Q&A – Looking for a way to prevent rusting

This homeowner was looking to extend their roof's lifespan and came to our experts with some questions.

Kevin, a homeowner in Virginia, was working on a standing seam metal roof and had a question about handling rust. This is what they asked: 

Standing seam metal roof needs to be re-coated. There is some surface rust, which I will remove with wire brush, and small pinholes which I will seal with appropriate sealant. Which is the better option to extend the life of the roof and prevent further rusting?

1. Fibered aluminum coating
2. High performance metal primer (Benjamin Moore HP100 or HP1320) and acrylic paint

This is what one of our roofing experts, John Kenney of Cotney Consulting Group, had to tell Kevin about his question: 

Kevin, you’re on the right track by removing rust and sealing pinholes before recoating. The primer-and-acrylic system is the better long-term solution between the two options you listed.

Fibered aluminum coatings are inexpensive and reflective, but they don’t bond as well to bare metal, and rust often creeps back underneath. They also tend to chalk and dry out, which means recoating every few years. They’re more of a short-term patch than a lasting system.

By contrast, a high-performance metal primer followed by an acrylic elastomeric topcoat creates a layered, durable protection. The primer locks down residual oxidation, while the acrylic coating resists UV, stays flexible and is easier to maintain. Applied at the right thickness, this approach can extend your roof life by a decade or more with only periodic maintenance recoats.

Preparation remains key: Clean rust thoroughly, seal seams and pinholes with a compatible sealant and apply primer and coating at the manufacturer’s recommended coverage rates. For best results, do the work in dry, moderate weather.
The bottom line is that if your goal is true life extension rather than a quick fix, the primer plus acrylic system is worth the investment.

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