Rust on metal roofs is one of the biggest challenges for homeowners. It not only makes the house look unappealing but also results in costly repairs in the long-term.

You can easily paint over your rusted metal roof as long as you give it a quick coat of rust converter first to get rid of rust and prevent it from returning. If done right, treating the rust and giving your metal roof a lick of paint will extend it’s life and dramatically improve its aesthetics.

Think of roof paint like gloves when rock climbing. They protect your hands from scratches and injuries and give you the grip to hold on to the top. Roof coatings protect the aluminum or steel roofs from corrosion (rust).

Anti-rust paints with rust-retardant primer. For a rusted roof, the regular paints alone can’t prevent rust from spreading. You need to combine your paints with a good primer. Acrylic acid paint is one of the most popular paints for roofs.

A Primer improves the paint’s adhesion on the metal roof and forms an impenetrable coating to ensure rust doesn’t bleed through the paint.

It is usually applied as the first coating, and once it dries, a water-based paint follows as the second coating.

Keep in mind, your choice of paint should coordinate well with the primer for best results. A good idea is to use a paint and primer from the same manufacturer.

What kind of paint do you use on a rusty metal roof red roof

Should I treat rust before painting?

Yes! While painting over rust is a good way to prevent rusting on your roof, it doesn’t stop the rust that is already eating up your roof. You first need to prepare the roof surface and clean it back to a smooth, shiny metal before you begin painting.

If the rust covers only a small portion of your roof, use sandpaper to remove it. If it’s big, use a handheld drill with a wheel wire brush. Next, wash the affected area with detergent and hand brush, then dry it immediately with a dry cloth.

You can also use a rust-removal product for persistent spots. Once this is complete, you can now apply the primer and paint on your roof.

faq pro paint the roof

Are there paints with rust converters in them?

No! Most manufacturers prefer to produce paints and rust converters separately as they work more efficiently individually. Homeowners can choose to paint their roof after applying a rush converter – but it’s not compulsory.

Most paint manufacturers have, however, been able to manufacture a 2 in 1 paint known as Paint Primers, which combine paints with primers.

Will the metal continue to rust under the paint?

Yes! If you only paint over the rust without first cleaning the roof surface, you’re essentially masking it and not removing it. The rust will continue to spread and compromise the integrity of your roof. The longer you’ll take to address the issue, the more prevalent the rust will be. This is why it’s crucial to use rust removers and wire brushes to clean your metal roof before painting.

Can I paint over a rusted metal roof paint rusted metal

How to treat rust before painting

For you to succeed at painting over rust, you have to first prepare your roof surface. Do this by cleaning and clearing the rust from your roof surface. Some of the things you’ll need include:

Wire brush

Wire brush rusted metal roof

A wire brush is the most important tool you’ll need for your first step. Use it to remove any rust and unwanted paint from the roof surface, then blast some water over the roof to ensure every rust and dust is removed.

Rust converter

A rust converter is another great option for removing rust on your roof. Unlike other rust removers, rust converters work by
chemically reacting with rust, turning it into an inert black substance that can be painted over.

Before using it, you first have to clean the surface of the roof with a bristle brush.

This eliminates any excess rust from the roof and also prevents other contaminants from interfering with the reaction.

To apply it, use a roller or a brush.

Primer

applying primer to metal roof

Once you’ve cleaned and dried the surface of your rusty roof, applying a primer is your next step. The primer stops the rust from regenerating and spreading throughout your roof.

Oil-based metal primers have proven to be very effective for this task. 

You can find the best primers on Home Depot, Amazon, Lowe’s, or your local home improvement store.

Paint

Painting your roof should be the last step of this process. Once the primer is dry, apply the paint to your rusty roof and give it some time to dry. If you’re painting different paint coats, ensure that each coat first dries before applying a new one.

painted metal roof

What are the best rust converters?

There being tons of rust converters in the market, it can be hard to determine which one is good for you. Here are our picks of some of the best rust converters in the market.

Best overall

Corroseal Rust Converting Metal Primer

Being part of the Corroseal Brand, this is arguably the most efficient Rust converter in the market. It stands out in effectiveness, flexibility, durability, and cost.

Corroseal Rust Converting Metal Primer

Key Features

  • Water-based rust converter
  • Easy to brush, roll and spray
  • Non-flammable
  • Requires just one coat to get results
  • Great for large scale projects

Best budget

Evapo-Rust ER012

Evapo-Rust ER012 is one of the top-rated rust converters in the market. It works differently compared to other converters in the market by avoiding the acid-based formula. It’s, therefore, one of the safest yet efficient and cost-effective brands in the market.

Evapo Rust ER012

Key Features

  • Biodegradable, non-corrosive, and non-toxic rust converter
  • Water-based rust converter
  • Removes heavy rusting from the metals
  • Available in 1 gallon
  • Cheapest on our list

Best runner-up

Permatex 81849-12PK Rust Treatment

Permatex 81849-12PK Rust Treatment stands out from the crowd, using formic acid instead of the phosphoric acid formula used by most manufacturers. This makes it less hazardous than most rust converters, even when it comes in contact with eyes and skin.

Permatex 81849 12PK Rust Treatment

Key Features

  • Easy to apply – comes in a spray bottle
  • Very effective protective primer
  • Dries faster than most converters
  • Less acidic compared to other converters

What to look for in a rust converter

Before settling for a rust converter, here are some factors you should consider to determine if the converter suits you.

Application method: Rust converters can either be sprayed or brushed and rolled. Look for a converter that you’re comfortable applying.

Drying Time: The faster a rust converter dries, the better. Most converters take 24 hours, but some take longer.

Durability: You want a rust converter that gets rid of rusts for decades. So, look for converters with formulas that focus on durability.

Toxicity: Go for rust converters that are environmentally friendly with low toxins and one that’s gentle on the skin.

Cleaning: Applying rust converters can be messy. Look for a converter that’s easy to wash off and doesn’t stain your clothes or skin.

Do you spray or roll a metal roof?

It depends. Spray painting is fast, easy, and provides more uniform textures. It also appears more professional and consistent compared to roll painting. However, using spray cans can be wasteful, especially when there’s wind. It is only appropriate for homes with steep roofs.

On the other hand, using a roller and a paintbrush is more effective in covering all corners of your roof. It’s, however, more difficult and takes a lot more time.

What are the trendy colors for a metal roof in 2021?

Light colors; Tan, Shakewood, Hollow Grey, Mission Brown, Beige etc. Painting your roof drastically improves its appearance and appeal in the market. However, with roof paints lasting more than a decade, you just can’t choose any color. You need a roof paint that will still look great even when its color fades.

That’s why light colors are projected to keep trending even in 2021. Darker colors may look good in the first years, but they make your home look older when they fade.

Do I need 1 or 2 coats of paint?

Two paint coatings. When seeking to eradicate rust from your roof, using one paint coat will only provide a temporary solution. With two coatings, the first one is usually the primer that prevents rust growth and spreading, while the second coating refers to the paint of your choice.

Using 2 coats also gives your roof better durability against the harsh weather conditions it’s exposed to daily.

How long does paint on a metal roof last?

10 – 15 years. There are several factors that may affect the durability of your metal roof paint. The paint may last a bit longer or shorter depending on your maintenance practices, the weather conditions in your area, and the type of paints you go for.

However, thanks to modern technology today, you can be confident that the paint you choose will last for at least 10 years.

Keep in mind, your roof paint may fade a little after the first few years, but that shouldn’t trouble you. Its longevity will still be okay.

FAQ's

Yes! There’s no problem with painting over your rust converter; just be sure to first allow the converter to dry. This could take anywhere from 24 – 48 hours.

Timothy Munene
Author: Timothy Munene - Timothy is a freelance writer and an online entrepreneur.