Metal roofing is a popular choice for commercial properties because it is durable, long-lasting, and can withstand harsh elements. 

But even the strongest materials can have challenges and one of them is metal roof rust. Rust not only ruins the look of your roof but can weaken the structure over time.

Stopping rust is key to maintaining your roof’s performance and your investment. For example, studies show that untreated steel can rust quickly in high-moisture environments, coastal areas are particularly at risk.

In this article, we will review the causes of metal roof rust, the solutions, and maintenance tips to keep your roof looking great for years to come.

Understanding the Causes of Metal Roof Rust

Rust occurs when iron alloys in metal roofing materials react with oxygen and moisture, resulting in a reddish-brown layer called iron oxide. 

Source: Rust Bullet

Metal roofing is designed to resist rust, but certain factors can accelerate corrosion. These include: 

• Exposure to Moisture and Humidity: Continuous exposure to moisture, rain, snow or high humidity increases the risk of rust. This is more problematic in coastal areas where salt spray accelerates the corrosion process.

• Poor Quality Materials: Using low grade or improperly treated roofing materials can lead to premature rusting. Roofs made of underlying steel without proper coating for example are more prone to rust and corrosion.

• Lack of Proper Maintenance: Not doing regular maintenance can leave small issues like scratches or exposed areas unaddressed. Over time, these minor problems can allow moisture to penetrate the protective layer and cause further corrosion.

• Damage to the Protective Coating: The coatings applied to steel roofs are a shield against rust. But damage caused by scratched surfaces, cut edges, or improper handling during installation can breach this barrier and expose the metal to the elements.

Prevention Strategies

Stopping rust on your metal roof starts with proactive measures and proper care. 

By addressing the risks and doing regular maintenance, you can extend the life of your roof and avoid costly repairs. 

Here are the solutions to keep your metal roof rust-free.

Regular Inspection

Regular inspections are key to your metal roof’s longevity and preventing rust. Catching issues early such as scratches, exposed metal, or damaged coatings can prevent further corrosion and costly repairs.

• Inspection Frequency: Inspect 1-4 times a year depending on tree overhang, environmental conditions, and proximity to coastal areas with high salt content. There can also be dynamic factors, such as hazards, exhaust fumes, frequent dust/debris, and farm chaff, not limited to coastal proximity.
• Post Weather Checks: Always inspect after severe weather events such as storms, wind, heavy rain, or hail.

Proper Installation

Proper installation is the foundation of a durable and rust-proof metal roof. 

Having your roof professionally installed reduces the risk of moisture penetration, poor sealing, and improper water drainage, which can all accelerate corrosion.

With the right design and materials, your metal roof will shed water, resist rust and corrosion, and be a long-term investment for your property.

Here are some key points: 

• Professional Expertise: Hire contractors who know how to seal and align metal panels so there are no exposed or vulnerable areas left open to the elements.
• High-Quality Materials: Use top grade metal roofing materials, galvanized steel, aluminum or zinc and make sure they have a durable coating to withstand the elements.
• Manufacturer Guidelines: Follow the manufacturer’s instructions for installation, including correct fastener placement and overlaps to avoid cut edges or water pooling at the wrong angle.

Quality Materials

Using high-quality, corrosion-free roofing materials is key to preventing steel roof rust and ensuring durability. 

Top grade materials will not only extend the life of your roof but reduce the need for repairs. For example, high quality metals like galvanized steel, aluminum and copper have natural or applied coatings that prevent rusting and corrosion even in harsh environments.

• Galvanized Steel: Suitable for most climates as it has a zinc coating for rust resistance.
• Aluminum: Those with an aluminum oxide layer are lightweight and naturally oxidizes so great for coastal areas or high humidity regions.
• Copper: By forming a patina that protects against further corrosion, copper is the premium choice for longevity and looks.

Make sure to choose the right material for your climate. For example, aluminum roofs work well in salt-heavy coastal areas, and zinc roofs in areas prone to acid rain.

Effective Maintenance

Regular maintenance is key to keeping metal roofs in top condition and preventing metal roof rust. With proper care, you can extend the life of your roof and reduce repairs.

• Remove Debris and Dirt: This includes clear leaves, branches and dirt from the roof surface especially after storms or high winds. Focus on gutters and metal panels to prevent moisture and rust in trapped areas.

• Check for Damage: Check for dents, scratches, and cut edges, as these can expose the steel underneath to oxidation. Also, check screws for loosening, which can compromise the roof.

• Repaint or Recoat as Needed: Apply new protective coatings or paint systems to withstand rust and keep corrosion at bay. Consider using advanced coatings like polyvinylidene fluoride (PVDF) for long-term protection and UV resistance.

• Purchase a Maintenance Contract: Have professionals do the regular inspections and maintenance. A maintenance contract promises timely service and prevents forgotten issues. Look for services that include checking the roof’s protective layer, repairing scratched or damaged areas, and evaluating areas prone to corrosion.

Addressing Damage Properly

Scratches, dents, or damage to the protective coating can expose the underlying steel and accelerate the formation of iron oxide (rust). It’s important to fix the small issues before they become big problems that require replacement.

The consequences of ignoring damage include: 

• Leaks: Damaged areas can let water in, and water can seep through and affect insulation, ceilings, and walls.
• Structural Damage: Left unchecked, damage can weaken steel panels and compromise the entire roof’s structure.
• Further Corrosion: One damaged area can spread rust to adjacent metal panels and accelerate the degradation process.

Some proactive steps you can take to mitigate damage include: 

• Inspect for damage after hail or storm and act fast
• Work with a professional roofer to repair cut edges, reapply protective coatings, and seal exposed areas
• Replace severely damaged metal roof panels to prevent the rust from spreading to undamaged areas

What to Do If Your Metal Roof is Leaking

A leaking metal roof can be very damaging if not fixed quickly. Here’s how to fix leaks and get long-term protection for your roof.

Temporary Fixes

For small leaks, temporary fixes can buy you time to prevent water damage in the short term but you need to fix the underlying issue as soon as possible.

You can use: 

• Roof Sealant: Apply roof sealant for metal roofs to cover small cracks or holes. Make sure to clean and dry the area before application to ensure good adhesion.
• Tarps or Plastic Sheeting: If you can’t fix the leak right away, use a tarp or plastic sheeting to cover the damaged area. Secure the tarp tightly so it won’t blow away.
• Proper Materials: Using the wrong materials or wrong application method can cause further damage like trapped moisture that can accelerate rust and corrosion. Use high quality materials and follow instructions carefully.

Professional Repair

Temporary fixes can help, but a professional roofer should be called in ASAP to assess the issue and fix it permanently.

• Qualified Contractors: Look for contractors with metal roof experience as they will know how to identify the source of the leak and fix it.
• Full Assessment: A professional can inspect your roof, assess the damage, and determine if the coatings or individual metal panels need to be replaced.
• Long Term Solutions: Professional repairs can also fix underlying issues like improper installation, poor quality materials, or damage to the protective layer that may not be visible through temporary fixes.

Protect Your Investment with Armour Roof Co.

By knowing the causes of rust and implementing regular inspections, proper installation, and using quality materials, you can extend the life of your new metal roof and protect your investment by making it rust-resistant. 

The short answer is in regular maintenance. Building owners’ prompt action to any damage is key to resisting rust and protecting your property.

Armour Roof Co. can offer advice on keeping your roof intact. Our team serves a wide audience and will provide you with custom solutions for your needs so your metal roof will last.

Get a quote today, book your roof inspection, and we’ll give you the peace of mind you need for long-lasting roofing.