Many homeowners and project stakeholders feel disappointed when metal roofs that were installed only 1–2 years ago begin to show signs of rust. At the time of purchase, these products are often claimed to have high durability and to be suitable for long-term use.

The question is, why does this happen?

And is metal roofing really “that bad,” or are there other factors that are often overlooked?

This article will discuss the main causes of why metal roofs rust quickly, while also explaining why high-quality metal roofs such as those used by COMET can withstand rust and corrosion for up to 10 years.

Common Causes of Metal Roofs Rusting Quickly

1. Low-Quality Base Material

Not all metal roofs are made from the same base material. Some products use steel with lower standards, which is naturally more susceptible to oxidation. When the base material itself is weak, no protective layer will work optimally. Rust is simply a matter of time.

2. Thin or Inconsistent Coating

The protective layer (coating) is the main defense of a metal roof against rust and corrosion. Unfortunately, many products on the market use coatings that are too thin or uneven in order to reduce costs.

As a result:

• Protection deteriorates quickly
• The surface is easily exposed to water and air
• Rust begins to appear from small points that often go unnoticed

3. Coating Not Designed for Tropical Climates

Indonesia has high humidity levels and extreme rainfall. If the coating is not designed for these conditions, its protection will degrade much faster than what is claimed on paper.

4. Micro Damage During Production or Installation

Small scratches, impacts, or imprecise bending can damage the protective layer. From these points, rust usually begins to spread, even though the roof may look “perfectly fine” from a distance.

Why Can COMET Metal Roofs Withstand Up to 10 Years of Rust & Corrosion?

At COMET, the durability of metal roofing does not depend on just one factor. Long-term performance is built from a combination of guaranteed base materials and a high-quality coating system.

1. Base Materials with High Quality Standards

All COMET metal roofs use base materials that have gone through a strict selection process. These materials have strong structural integrity and natural resistance to oxidation, making them less reactive to environmental conditions.

This means that even before the coating is applied, the base material already has a solid foundation.

2. High-Quality and Tested Coating

COMET uses coating systems that are designed to:

-Withstand exposure to water and high humidity

-Significantly slow down the corrosion process

-This coating is applied consistently across the entire surface, ensuring there are no weak areas that could easily become starting points for rust.

3. A Protection System, Not Just a Layer

In many products, coating is merely a “protective paint.” At COMET, coating is part of a comprehensive protection system that works together with the base material, roof profile, and production standards.

This is why all COMET metal roofs are designed to have resistance of up to 10–20 years against rust and corrosion.

Rust on Roofs Is Not Just a Visual Issue

A rusted roof is not only about appearance. In the long run, rust can lead to:

• Reduced structural strength
• Potential leaks
• Repair and replacement costs that are far more expensive

Therefore, choosing a metal roof should not be based solely on price per sheet, but on long-term durability and the quality of the overall system. If metal roofs typically rust within 1–2 years, the problem almost always comes back to the quality of the base material and the coating used.

COMET is here as a solution, with high-quality material and coating standards designed to withstand tropical climate conditions and long-term use. With the right protection system, metal roofs should not rust quickly—and at COMET, durability of up to 10-20 years is not just a claim, but the result of consistent quality.

Choosing a high quality metal roof today means avoiding major problems in the future.