Most metal siding comes pre-finished in one of any array of colors, and it’s very durable with a finish that’s meant to last. Even so, it can chalk, fade, and eventually rust over time, so it’s important to maintain a healthy finish to prevent eventual corrosion.

Luckily, metal siding is one of the best exterior finishes to paint since it’s simple and doing it the right way lasts ages. It is important, though, to make sure you tackle the project the right way to prevent mistakes that could cause the paint to chip or crack and need to be repainted sooner than later. Making sure to go through the right processes and use the correct products will ensure a long-lasting coat of your favorite color paint, so keep reading for steps, tips, and tricks to the perfect coat of paint on your metal siding.

What is Metal Siding and Why Use It?

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When choosing exterior material for siding, many factors come into play. Some are more durable while others have a more natural aesthetic, and still others require little to no maintenance. Metal is one that’s known for lifetime durability and minimal maintenance, so it’s easy to see why it’s such a popular choice. Metal siding is usually composed of steel or aluminum, both of which have all the low-maintenance benefits of vinyl with greater durability and longer warranties. It’s a little pricier than vinyl, but is still much cheaper than wood siding, stucco, or brick, and the added durability makes metal siding more than worth the price.

When to Paint your Siding

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Nothing lasts forever, not even the best exterior finishes. Everything in your home will require maintenance eventually, and it’s crucial not to delay when it’s time to do so, otherwise the situation could worsen and you could incur costly damages that could have been avoided with regular maintenance. 

Your metal siding might last the entire time you’re living in your house, decades even, if you take care to wash it often enough and repair damages as soon as they occur. But over a significant period of time, or if (accidentally or on purpose) repairs are neglected, your siding could begin to fade, chalk, or rust and eventually require TLC and a coat of paint to protect the siding from further corrosion. 

Chalking, fading, and rusting are all good reasons to paint your home’s siding, so let’s look into each scenario to see when it’s time to call it and go ahead and put a fresh layer of paint.

  • Chalking: We all know what chalk is. It leaves a powdery finish on every surface it contacts and can be extremely helpful in some settings like playing pool or in the classroom, but it’s definitely not something you want to see on your siding. But when the elements come into contact with your metal siding, especially if you live in hot, damp climates, the surface can begin to develop a powdery residue caused by a chemical reaction between the metal and alternating sun and moisture exposure. 

A good cleaning could potentially rectify this, and cleaning the siding once to twice per year will usually prevent it happening in the first place. But if the chalking has gone untouched for too long the color underneath will fade and require paint to restore its luster.

  • Fading: Fading can occur because of unattended chalking of your metal siding, but even if you take perfect care to never allow chalking, fading can occur over time due to excess sun exposure. In this case, you’ll probably notice that the West side of the home is affected before the rest, with the whole home showing signs of fading over the next five to ten years. 

There are products available that can be applied to the siding each time you clean it to extend the life of the color and prevent fading, but if you’re already noticing a decrease in the intensity of the color of your siding the only way to move forward is to paint the home. Fading, however, is simply an aesthetic problem and isn’t necessary to resolve unless you simply don’t like the look- it won’t cause further problems for your siding.

  • Rusting: Rusted metal siding is the worst-case scenario, and it will always lead to further corrosion if left unchecked. Rust will literally spread and eat your siding leaving your sheathing exposed to the elements for mold, water damage, and pests to enter your home. It’s imperative that if you notice rust on the exterior of your home you remove it immediately.

If the rust is new, you can remove it with a metal brush and apply rust-inhibitive chemicals to the area to prevent its spread, and repaint for looks if you like. If the rust is further developed to the point of corrosion, however, you might need to replace part of your home’s siding and paint the rest of the house to match (since even if you purchase the same color siding you began with it’s unlikely to match because the rest of your home’s siding will have faded over time). 

How to Prep for Painting

Before painting, you’ll need to prepare the siding by cleaning it thoroughly and removing any and all rust from the surface. This will allow the paint to go on smoothly without bubbles, bumps, or blemishes. If you neglect to prep you’ll end up with chips and grooves that won’t just look bad but will allow rust to develop. 

How you clean is up to you, but as long as you remove all debris like chalk, dust, dirt, mildew, and rust, you’ll have a clean surface to begin painting. Here are a few helpful cleaning tips for different circumstances:

  • If mildew is present on the siding, soffit, or gutters, use a mildew solution or a mixture of water and bleach or vinegar to prevent the spread. Invisible mold spores can spread beneath the paint unless you use a solution designed to kill them. Let your solution rest on the surface for at least ten minutes to allow it to kill all mold or mildew.
  • Even if you don’t need to paint the underhang or gutters, it’s a good idea to clean those as well since dust and debris from those areas can fall onto the wet paint or work their way underneath the paint and ruin your paint job.
  • If you pressure wash and still see some discoloration from dirt or mud, try using a brush to remove tough stains before painting. You want as clean a surface as humanly possible.

Once your surface is completely clean, you can finish prepping the siding by sanding the entire surface until there are no slick/shiny areas. Paint won’t stick to slippery surfaces, so make sure they’re all dull. If you need to apply a rust-inhibitive coating, do this after you’ve sanded. Most rust inhibitors won’t prevent paint from sticking.

How to Paint the Metal Siding

When it comes to the actual painting, this might just be the easiest step. You’ve used enough elbow grease cleaning, and this step is mostly methodical painting rather than heavy-duty labor. If you have access to a sprayer, this is recommended as it provides even coverage and it’s easy to use on hard-to-reach places a brush or roller can’t quite get to, but you can also roll and brush on the paint. Here are the tools and products you’ll need:

  • Paint sprayer OR large rollers with long handles and brushes.
  • Painters’ tape.
  • Plastic window masking.
  • Sharp knife (to cut masking to size).
  • Primer for your type of metal siding.
  • Oil-based metal paint.
  • Exterior acrylic latex top coat.
  • Ladder.

Don’t cut corners with these tools and materials. Using the wrong paint or failing to cover your windows and trim could leave you in worse shape than before you even began your prep. If you follow this order and use the right materials, you’re less likely to make mistakes and experience peeling or chipping soon into the life of your paint job:

1- Protect your windows: Before spraying or rolling your home’s metal siding, make sure you use painters’ tape and plastic masking to cover any areas you don’t want painted like trim, windows, soffit, gutters, etc. You can use your sharp knife to cut masking to the perfect size for larger areas and place carefully ensuring every inch you don’t want painted is covered.

2- Prime the siding: When you’ve added a protective layer to all excluded areas, you can use your rollers or sprayer to paint your metal siding. Make sure you apply primer that’s specifically made for either aluminum or steel accordingly, as their composition is different and requires different chemicals for maximal adhesion. The right primer will stick to the metal and the paint over it both, which prevents chipping or peeling.

3- Apply your paint: After priming, you can add as many layers as necessary on top of the primer to achieve a solid color with no streaks. Allow the paint to dry fully between coats so you can accurately judge how many coats are needed. Also, make sure the paint is oil-based.

4- Apply a top coat: You theoretically could stop after painting, but if you want your paint to last and prove to be maximally weather resistant apply a latex top coat designed for exterior siding. This will provide long lasting color, prevent chipping and peeling, and keep rust from forming on the metal.

Once you’ve finished painting metal siding, you won’t have to again for a long period of time since metal siding is renowned for its durability. Just make sure to clean on a routine schedule to maintain your flawless paint job.

Editorial Contributors
Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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