How To Paint A Rusty Metal Roof [4 Steps To Follow]

Metal roofs are the most durable coverage for your home. You can style it to look like wood, clay, or even stone. But it’s prone to oxidation and rust, which makes it lose all its beauty.

So, how to paint a rusty metal roof properly?

To paint a rusty metal roof first you have to get rid of the rust. Use TSP to get the rust and staining off the metal. Then use a vinegar coating on the metal surface. After that, apply primer to make the metal rust-proof. Finally, apply paint to your metal roof.

That was the preview. If you want to know more, stick with us till the end. We’ve got you a step-by-step guideline for the whole process and It is also a good idea to read up on how to paint dormers on a steep roof for a home.

So, let’s jump right in-

Can You Paint A Rusty Metal Roof?

Rust can make your once beautiful metal roof look dirty and haggard. New roofing can cause you a hefty amount of sum. Instead of throwing it away, it’s better to give it a new look.

So, the first thing that comes to mind is painting the roof. Surely, you can paint your roof to make it beautiful again. But it comes with many steps when the roof is rusted. 

Leaving the painting process to a professional will definitely ensure the desired outcome. But it’s gonna cost you a lot as well.

If you have a DIY mindset, you can do the whole thing yourself. it’s going to save you a lot of money as well.

How To Paint Rusted Galvanized Metal Roof?

Painting a metal roof comes with some extra steps that are absolutely necessary. You can’t skip these steps as they prepare the base for painting. The process is the same for painting how to paint a rusty tin roof.

Step-1: Get Rid Of The Rust From Metal Roof

The first thing you need to do is to get rid of the rust. There are two methods of removing rust from metal. Both of them involve physical work. But don’t worry, it’s not that hard. 

Before we begin, get rid of the big flakes from the roof. You can use a sturdy brush to scrub off the rust. It won’t get rid of all the rust. But it will reduce the rust by a good amount. Once you’re done, you can pick any of these two methods described below-

Method-1: Remove Rust Using Trisodium Phosphate

Trisodium Phosphate is a chemical compound that removes rust from metal. It gets rid of metallic stains and prevents rust from growing further. It’s super effective against rust. However, it should be dealt with caution. 

TSP can cause eye injury and skin irritation. So, make sure you’re wearing protective clothes before using them. Use rubber gloves and eye goggles too.

To apply TSP, first, you’ll have to make the solution. It comes in powdered form. Mix the powder with water. The ratio for the solution is 1 cup of TSP per gallon of water.

If the mixture is ready, apply it to the rusty areas. Use a sprayer to spray it evenly on the metal surface. 

Wait for 10 to 15 minutes so that it saturates the surface properly. Giving it enough time will weaken the rust. It’s also highly effective against mold and mildew. 

Now, grab a hard bristle scrub brush and start scrubbing the rust away. It will remove most of the rust and stains.

Method-2: Using A Pressure Washer To Remove Rust

This method will save you time and a lot of physical work. All you’re gonna need is a pressure washer. In case you haven’t used it before it’s best to not do it by yourself.

Anyway, to use it, set the pressure washer at 2500 PSI. Then start spraying the metal roof. This way you’ll be able to remove most of the flakes and rusts at this pressure. 

This method will also get rid of any existing mold and mildew. Lastly, try to get rid of as much of the oxidization as you can.

Extra Tip: Combination Of Both Methods

Both of the methods above are useful when it comes to removing rust. But if you combine them, you’ll have more chances of removing them. 

Thus, first, apply trisodium phosphate on the metal roof. Leave it for 15 minutes and set the pressure washer to 2500 PSI. 

Now, start spraying it on the surface. With this, you won’t have to manually scrub off the rust yourself. The machine and the chemical will do the job.

Step-2: Use Vinegar To Prevent Rust

Before we paint on the rusted galvanized metal roof, we’ve to coat it with vinegar. Use white vinegar for this process. It’s pretty much available and inexpensive. It will be very effective for the best paint for galvanized metal roof.

The galvanized metal roofs are coated with zinc layers which inhibits rust. Sadly, this coating fails over time leading to rusts on the metal. To prevent the rust from resurfacing again we’re going to use vinegar. The acetic acid in vinegar neutralizes zinc thus preventing rust.

So, take a rag and apply some white vinegar to it. Now, wipe the metal roof with the rag. No need to scrub the metal surface. Just gently wipe off the whole area. 

This step is going to protect the metal from corrosion. It will help the paint to stick on it as well.

Step-3: Apply Primer On The Metal Roof

Before you paint the metal roof, it’s important to use primer on it. Using a water-based rust-inhibitive primer will increase the longevity of the metal roof. Also, it prevents rust and makes the roof waterproof. 

If you have your primer, let’s start applying it on the roof. But before that read all the manufacturer guidelines of the primer. You’ll get full instructions on how to apply it to the metal.

You can apply the primer with a paint roller or a sprayer. Using a paintbrush will be too slow unless you have a small roof. Apply it evenly on the whole surface. Do not miss any spots.

When applying the primer, keep in mind that you can’t walk there. It has to dry before you can walk in that area again. 

So, paint it keeping your ladder in the front. This way you can come back down after you’re done. Lastly, let it sit for a day or two before you start painting it.

Step-4: Apply Paint On The Metal Roof

It’s finally time to paint the metal roof. You can choose any standard exterior paint since your roof is now rustproof. But to be on the safe side, use rust-preventing paint. It’ll make sure that your roof won’t be needing another paint anytime soon.

Now, thoroughly check your roof to see if the primer has dried properly. You can’t apply paint on the roof until it dries off. Once you’re sure that the primer has cured completely, you can start painting.

Here is the best paint for rusty metal roof: Rust-Oleum Rusty Metal Primer.

The painting process is the same as applying primer. You can use a paintbrush for painting. But it’ll take a lot of time to paint the whole roof. Thus, it’s better to use a sprayer or how to paint a metal roof with a roller for this project.

Apply the paint evenly on the surface. Make sure it’s not getting a thicker or thinner coat around the places. Because it’ll likely show the difference in sunlight reflection. Now, wait 24-48 hours for the paint to cure completely on the surface.

You’re almost done!

Just take a closer look at the painted surface. Sometimes, you’ll find darker or lighter spots all around. It happens when the paint was applied less or more heavily to some areas.

If you have a similar issue, apply another coat of paint to the roof. Repeat the painting process and let it cure for a day. And now, you’re finally done with painting your once rusted metal roof. Hopefully, you’ve gotten a satisfactory result.

Extra Tip

Check the weather before you apply paint on your metal roof. If the painted coat gets wet from rain it’ll ruin all your efforts. Not to mention, it’s going to leave a huge mess of paints. You’ll have no choice but to redo a lot of things.

Also, follow the safety measurements while using an extension ladder. Always read the safety guide located on the ladder before using it.

FAQs

Question: Can I paint galvanized metal roof without priming it?

Answer: No, you can’t. Primer is a necessary element that strengthens the paint on the metal. Also, it prevents rust. If you paint on an unprimed metal roof, it’ll keep peeling off.

Question: Can I use an ordinary primer on the galvanized rusted roof?

Answer: No, you shouldn’t. Ordinary primers are not rust-proof. If you use an ordinary primer there will be an occurrence of new rust.

Question: How to paint a steel roof?

Answer: Steel roof represents the basic metal roofing system. They are zinc coated such as the galvanized metal roof. The process of painting a steel roof is the same as painting a metal roof. Just follow the instructions above to paint your steel roof.

Here is a nice video on how to paint a tin roof.

Conclusion

Now you know how to Paint a Rusty Metal Roof. Hopefully, you’ll be able to give your roof a perfect new look.

Good luck with the steps on how to clean a steep metal roof.

That’s all for today. Stay happy, stay safe.