Metal cladding rust

Types of Metal Cladding Rust

Metal cladding rust is the oxidation of metal, particularly iron and steel. It occurs when metal is exposed to moisture and air over time. Different types of rust can form on metal cladding, including:

• Surface Rust: This type of rust is commonly found on metal cladding exposed to moisture. It appears as a reddish-brown color and can be easily removed. Though it doesn't affect the structural integrity of the metal, it should be removed to prevent further rusting.
• Active Rust: This type of rust forms when moisture is present. It appears as a flaky and powdery substance and indicates that the metal is continuing to oxidize. Active rust needs to be treated immediately to prevent further damage to the metal.
• Scale Rust: Scale rust forms when the metal has oxidized for a long time. It creates a thick layer of rust that's bonded to the metal surface. It is challenging to remove scale rust, and in some cases, it may require professional treatment.
• Deep Rust: Deep rust is the most severe form of rust cladding can experience. It occurs when the metal has been oxidized for an extended period. Deep rust can cause holes and structural damage to the metal. In most cases, the only solution to deep rust is to replace the affected metal cladding.

Besides these types, there are also different colors of rust that can form on metal cladding, including:

• Brown Rust: This is the most common type of rust and is usually seen on iron and steel. It appears as a brown flaky substance and forms when the metals oxidize.
• Yellow Rust: Yellow rust is commonly caused by exposure to water and moisture. It appears as a yellow powdery substance and indicates that the metal cladding is oxidizing.
• Orange Rust: This type of rust is formed when the metal cladding reacts with air and water. It appears as an orange flaky coating on the metal surface.
• Red Rust: Red rust forms when the metal is exposed to air and moisture for a long time. It creates a thick layer of rust that is difficult to remove.
• Black Rust: Black rust is often considered a protective layer. It forms when the metal cladding is exposed to moisture and air for a short period of time. It creates a thin layer of rust that prevents further oxidation.

Functions and features of metal cladding rust

Metal cladding is used on exterior building surfaces like walls, roofs, and canopies. It is also used on interior spaces like parking garages, interior walls, ceilings, and fire-rated walls.

Below are the functions of metal cladding:

• Protection: Metal cladding protects against harsh weather conditions. These include wind, rain, snow, and extreme temperatures. It acts as a barrier, shielding the building's interior from water damage, moisture, and debris.
• Structural Integrity: Metal cladding helps maintain the structural integrity of a building. It ensures the building remains dry and protects the framework from rot and decay caused by moisture.
• Insulation: Metal cladding provides insulation to a building. It helps to keep buildings warm during winter and cool during summer. This is because certain types of metal cladding have insulation materials installed between the metal panels and the building's structure.
• Metal cladding rust enhances the appearance of a building. It comes in different styles, colors, and finishes that give a building a modern and attractive look.
• Durability: Metal cladding is durable. It ensures the long-term protection of buildings with little or no maintenance required.

Below are the features of metal cladding:

• Materials: Metal cladding is made of different metals, including aluminum, steel, copper, zinc, and corten steel. It is lightweight and durable.
• Design and Aesthetics: Metal cladding comes in different designs and finishes. These include corrugated, smooth, ribbed, standing seam, shiplap, and flat seam. The finishes include painted, galvanized, mill finish, textured, powder coating, and stone coating.
• Installation: Metal cladding is easy to install and requires a small workforce. It is also easy to maintain and repair in case of any issues.
• Customization: Metal cladding is highly customizable. It comes in different shapes, sizes, and designs that suit the needs of different buildings.
• Cost-effective: Even though metal cladding has a high initial cost, it is cost-effective in the long run. This is because it requires little or no maintenance and is highly durable. Metal cladding also provides easy and quick installation, which saves on labor costs.

Scenarios of Metal Cladding Rust

While stainless steel and aluminum are the most commonly used types of cladding, other metals are also used. These include copper, CORTEN (weathering) steel, and galvanized steel. Each of these metals offers a unique aesthetic, and some develop protective patinas that are sought after for their appearance.

Cladding copper and galvanized steel are examples of metal cladding that can corrode under certain circumstances. However, as outlined above, the corrosion also leads to a protective layer. The scenarios in which this type of metal cladding rust occurs include:

• Galvanized Steel:

  Scenarios of Corrosion:

  Moisture: Prolonged exposure to water (rain, dew, or humidity) can lead to the breakdown of the zinc coating, especially in galvanized steel that has been cut or scratched.

  Electrolytic Action: Contact with different metals (like screws or parts) in the presence of water can create an electrolytic cell, accelerating corrosion.

  Soil: Buried or partially buried galvanized steel (like fence posts or culverts) is prone to corrosion due to moisture and electrolytes in the soil.

• Copper:

  Scenarios of Patina Formation:

  Moisture: Rainwater or high humidity can lead to the development of a green patina (copper carbonate) on copper cladding, which is often desired for its appearance.

  Air: Exposure to air allows copper to form a patina over time, changing its color from a reddish-brown to a greenish-blue. This process is slow but continuous.

  Pollutants: In urban areas, air pollutants (like sulfur dioxide) can accelerate the patina formation process on copper.

• CORTEN Steel:

  Scenarios of Rust Formation:

  Moisture: CORTEN needs exposure to water to form a stable, protective rust layer (patina) that gives it a reddish-brown color.

  Air: Oxygen is required to create the protective rust layer on CORTEN steel.

• Conclusion:

  While galvanized steel, copper, and CORTEN steel can "rust," this process often leads to the formation of protective layers (zinc coating, patina, or rust layer) that shield the metals from further corrosion. Understanding these scenarios helps in selecting and maintaining these materials for architectural purposes.

How to choose metal cladding rust

• Consider the environment:

  The environment where the metal cladding will be installed greatly influences its rust resistance. Areas with high humidity, coastal proximity, or salty air increase corrosion risk. In such environments, choosing a rust-resistant metal like galvanized steel or aluminum is essential. These metals have coatings or finishes that withstand moisture and salt, preventing rust formation. On the other hand, arid regions may allow the use of uncoated steel cladding, which develops a protective rust patina. Assessing environmental factors helps select cladding best suited to withstand local conditions and prolong its lifespan.

• Evaluate coating options:

  When selecting metal cladding, it's crucial to examine the various coating choices available. Each coating serves to bolster the metal's inherent resistance against rust and corrosion while also influencing its appearance. Common coatings worth considering include galvanization, where zinc is applied to steel; aluminum's natural oxidation process that forms a protective layer; and paint coatings that come in various colors and finishes. Understanding how each coating works and the level of protection it provides will ensure an informed decision that aligns with both functional requirements and aesthetic preferences for a project.

• Assess maintenance requirements:

  One essential factor to consider when choosing metal cladding is the required upkeep to keep it in optimal condition. Different types of metal cladding come with varying levels of maintenance commitment, which can significantly impact their long-term performance and cost-effectiveness. For instance, some metal cladding options may require regular cleaning to prevent the buildup of dirt and debris, which can lead to corrosion over time. On the other hand, certain types of metal cladding may be virtually maintenance-free, thanks to their natural ability to develop a protective patina or coating that shields them from the elements.

metal cladding rust Q&A

Q: How can someone prevent rust on their metal cladding?

A: To prevent rust on metal cladding, one can use galvanized steel or opt for stainless steel or aluminum cladding. Additionally, applying a protective coating or paint can help prevent moisture contact with the metal.

Q: Is rust ever beneficial to metal cladding?

A: While rust is generally not favorable, patina, a protective layer formed by rust, can develop on weathered galvanized or corten steel cladding. This layer helps prevent further corrosion by forming a barrier.

Q: How does one remove rust from metal cladding?

A: Rust can be removed from metal cladding using abrasive methods like sanding or wire brushing, and chemical rust removers. After removing the rust, a protective coating or paint should be applied to prevent future corrosion.

Q: What should someone do if their metal cladding is severely corroded?

A: If the metal cladding is severely corroded, it may require replacement. Consulting with a professional to assess the extent of the damage and determine the best course of action is important.

Q: Are certain climates more detrimental to metal cladding?

A: Climates with high humidity, saltwater exposure (near oceans), and frequent rain or snow tend to be more challenging for metal cladding. These conditions increase the likelihood of moisture, which accelerates rust formation.