Rusting metal roofs: The hidden threat to your commercial investment

By Armour Roof Co. 

Ignoring rust could cost you big, but these expert-backed strategies will protect your roof and your budget. 

A rusting metal roof isn’t just a cosmetic issue — it’s a ticking time bomb for your commercial or industrial building. Rust signals more than just surface decay; it’s a warning that your investment is at risk. Left unchecked, it can quietly undermine the structural integrity of your roof, leading to staggering replacement costs and potential safety hazards. The good news? With a proactive approach and the right know-how, you can save thousands and extend the life of your roof by years. Buckle up, because here at Armour Roof Co. we explain how to turn rust from a liability into a solvable problem. 

1 - Why metal roofs rust & why you should care 

Let us be clear - Rust isn’t just an eyesore, but an indicator that your roof is in need of attention. In fact, we’ve inspected over 300 metal roofs, and the Journal of Building Physics says that rust can reduce the lifespan of a roof by 15%-20%. Crazy, right? 

But here’s the good news: Catching rust early can save you thousands in replacement costs. 

2 -The 5-step rust busting protocol 

Now for the meat and potatoes: Here’s exactly what to do when you spot rust on your metal roof. 

Step 1: Assessment 

In order to know what to do, you need to accurately assess the current state of your roof. Pro Tip: Use our RUST scale to assess severity: 

• R – Reddish discoloration 
• U – Uneven surface 
• S – Scaling or flaking 
• T – Thoroughly compromised 

Step 2: Cleaning 

Cleaning is often overlooked, however, 90% of DIY rust removal fails because people skip proper cleaning. Don’t be one of them. Bottom line: Clean first, treat second. 

What to do instead: 

1. Remove loose debris 
2. Apply a specialized metal cleaner 
3. Scrub gently with a soft-bristled brush 
4. Rinse thoroughly 

Bottom line: Clean first, treat second. 

Step 3: Rust removal 

Now, this is important: Your approach depends on the severity of rust. 

For light rust: 

• Use a wire brush 
• Apply naval jelly 
• Wait 10 minutes 
• Wipe clean 

For heavy rust: 

• Consider calling a professional commercial roofing contractor or industrial roofing contractor 
• Use mechanical methods (sanders, grinders) 
• Apply rust converter 

Step 4: Prime and paint 

Most people don’t realize how important it is to prime and paint. Because proper priming can extend your roof’s life by 15 years.The best primers contain: 

• Zinc chromate 
• Iron oxide 
• Zinc phosphate 

As for paint, choose from these options:  High-quality metal roof paint, UV-resistant coating and avoid generic exterior paint 

Step 5: Prevention 

The best defense is a good offense; therefore, prevention is key. Our data shows that preventive maintenance can: 

• Reduce rust occurrence by 75% 
• Save $3,000+ in repairs 
• Extend roof life by 20+ years 

3 - Advanced rust prevention techniques 

Want to take your rust prevention to the next level? Try these pro strategies: 

1. Bi-annual inspections  
2. Zinc strips installation 
3. Professional coating every 5 years 
4. Proper ventilation 

Armour Roof Co. offers bi-annual inspections, and we can coat areas that are showing vulnerabilities. 

The bottom line 

A rusting metal roof isn’t a death sentence for your commercial building; however, it does require prompt action. If you’re unsure about climbing on your commercial or industrial roof to assess the rust damage, consider finding a reputable commercial roofer that can do it. 

Original article source: Armour Roof Co.