It’s the easiest thing to do next to calling a dependable and well-educated team of roofing contractors in London ON: paint your roof with a rusty metal roof coating. According to its manufacturers, you can inhibit rust and corrosion by using their special anti-rust coating. Is it a deal too good to be true? Truth be told, hundreds of London ON residents find it to be a difficult buying decision — and it’s understandable!

Metal Roof Coatings: Myth or Truth?

As experienced roofing contractors, we’ve seen and are confident about rusty metal roof coating’s capability to improve a metal roof’s long-term lifespan and performance.

You can think of it this way: a roof coating is similar to a glove on your hands. When you’re climbing rock formations or mountains, the glove protects your hands from scratch injuries, improves your grip, and can be the difference between life or death. Rusty metal roof coating works the same way acting as an external layer that protects the steel or aluminum core of your roofing material.

National Coatings is a metal roof coating manufacturer. We can definitely expect them to endorse the positive usage and efficiency of rusty metal roof coatings. However, their statement carries truth below:

Now, back to the question – Do metal roof coatings reduce corrosion on my metal roof? YES! Coatings are excellent at reducing and inhibiting further rust from developing. The RustShield A120 is an excellent primer for metal roofs because it was specifically engineered to combat flash rusting and provide outstanding corrosion protection. (Source)

What About The Galvanized Layers?

It’s confusing to ever need metal roof coatings when galvanized or galvalumed layers SHOULD protect the steel or aluminum core from corrosion. That’s the initial sacrificial layer manufacturers use to preserve metal roof capability and lifespan. However, this coating wears off as the years pass. Most metal roofs will lose their galvanic or galvalumed properties within the last 5-10 years of their lifespan.

According to experts, consistent elemental exposure deteriorates the additional layer. Because zinc and aluminum are not corrosion proof, they will still introduce rust to the core steel or aluminum roof material. However, a layer of rusty metal roof coating helps prolong the rusty metal roof’s performance if it isn’t brittle and still has strength.

Metal Construction News has an excellent explanation of how experts view metal roof coatings (both paint and metal dips) and their long-term effects on roofs.

Joe Marzahl, metal product manager at Anoka, Minn.-based Firestone Building Products sees re-coating materials as a sacrificial layer protecting the material. “As long as they are maintained, panels will not be exposed to elements that cause rusting, and ultimately, panel deterioration,” he says. “Advantages to re-coating a metal roof include long-term life cycle cost savings and a decrease in the volume of construction materials sent to landfills.”

When the metal roof coating is chalking, fading or no longer looks appealing, re-coating can enhance the appearance of the building. A metal roof could be re-coated simply because the owner would like to change the color.

Also, “When a metal roof coating is pealing or there is surface rust, re-coating a roof will increase its longevity by increasing its corrosion resistance,” says Michael Endredi, project engineer at The Garland Co., Cleveland. “Re-coating a roof is a less costly option than re-roofing for scenarios where the roof still functions, but lacks the appeal it once had and is in danger of corroding.” (Source)

Can You DIY It?

It’s easy to paint on your own. While we will never recommend DIY when it comes to metal roof repair and replacements, we are more confident with homeowners who plan to paint their roofs with rusty metal roof coatings. However, we still caution them to take care when they’re above painting the entire roof.

If you’d like to dedicated a few weekends to painting your roof with a rusty metal roof coating, you can use Extreme How-To’s useful guide below.

Before you dive head-long into painting your metal roof you need to determine what type of metal it is, because although it may appear to be galvanized, it may in fact be what is known as terne metal. Terne roofing was made by producing the shingles or roof panels out of one of several different types of base metal and then coating the panel with a mixture of lead and tin. Terne metal has been phased out due to the public outcry about the dangers of lead, even though no specific health threat was ever discovered coming from the use of terne metal roofs.

Terne metal roofs are extremely long-lasting, but because they look very similar to galvanized metal a person can unknowingly invite problems if they use the wrong paint. Galvanized roofs require the use of a different paint than what is used on terne metal. Terne is best painted with an oil-based paint. One of my neighbors used an oil-based paint as a primer, since some of the metal was rusted, and then covered the roof with one of the specially formulated roofing paints that is sold by CalBar for use on old metal roofs for an added layer of protection. However, another neighbor did like myself and only used an oil-based paint. Galvanized steel, on-the-other-hand, cannot be painted with an oil-based or aluminum-based paint. Galvanized metal requires either a zinc-dust type paint or a latex paint.

My house was built circa 1880 and still has its original terne metal roof, which consists of individual metal shingles with an embossed decorative pattern. After many years of exposure to the elements, the paint on the roof began to wear off, crack and peel, necessitating a new paint job. (Read The Rest Here)

It’s important to remember that metal roofs are long-lasting, but still have finite lifespan and performance. A rusty metal roof coating will help prolong its performance and durability, but it holds no promise to being a long-term fix unless you replace the aged and rusted metal roof itself.

If you plan to have your metal roof replaced, make sure you’re working with the finest roofers in London ON, Cub Roofing. We are highly confident we can deliver the caliber of roofing service you need. Contact us today!