How to Paint a Metal Building

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There are many reasons that might prompt you to paint a metal building. For instance, you may want to change the color, or the painting needs refreshing, or there is damage on the building, and you need to paint it after a repair, odds are, you have most probably not painted one before.

So in truth, you need all the help you can get on how to paint a metal building, and that’s exactly what this article is all about. By the time you’re done reading it and watching the short video below, you’ll no longer have a problem painting your metal building.

A word of caution: The day you must pick to paint it must be a day when it is not expected to rain. It is best to have a cloud slightly covering the sky or early in the morning.

So let us get down to the process involved.

Things You’ll Need for Metal Building Painting

Before you start with your metal building painting job, there are a few tools you’ll need to make the job an easy one, and we’ve listed them below:

  • Water
  • Bleach
  • Paint
  • Wire brush
  • Ladder or scaffolding
  • A good paint sprayer like the ones here

With that out of the way, let’s now get to the step by step guide:

How to Paint a Metal Building

how to paint a metal building step by step
A commercial painter on an industrial lift spray painting a steel exterior wall or duct.

Here’s a step-by-step guide to painting a metal building:

1. Get the surface prepared

Although there are several methods on how to paint a metal building, It is only appropriate that before you apply paint on any surface, you should make sure the surface is clean free from any unwanted particles such as dust, debris, or chalk.

Now, this is where the bleach comes into play. Dilute the bleach with water if necessary and apply it to remove mold or mildew, if present.

With the help of the wire brush, you should remove any loose paint (in a case where you are changing the color) by scrubbing the particular area. If there is rust on the surface, you should also scrap it off. You can now finish it off by washing the area you want to paint by using warm soapy water.

You can use a cloth to wipe across the surface of the building to see if there are still any particles left. If there is, continue washing until they are no longer present.

You might need to use a pressure washer if the building is enormous. Be sure that the detergent or the soap you used in washing has been thoroughly rinsed off, and that the surface is allowed to dry properly.

The drying should not take more than two days. Make sure you take caution when using the ladder, scaffolding, or whatever means you used to get to the upper level of the building.

2. Protect the Doors and Windows

Just like painting any other thing, there are some parts of the building that is not intended to be painted, and as such, you need to protect those areas before you start spraying or using rollers to paint.

You can tape plastic sheets to protect those areas from being painted during the process.

3. Applying Primer

The primer is a preparatory coating material that allows better adhesion for the paint to a surface. Additionally, it also serves as protection for the material being painted; in this case, a metal. So doing this is in your best interest.

Since the structure of a metal building is somewhat more extensive and spreads across a large area in different directions, it is more efficient to use a sprayer or a roller rather than a brush for the painting no matter how big.

The use of primer is recommended in a case where the building is being painted for the first time or where the old painting has formed too much chalk.

Make sure you are using as a solvent-thinned primer that is best suited for a metal surface. You can then apply the primer using your desired method, two coats of primer are just enough to do the job.

4. Painting the building

Finally, what is left for you to do is to paint the building, what you’ve been looking forward to all along? Like it was mentioned earlier, it is recommended to use a paint sprayer or a roller (since it is for larger surfaces).

Remember, if you had used two coat of the primer; make sure the second coat is completely dry. Then clean up the primer in the paint sprayer and fill it up with the paint.

Unless the previous paint used was oil-based (in a case repainting), it is highly recommended that you use an appropriate acrylic-latex paint for metal buildings because it helps the metal against harsh weather.

The only reason why you must use an oil-based paint and primer is if the paint that was on the metal building previously was oil-based too.

Now as a form of precaution:

  • Do not walk on the roof if wet
  • Before stepping on any panel, be sure there is support beneath it
  • Do not walk in the gutters or on the flashing
  • Watch out when walking on the edges; do not walk too fast

Below is also a short video that’ll show you everything you need to know about metal building painting:

And that’s it! You’ve just learned how to paint a metal building; it doesn’t get easier than that. Next time you wish to do it yourself, just follow the steps we have listed in this post, and everything will be okay.

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