Roofing

How To Purposefully Rust A Galvanized Roof? (4 Ways to Rust Metal)

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If you love the look of rustic steel, you are not alone. You might have wondered how to rust a galvanized roof at some stage purposefully. What good is a “new” roof if the environment it lives in is more Shabby-Chic? Luckily, I have some easy-to-follow methods to create the rust look for your roof, and it won’t lead to bankruptcy.

When you want to rust a galvanized roof purposefully, there are many household items that you can use to get the job done, like vinegar, salt, and even toilet cleaner. Throw hydrochloric acid and hydrogen peroxide into the mix, and you have the right oxidation-inducing ingredients needed for rust. 

When you have the right ingredients that promote oxidation, a little time on your hands, and the simple yet effective ways that I am about to share with you, then rusting a galvanized roof should be easy and fun to do. This article will share the methods you can use and offer alternative options if you are not a DIY person by nature.

What Is A Galvanized Roof

Steel, copper, aluminum, and tin are usually used in sheets for roofing. Steel metal sheets are the most affordable of the lot, and they have an expected lifespan of up to 30 years and more. Ungalvanized steel metal sheets will rust as they contain iron. When oxygen and water come into contact with iron, it forms a combination called iron oxide which will cause your metal steel roof to start rusting.

Manufacturers have implemented the act of adding a zinc coat to the steel sheets (galvanizing) to help prevent the sheets from rusting. The zinc coat acts as a shield and protects the steel from moisture and oxygen, two elements needed for the rusting process to start and protect the steel or iron sheet from corrosion.

The most common method used in galvanizing is hot-dip galvanizing. It’s the process of dipping the metal sheets in a bath of molten hot zinc.

Why Do People Rust Their Galvanized Roofs?

People are creative creatures by nature. One of the reasons to purposefully rust a galvanized metal roof is to create a rustic/country-style look that’s fitting to represent country life. Other reasons are that people like the vintage look-an element of something that battled through time- but remains and functions.

Others are forced to do it when their home’s design is in the rustic/vintage fashion for the roof to “fit” in with its surroundings. Whatever the reason, people purposely rust their galvanized metal roofs, gates, and ornaments, either before installing them or when it’s already a functioning piece of their home.  

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4 Easy Ways To Rust A Galvanized Roof

The common denominator when rusting a galvanized roof, using any of the ways listed below, is to remove the protective zinc layer on the metal sheets. Exposing the metal underneath will allow you to activate the rusting process when mixing water, chemicals, and oxygen before applying it to your sheets.

I will give you a moment to put your science hat on and then guide you in how to make metal rust with easy to find rust-activators in your home or chemical store:

1. How To Rust A Galvanized Roof Using Vinegar

Vinegar can be found in most kitchens, as it is a widely used ingredient in cooking, and you should have a bottle in your pantry. You may be wondering if simple vinegar will rust your shiny zinc-protected galvanized metal sheets?

Indeed, vinegar contains elements that will rust your roof sheets fast:

  • Acetic Acid
  • Water

What You Will Need:

  • Steel Wool
  • Sandpaper
  • Any Abrasive
  • Spray Bottle
  • Paper Towels
  • Acrylic Sealer

The first task at hand is to take the steel wool, sandpaper, or any abrasive and start scrubbing and sanding, removing the protective zinc layer as your primary objective. Spray vinegar over the entire metal sheet. The vinegar will immediately start the oxidation process when applied.

If you do not find a spray bottle, you can dip paper towels in vinegar and manually cover the metal sheets with the vinegar application. To ensure the best rust results, you may have to repeat this process a couple of times, as the vinegar will dry relatively quickly.

If you’re not entirely satisfied with your science experiment, then repeat the whole process, from the abrasive part to the vinegar application. Leave the sheets for 24-hours to see the effect of your handiwork.  Continue to apply vinegar until you are happy with the result.

 It is recommended that you apply an acrylic sealer to protect your handy work from corrosion that will impact the roof’s primary function: to keep the elements out of your home or structure.

Spray the acrylic sealer on each sheet and make sure to cover every single one entirely, as this layer will preserve the rust. Allow it to dry, usually 4-12 hours, and affix the “new” sheets to your home or outdoor structure.

2. How To Rust A Galvanized Roof Using Toilet Cleaner

Another item that should be in your cleaning cabinet already is the good old toilet cleaner. Unsure why toilet cleaner will work in making a steel sheet rust? It is because most toilet cleaner products, even the one’s without the harmful chemicals, contain:

  • Lactic Acid
  • Citric Acid
  • Water

What You Will Need:

  • Steel Wool
  • Sand Paper
  • Any Abrasive
  • Protective Gloves
  • Old Towel
  • Wet Cloth
  • Acrylic Sealer

Again, the most crucial action to be undertaken is to rid your metal sheets of the protective zinc layer. Gear yourself with protective gloves and use steel wool, sandpaper, or other abrasives to achieve this objective. Make sure to scrub/sand all of the sheets in their entirety.

Take the toilet cleaner and start applying it to the sheets (rub it in) with the old towel. The more toilet cleaner that you use, the better the result. If you want to add some dark spots on the metal sheets, here is what you need to do:

  • Pour some toilet cleaner on a section of the steel wool.
  • Place the wet steel wool on the metal sheet at random areas and let it dry.
  • Leave for 24-hours- less if it’s a sunny day.

Leave the toilet cleaner on the sheet overnight, as well as the wet steel wool. Take a damp cloth to remove the toilet cleaner and steel wool from the sheets. The rust effect should now be prominent on your sheets, and the added dark spots created by the steel wool should give you a very realistic rustic look.

Apply the acrylic sealer if you are happy with the general look of the sheets, as this will give the sheets a new protective layer to protect against corrosion and water. Spray each sheet with the sealer and dry (4-12 hours) before installing it onto the roof.

3. How To Rust A Galvanized Roof With Hydrochloric Acid And Hydrogen Peroxide

Hydrochloric acid, together with hydrogen peroxide, works great as a team when rusting new galvanized sheets. These products are available in many shops that stock chemical products and should be easy to find.

Because hydrochloric acid is such a powerful cleaning agent, which emits strong fumes that can damage the lungs and can also burn the skin when in contact, please follow safety precautions and wear the following:

  • Protective Mask
  • Safety Goggles
  • Protective Gloves
  • Protective Thick Clothing

What you will need:

  • Steel Wool
  • Sand Paper
  • Any Abrasive
  • Two Spray Bottles
  • Acrylic Sealer

Use abrasive agents, steel wool/sandpaper, or anything that will remove the protective zinc layer from the galvanized sheets. If you are happy that the metal will now be exposed to the chemicals about to be applied, put your protective gear on, and get ready to work very carefully.

Fill the two spray bottles with the hydrochloric acid in one and the hydrogen peroxide in the other. Avoid inhaling the harmful fumes from hydrochloric acid. If you are using a workbench inside a building, ensure it is adequately ventilated by opening up doors and windows.

Spray each panel with the bottle containing the hydrochloric acid first, followed by a coat of hydrogen peroxide. When the application has completely dried out, spray another layer of both chemicals to complete round two. Doing this on a sunny day will speed up the result.

After 24-hours, you should find that your once new galvanized roof sheets are now old-looking and rusty. If you are entirely satisfied with the result, you can spray each sheet with an acrylic sealer. Allow the acrylic sealer to dry, 8-12 hours, and install your new “old” roof.

4. How To Rust A Galvanized Roof With Hydrogen Peroxide, Vinegar, And Salt

Choosing to use this method when rusting your galvanized steel sheets will give you almost instant results. The combination of hydrogen peroxide, vinegar, and salt works exceptionally well together when used to turn metals into rust, as they are a mixture of chemicals that are the following:

  • Acetic Acid
  • Aggressive Oxidizer
  • Aggressive Corroder

What you will need:

  • Vinegar
  • Salt
  • Hydrogen Peroxide
  • Spray Bottle
  • Funnel
  • Bucket

Take a bucket and proceed to mix:

  • 16oz of hydrogen peroxide.
  • 2oz of vinegar
  • ½ tablespoon of salt

Proceed to pour the mix into the spray bottle using the funnel. Spray the sheets from to bottom, and you should see results immediately! Doing the work outside in the sun speeds up the oxidation process.

If you are not satisfied with the rust effect after the first several applications, then work yourself up to about seven coats. Make sure to seal your newly rusted metal sheets with an acrylic sealer before fixing them to the roof, or the sheets will rust even more. The choice is yours.

Will The Galvanized Metal Sheets Still Rust Naturally After Purposefully Rusting Them?

It will continue to deteriorate naturally after you have followed any of the above-listed ways regarding purposefully rusting your metal roof sheets. The rusting process will happen at a slower pace due to the acrylic sealer that you have applied.

If you choose not to apply the acrylic sealer, the metal sheets, which are now without the protective zinc layer, will continue to rust “normally” and at a faster pace.

Should you decide that your sheets have rusted enough and display the desired effect, you can add a protective layer to the sheets to slow down the process.

Where Can I Buy Rusted Galvanized Metal Sheets?

Not everyone is a DIY person by heart, and reading the above could seem too much effort for some, ultimately putting them off the rustic rust look altogether! However, fear not if you resonate with this category. There are businesses out there that sell galvanized metal sheets that already have the rustic rust look!

When ordering from a company that sells rusty roof sheets, ask whether there is a sealant on the sheets. If not, you can always add a coat of acrylic sealer to your “new” sheets before using them as roofing.

When researching for businesses that offer this particular service, you can usually buy “rusty” gutters as well to blend in with your new roof. Be sure to spread your search to scrap yards as well, and you might find the exact type of sheet that you are looking for rust and all typically at an excellent price!

Conclusion

If you are into a more rustic and vintage look for your home, including the galvanized metal roof sheets, then the easy-to-follow ways listed in the article should help you create that rust effect that you had in mind.

Don’t be afraid to experiment and re-apply the process if the sheets are not 100% to your liking. Practice makes perfect in this case, and it’s not hard work at all. Please feel free to try all the different ways to purposely rust your metal roof sheets, should one particular method not produce the appearance you had in mind.

For the quickest result, try the hydrogen peroxide, vinegar, and salt method. If you’re not too keen on DIY research who sells pre-rust galvanized metal roof sheets in your area, it should be easy to find these types of sellers.

Sources

How To Rust Galvanized Metal Roofing?

Rusty Metal Roofing and Antique Metal Sidings – Recla Metals

How to Rust Corrugated Metal | Hunker

Author

Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.