Metal Roofing for Denver CO Homes: Corrosion, Rust, and Other Critical Problems

When you have a metal roof, you truly feel unstoppable. It is similar to finding the long-term solution that will make your home last for the longest time possible. However, metal roofs aren't infallible; they have their own sets of problems and challenges. Some unique challenges of metal roofing are corrosion, rusting, and roof leaks -- if you can believe it.

In this article, we'll talk about these metal roof damages, what you can do to prevent them, and make sure you improve its lifespan and durability right from the start.

Do It Yourself has an excellent short guide on preventing steel roofs from rusting. Steel is a strong roofing material. However, left exposed to moisture and rain, steel metal roofing will rust quicker than a coated tin roof. Here is everything you need to know below.

How to Prevent a Tin Roof from Rusting

One of the problems you are likely to encounter with a tin roof is rust. Tin roofs have been around for ages. They have several benefits. They are durable, withstand weather extremities, are resistant to fire, mildew and insects. Besides these attributes, tin roofs are affordable and easy to install. Rust may be your biggest challenge when it comes to maintenance of a tin roof. Rust is created when oxygen and moisture interact. It oxidizes the metal causing it to become weaker. If left unattended, rust can result in serious damage on your roof. In order to prevent the occurrence of rust, follow these 3 preventative measures.


Painting protects your roof from corrosion and rust. Paint your roof with a primer that contains at least 80% zinc. Zinc is an excellent rust preventive. A zinc-rich primer works best if you prepare your roof well before application. This will necessitate a thorough cleaning of the roof to remove all dirt and rust that may have set in.

  • Remove any rust and paint that is peeling off.
  • Use a hand wire brush, disc grinder or sandblaster to get rid of the rust.
  • Wash the roof thoroughly with a detergent and water.
  • Rinse the roof well and allow it to dry completely.

For quicker drying you can wipe away residual water with a rag or old towel. You can then proceed to paint. It is important that you paint on a clean surface. This will prevent dirt from being driven into the tin roofing material as you paint. A clean surface forms an ideal foundation for paint application and is vital to a successful painting job. Paint your roof every 3 years to prevent tin rust from developing.


Elastomeric coatings are an excellent rust preventive. They are an acrylic sealing system that is applied onto the roof in layers. Once it sets it forms an effective barrier on the roof against corrosion and rust. Like with painting, it is important that you clean your roof well before you apply coating. This will ensure a more satisfactory result. Elastomeric coatings are available in various colors. You can enjoy doing a color change to your roof if so desired to give it a new look while extending its durability. A single-layer coating can last up to 5 years. If you do a multiple coating, you need not re-apply for another 10 years.

Galvanized Roofing (Read the full post here)

Some homeowners feel that rusting is preventable if you invest in superior metal roofing material such as aluminum. Indeed, this metal roofing material can last for decades or even a century. In addition, they're lightweight and easier for roofers to handle.

However, aluminum faces a huge problem if left unattended: corrosion. Any Denver CO roofer knows that aluminum corrodes and oxidizes. This process allows it to prevent further internal corrosion that shortens its lifespan and durability. On the other hand, your roof's aesthetics won't be too beautiful when this happens. Below are other damages aluminum metal roofs can face and how you can prevent them.

Does Aluminum Rust?

Aluminum corrodes but it does not rust. Rust refers only to iron and steel corrosion.

Aluminum is actually very prone to corrosion. However, aluminum corrosion is aluminum oxide, a very hard material that actually protects the aluminum from further corrosion. Aluminum oxide corrosion also looks a lot more like aluminum (dull gray to powdery white in color), so it isn't as easy to notice as rusted iron.

When iron corrodes the color changes and it actually expands. This expanding and color change can produce large red flakes that we all know as rust. Unlike aluminum oxide, the expanding and flaking off of rust exposes new metal to further rusting. This is why it is so important to provide a barrier so rust doesn't start.

While aluminium doesn't rust, it often becomes dull from corrosion, and is often encrusted with brake dust, calcium, lime, tarnish, grease, oil and hard water stains. (Read the full post)

Lastly, some chemicals and even the wood on your roof deck can shorten the lifespan of your metal roofing. While it sounds unbelievable, the interaction of certain compositions and substances against your aluminum or steel roof will yield unbelievable damages that shorten the lifespan and long-term durability of your roof.

MBCI has an excellent post on metal roof corrosion, rusting, and other damages that different materials and chemicals cause upon interaction with aluminum or steel roofs. Learn more here.

What to Know About Dissimilar Metals in Metal Roofing Installations

While metal roofing is often used because of its resiliency, strength and longevity, there are circumstances under which corrosion and other reactions can become real issues, to the great detriment of the system’s performance and life cycle. Some basic knowledge and awareness of common causes of galvanic corrosion (also called “electrolytic corrosion”) from the use of certain dissimilar metals, can go a long way in mitigating potential problems.

Lead and Copper with Metal Roofing

Lead and Copper are the biggest culprits when it comes to shortening the service life of metal roofing due to corrosion. It almost goes without saying to make sure these metals don’t come into contact with the roof, specifically roofs with Galvalume Plus products. Here we’ll take a brief look at some of the common problems that can arise.

Due to the high probability of corrosion, it is not advisable to use lead roofing products, such as lead roof jacks for pipe penetrations.

Additionally, graphite, which is the primary material in the common pencil, is extremely corrosive to aluminum and aluminum alloys. Therefore, it is not advisable to write on a metal panel with a graphite pencil. In time, the element will eat through the coating and it will rust out. Eventually, you’ll actually be able to see whatever you wrote on there (that’s not what you want!). Instead, using a Sharpie or a grease pencil will solve the problem with little to no effort.

Copper is another metal that does not react well with galvanized metal panels used in many metal roofing systems. Contact between copper parts and metal roofing can greatly increase the likelihood of corrosion. Some specifics to keep in mind:

Don’t use treated lumber, which has copper in it. Sometimes, an installer will set some type of treated lumber post and place something on top of it. (Read the full post here)

Indeed, all these metal roofing problems may get out of hand if you try to repair them on your own. The best way to get through any metal roofing problem that guarantees a lengthened roof lifespan and durability is to have Denver CO's best metal roof repair and servicing contractor help you out.

Roper Roofing has been servicing Denver CO homes for more than a decade. We guarantee only satisfactory and exemplary results. Contact us today!

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