Metal roofing is a popular choice for home and business owners. It’s durable, lasts a long time, and is incredibly energy efficient. However, no roofing product is immune to experiencing problems. One of the most common issues with metal roofing is rust. Rusted metal roofing has many causes. It’s important to highlight the difference between intentional faux paint finishes and the natural rust accumulating over time.

In this post, Select Renovations will explore the top five causes of rusty metal roofing, common signs, and prevention methods. We’ll also answer some common questions about metal panels. Keep reading to learn more from our roofing experts.

green tile metal roofing without any rust

What is Metal Roofing?

Meta roofing is a roofing system made from metal pieces or tiles. They’re usually known because they’re highly resistant, impermeable, and long-lasting. Metal roofing panels, tiles, and other types are popular in commercial properties but apply to homes all over the Metro Detroit area. The most common types of metal roofing materials include:

  • Steel: Coated with a layer of zinc (galvanized) or a mixture of aluminum and zinc (Galvalume) to prevent rust.
  • Aluminum: Lightweight and naturally resistant to rust, making it ideal for coastal environments.
  • Copper: Known for its durability and attractive appearance, it can develop a green patina over time.
  • Zinc: It offers a long lifespan and is a self-healing property that repairs scratches over time.
  • Tin: Tin roofing is often mixed with lead to make it corrosion-resistant. It’s less common than other roofing materials but still used.
top view of a rusty metal roofing sheet

What Causes Rust on Metal Roofing?

The five most common causes of rust on metal roofing include:

  1. Excess Moisture: Water on metal causes rust, and it’s no different for roofing systems. Rain, snow, and humidity can cause the metal to oxidize, which leads to rust formation. It’s a common problem in places with heavy rain or coastal areas where the air has saltwater.
  2. Chemical Reactions: Rust stains result from a chemical reaction between iron, oxygen, and water, known as oxidation. This process can be sped up by contaminants in the air, such as sulfur dioxide, which is common in industrial areas.
  3. Environmental Factors: Saltwater from coastal places and industrial pollution accelerate the rusting process. Saltwater, in particular, can corrode metal faster, leading to quick decay.
  4. Physical Damage: Scratches, dents, and other damages to the metal roof can expose the underlying metal to moisture and air, speeding up the corrosion process. Hailstorms, falling branches, or even foot traffic on the roof can be causes.
  5. Poor Maintenance: Neglecting your roof allows small issues to become significant. Leaves, debris, and standing water can create a rust-friendly environment. Regular cleaning and inspections are necessary to prevent rust from forming.
Roofer painting the surface of a sheet of Galvanized Iron roof with rust-inhibiting red oxide primer

Faux Rust Paint Finishes vs. Natural Rust

It’s important to differentiate between faux rust paint finishes and natural rust. Faux rust finishes are intentionally applied for aesthetics, giving a rustic look without compromising the metal underneath. On the other hand, natural rust means oxidation and deterioration, which can weaken the roof and lead to leaks and other damage.

corrugated metal roofing sheet close up

Common Signs of Rust on Metal Roofing

Pinpointing rust early can help prevent extensive damage. Here are some common signs to look out for:

  • Color Changes: Rust typically starts as small brown or reddish spots and can spread across the surface of the metal.
  • Flaking and Peeling: As rust progresses, it can cause the metal to flake and peel away.
  • Leaks and Water Damage: Rust can create holes in the metal, leading to leaks and water damage inside the building.
  • Weakening Structure: Rust can compromise the roof’s structure over time, making it weaker and more prone to damage.
Rusty roof made of corrugated sheet, aerial view

Preventing Rust on Metal Roofing

The pillar of preventing rust on metal roofing involves regular roofing inspections. Select Renovations advises our customers to inspect their roofing at least once a year, twice if possible, during Spring and Fall. Preparing your roof for situations that may lead to corrosion is the best way to protect it. However, there are other protective measures:

  • Make sure that your metal roof is installed properly. If a professional installs it correctly, it will minimize the risk of scratches, dents, and improper sealing.
  • Apply a protective coating, such as galvanization or painting. This creates a barrier between the metal and the elements. Reapply it when necessary.
  • Clean the roof. Remove leaves, debris, and standing water.
  • Inspect your roof for damage. Check for scratches, dents, and worn coating, and call your local roofer if needed.
  • Choose rust-resistant materials. Aluminum or zinc works especially well for this.
Galvalume roofing mild steel is anti-rust and durable

Answering Your Metal Roofing Questions

Can a rusted metal roof be repaired?

Yes, a rusted metal roof can be repaired, but it depends on how extensive the damage is. DIY methods, such as rust removers and sanding, can be effective for minor rust. For extensive damage, it’s best to consult a professional who can replace severely damaged sections.

Can I paint over a rusted metal roof?

Painting over a rusted metal roof is possible but requires preparation. The rust must be removed, and the surface should be cleaned thoroughly.

Are metal roofs supposed to rust?

While metal roofs are designed to resist rust, they can still rust under certain conditions. Factors such as improper installation, exposure to weather, and lack of maintenance can cause rust formation.

How do you stop rust on a metal roof?

There are many methods to stop rust from forming, including:

  • Remove debris, dirt, and any loose rust.
  • Use a rust remover to eliminate existing rust.
  • Sand the area to create a smooth surface.
  • Use a metal primer to prepare the surface for painting.
  • Apply a protective coating or paint to prevent future rust.
3 upscale homes with metal roofs, aerial view


Rusted metal roofing can be an important issue, but with preventive measures and regular maintenance, you can keep your roof in great condition. By addressing the causes of rust and applying long-term solutions, you can extend the lifespan of your metal roof.

If you have any concerns about rust on your metal roof, don’t hesitate to contact a professional for advice and assistance. Call Select Renovations today if you’re having trouble with rust on your metal roofing!