Is Painting a Rusted Metal Roof a Good Idea?

Is Painting a Rusted Metal Roof a Good Idea? (DIY Guide Included)

Do you live in a house with a rusty metal roof or have a shed that has unsightly rust on the roof? Are you tired of having to looking at it continually spread and maybe even spend hundreds of dollars every year to fix leaks and rust problems?

In this article, we will cover painting a rusty metal roof using only common household items and painting supplies. We will also go over the pros and cons of painting a rusty metal roof and include some of the things you should look out for.

Painting Rusty Metal Roofing

If you are looking to save money and get a new look for your home or building, then read on. This guide will teach you everything you need to know to for painting a rusted metal roof yourself.

The Causes of a Metal Roof Rusting

Metal roofs are beautiful, durable, and long lasting, but unfortunately, they can also be prone to corrosion and ultimately rust. Rust stains are unsightly and can ruin the appearance of your home or building. Fortunately, there are several things you can do to prevent rust from forming on your home’s roof in the first place.

Apply a protective coating to your roof every three years can help to prevent rust. This will help protect against moisture and prevent rust from forming. What happens most times when a metal roof starts to rust is this protective coating is gone and the bare metal is exposed.

The protective coating on many of the metal roofing today is either paint or a galvanized layer (zinc). When the protective coating is gone oxygen reacts with the metal and oxidization occurs which results in rust forming on the metal roof. Painting a rusted metal roof can give it that protective coating again, but prepping the metal roof needs to be done first.

Once Rusting Has Started it Will Likely Spread

Sheet metal roofs aren’t cheap, but they can last a very long time. Depending on the type of roof you choose and the quality of the roofing materials, you could potentially have a roof that can last for 50 years or more. However, once the roof starts to rust, it’s time to take action as the rust will continually spread throughout the roof.

Corrugated and Standing Seam Metal Roofing

There are two main types of sheet metal roofs: corrugated metal roofs and standing seam metal roofs. Corrugated roofs are flat sheets of metal that are bent into a series of waves which are more common on homes and small buildings. Standing seams are thicker pieces of metal that are welded together to form a continuous piece and used more in commercial applications. Both types of roofs look similar, but each offers different benefits and their lifespan can differ greatly.

Corrugated roofs are typically cheaper to install, but they tend to require more maintenance and are of a lesser quality and thickness. Standing seams are much easier to maintain, but they cost more upfront. Either option is worth considering depending on your budget and needs.

Regardless of the type of roof you decide on, you’ll want to inspect it regularly to make sure that it hasn’t rusted. Rust stains the metal and causes it to lose strength. Once you notice signs of rust, painting a rusted metal roof with a sealant to prevent further damage.

To avoid having to replace your roof entirely, you might consider painting it instead. Painting a rusty metal roof gives it a nice, clean finish while maintaining its durability. While it’s possible to paint a roof yourself, professional painters can usually complete the job faster and more efficiently.

Simply Painting a Rusted Metal Roof Is Not The Answer

One of the biggest problems that happens when someone attempts to paint a rusted metal roof is they don’t clean the roof surface for painting properly. It’s like getting your car painted and not even taking it for a wash first. You’ll need to take some time and prep the roofing for paint and remove the metal rust on the existing roof. One thing that you’ll certainly want to do is clean the roof and remove as much of the rust as possible.

Step 1: Cleaning the Roof

The best way to clean a metal roof that you are planning on painting is with a pressure washer. If you only plan on painting a small area on the roof you may not want to use a pressure washer as it can sometimes blast away paint and other protective coatings on the roof itself.

Most roofing will have dust and debris which can cause sealants and paint to not stick properly. A pressure washer is a great way to blast away this dirt and debris to prepare the roof before painting. A good proper roof cleaning is a must. Then you can work on getting the rusted metal surfaces down on the roof as well.

Step 2: Removing the Loose Rust from the Roof with a Wire Brush

While removing all of the rust from your roof and getting the metal back down to where the oxidization has not started is recommended it’s not always an option. If the rust is widespread already on your roof you want to consider new roof panels or using a wire brush to take off as much of the rust as you can before painting it. Here is one option for a wire brush which can make the process easier pictured below:

Step 3: Once The Surface Rust is Removed The Prep is Done, Almost

Now that you have the roof cleaned and rust removed, it’s a good idea to give it another clean to remove any of the rust dust that may be present. After that, you’re ready to start painting a rusted metal roof with a sealant or paint.

There are several different types of sealants that are on the market today and choosing can mean the difference between priming or not. For most cases, if you plan on using paint for the roof then you’ll want to use a good primer first. Here is one primer that is available on Amazon:

Of course, if you’re using a sealant such as elastomeric coating you likely won’t need a primer. Check with the paint or sealant you plan on using for your rusted metal roof to determine if any additional items are needed. Some paints may also need several coats when used whereas sealants may not.

If you only have a small area on your roof that is rusted you can use spray cans to repair those areas. You’ll still need to properly clean the area and remove the old rust. Be careful to match the paint coat for the new area with the old area. A paint sprayer can sometimes help to blend this area as well. If you are planning on painting an entire roof, spray cans are obviously not the answer and you should opt for a more powerful paint sprayer or roller setup for your rusted roof project.

So What Happens if you Just Paint Over The Rusty Metal Roof?

Simply painting a rusted metal roof is a common practice, especially since it’s relatively inexpensive. But while it might seem like a quick fix, painting over rusted roof surfaces could lead to problems down the road and the end product won’t turn out like you probably hoped.

For starters, paint applied directly to a rusty surface can create a layer of corrosion underneath which can trap moisture and let the rust spread. This corrosion can also lead to leaks and other damage on the roof. And if you’re planning to sell your home in the future, you may run into trouble trying to resell it if the roof needs extensive repairs if it’s found during a home inspection.

There are several different types of paints available, each with varying levels of effectiveness for painting a rusted metal roof. Some contain zinc oxide, which can prevent rust from forming in the first place. Others contain copper sulfate, which can remove existing rust. Still others contain chromium, which can protect against further rust formation.

Painting Rusted Galvanized Metal Roofing

While must of the metal roofing sold today is actually painted metal there are some metal roofing which is still galvanized. When the roofing is galvanized it has a protective layer of zinc on the roof panels which effectively stop the metal from rusting. This layer also makes it appear as a shiny metal which is hard to duplicate with metal roof paints. If you have a galvanized roof you can still paint it just like a standard painted metal roof it just may not look the same as it did before with a metal surface appearance.

Should Metal Roofs be Painted?

Metal roofs are durable, long lasting, and beautiful, but they can become rusted over time. Fortunately, there are several options available to restore damaged metal roof surfaces.

One option is to paint the roof with a primer coat followed by two coats of color. Another option is to apply a protective coating to prevent rusting. Both methods may require professional assistance, however, and neither method is suitable for every situation.

Paint for Galvanized Metal Roof

If you want to keep the appearance of your galvanized steel roof but still want to protect it from rusting there are options which can help. One popular type of paint or sealant option is to use a roof coating that many mobile home owners use. It’s referred to as ‘kool seal’ but it is in fact, just the brand that is often used. This type of roof coating can work on most metal surfaces including corrugated metal roofs. Here is one option for Kool Seal roof coating:

How Much Does it Cost to Get a Rusty Metal Roof Painted?

One of the biggest challenges of painting metal roof surfaces is ensuring that the coat of paint adheres properly. And that means removing as much of the rust as possible which can vary greatly depending on the size of the roof itself and the area that is already rusted.

As a do it yourself project, labor may not be taken into account as you are planning on completing the project yourself but if you choose to get a contractor to handle the roof service for you this can be a huge factor in pricing especially if you need the entire roof cleaned, rust removed, and sealed.

The other expenses will depend on the type of protective coating you have and any additional components that may be needed. You’ll also need to consider tools such as a paint sprayer, cost of paint, and dry cloths and such to protect other areas of your home from the paint job.

It May Be Less Expensive to Get a Roof Replacement

If the extent of damage on your old roof is too much, painting a rusted metal roof may not be the best option. It may be cheaper to have the metal roof replaced instead.

If you would like a free quote on painting your home’s roof or replacing your metal roof be sure to fill in the form below to get free quotes from qualified, local roof contractors in your area and start enjoying a beautiful metal roof on your home.

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