural buildings because it can withstand harsh environmental conditions.
- Grain Silos: It is also used in the construction of grain silos due to its resistance to corrosion from stored materials.
Industrial Applications
- Factories: Factories often use Galvalume for both roofs and walls due to its ability to withstand industrial pollutants and harsh conditions.
- Storage Facilities: Industrial storage facilities benefit from the material’s durability and low maintenance needs.
Where Galvalume Should Not Be Used
Marine Environments: In areas with high salt content, such as coastal regions, Galvalume may not perform well over time due to accelerated corrosion from saltwater exposure.
High Heat Applications: Galvalume is not suitable for applications involving prolonged exposure to temperatures above 500°F (260°C), as its coating can degrade at high temperatures.
Acidic or Alkaline Environments: Environments with high acidity or alkalinity can cause the Galvalume coating to deteriorate, reducing its effectiveness and lifespan.
Direct Contact with Concrete: Galvalume should not be used in direct contact with concrete, as the alkaline nature of concrete can lead to accelerated corrosion.
Industrial Pollution: Areas with high levels of industrial pollution, especially those with sulfur compounds, can cause rapid degradation of the Galvalume coating.
Animal Confinement Buildings: The ammonia and other chemicals found in animal confinement buildings can be highly corrosive to Galvalume.
