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Metal roofs are common on commercial buildings and are increasingly being used on residential properties as well. That’s because of their many advantages, such as longevity, energy efficiency, and resistance to extreme weather.
And while metal roofs are relatively low maintenance, they can develop problems over time, especially if routine inspections are overlooked. One of the most common issues is rust. Left untreated, rust can weaken the surface, cause leaks, and shorten the life of the roof.
Understanding what causes rust and how to safely remove it is key to keeping your metal roof in good shape for years to come.
What Causes Rust on a Metal Roof?
Rust forms when the protective coating on a metal roof becomes compromised, allowing moisture and oxygen to reach the underlying steel or iron. Over time, this exposure leads to oxidation, which appears as reddish-brown patches or streaks.
Several factors can increase the likelihood of rust developing:
- Scratches or damage to the paint or coating, often caused during installation or by falling debris
- Standing water from clogged gutters, poor drainage, or roof design issues
- Salt in the air, which is especially common in coastal areas of Florida
- Lack of regular maintenance, including inspections that could catch small issues before they worsen
Identifying rust early is essential. Catching it before it penetrates the metal can make all the difference in how extensive (and expensive) the repairs will be.
How to Identify Rust Early
Metal roofing has come a long way from the old-fashioned “tin” roofs that once topped barns and sheds. Today’s metal roofs are typically made from galvanized steel, aluminum, or other treated metals designed to resist corrosion. Most are coated with specialized paint or sealants that offer strong protection from the elements. As a result, newer metal roofs are much less prone to rust than older versions, though they are not entirely immune.
Rust can still develop if the protective coating is scratched, worn away, or compromised over time. This is especially true in areas with high humidity, salty air, or where leaves and debris tend to collect.
Homeowners should look for early warning signs like:
- Discoloration or reddish-brown stains on panels or seams
- Flaking or bubbling paint
- Small pits or rough patches on the surface
- Water stains or corrosion around fasteners or flashing
These signs often appear in less visible areas, such as roof edges, around vents, or in places where water tends to pool. Regular roof inspections, especially after storms or high winds, can help catch problems early and prevent them from spreading.
Steps to Remove Rust from a Metal Roof
Removing rust from a metal roof is a process that takes time, care, and the right materials. If caught early, small rust patches can often be treated without the need for major repairs.
Here’s how to do it safely and effectively:
- Prioritize Safety
Before climbing onto your roof, make sure you have the right safety gear. That includes a sturdy ladder, non-slip shoes, gloves, and eye protection. If the roof is steep, wet, or in poor condition, it’s best to leave the job to a professional. - Clean the Area
Start by removing any debris, dirt, or loose rust using a broom, wire brush, or pressure washer. A clean surface ensures that the rust removal products can do their job. - Apply a Rust Remover or Rust Converter
Use a rust remover specifically designed for metal roofing. Follow the manufacturer’s instructions carefully. For deeper corrosion, a rust converter may be a better choice. These products chemically change rust into a stable, paintable surface. - Rinse and Allow to Dry
Once the rust has been treated, rinse the area thoroughly with water to remove any residue. Let it dry completely before moving on to the next step. - Prime and Paint the Surface
Apply a high-quality metal primer to seal the area and prevent future corrosion. Once the primer has dried, repaint with a roofing-grade paint that matches your roof’s color and provides additional protection.
When to Call a Professional
While small rust spots can often be handled by a homeowner with the right tools and precautions, there are times when it’s smarter and safer to bring in a professional roofing company.
You should consider professional help if:
- The rusted areas are widespread or cover multiple sections of the roof
- Rust has already caused visible holes, soft spots, or leaks
- The roof is steep, slippery, or difficult to access safely
- You’re unsure about the condition of the roof’s underlying structure
- Previous attempts to treat the rust haven’t stopped it from spreading
Professional roofers have the training, safety equipment, and materials to address rust correctly and completely. They can also inspect the roof for hidden issues that might not be visible from the surface, such as water damage beneath the panels or corrosion around fasteners.
In many cases, having a professional handle the job can save time, reduce risk, and even extend the life of your roof.
How to Prevent Rust from Coming Back
Once rust has been removed, ongoing maintenance is the best way to keep it from returning. Even in Florida’s humid climate, a well-maintained metal roof can last decades without significant corrosion.
Here are a few preventative steps that can make a big difference:
- Clean your roof regularly. Remove leaves, branches, and debris that can trap moisture and cause rust to form underneath.
- Inspect after storms. High winds and falling branches can scratch the protective coating or dislodge fasteners. Addressing damage early helps prevent rust from developing.
- Keep gutters and downspouts clear. Clogged gutters can lead to standing water along roof edges, which increases the risk of corrosion.
- Touch up paint and sealants as needed. If you spot chips, flakes, or scratches in the roof coating, patch them with compatible paint or sealant to restore the protective barrier.
- Consider protective coatings. In high-risk areas, such as coastal zones or heavily shaded roofs, a professional application of a corrosion-resistant coating can offer added protection.
Preventative care doesn’t have to be time-consuming or costly, but it can go a long way toward preserving the look and performance of your metal roof.
Your Trusted Lakeland Roofers
Metal roofing is known for its durability, but that doesn’t mean it’s immune to problems. If you’ve spotted rust or want a professional opinion, Lakeland-based Stronghold Roofing & Solar can help.
Our experienced team provides inspections, maintenance, and repairs that keep your roof looking and performing its best. Serving homeowners across Florida, we’re here to make sure your roof stands up to the elements for years to come.
Contact us today for a free roof estimate!
FAQs – Rust On Metal Roofs
How long do metal roofs last before they start to rust?
With proper installation and maintenance, most metal roofs can last 40 to 70 years. Rust may appear sooner if the protective coating is damaged or if the roof is in a high-moisture environment.
Can I paint over rust on a metal roof?
You should never paint directly over rust. The rust must be cleaned and treated with a rust converter or primer before applying paint, or the problem will continue underneath.
Are certain types of metal roofing more rust-resistant than others?
Yes. Aluminum roofs are naturally resistant to rust, while galvanized and galvalume steel offer strong protection due to their zinc or aluminum coatings.
Is rust on a metal roof always a serious problem?
Not necessarily. If caught early, surface rust can often be removed and sealed without long-term damage. However, if left untreated, it can lead to leaks and structural issues.
How often should I inspect my metal roof for rust?
Twice a year is ideal—once in the spring and once in the fall. You should also inspect it after major storms or high winds.
