You’ve just built a new metal building. After plenty of time and effort, you’re pleased with the results, but your hard work is not over yet. Sure, you could stick some particularly durable equipment in there, but you have one last step; insulation. But what can you use to insulate it?

Spray foam is an effective insulator for any metal building, and you, or a professional installer, can apply it to any surface for an airtight, water-resistant seal. As long as you have the proper protective equipment, installing spray foam is safe and easy, so you can apply it wherever you would need to.

Spray foam may be an effective insulator for metal buildings, but where can you apply it? Should you spray it straight onto a metal surface or put something down first? What protective equipment should you use when applying spray foam, and how exactly do you install it?

Spray foam insulation may not be as challenging as you think. Read on to learn everything you need to know about spray foam, including installing it in metal buildings!

Can You Use Spray Foam Directly On Metal Buildings?

If you’re wondering whether you can safely apply spray foam directly onto the surfaces of your metal building, the answer is yes!

There is a common myth that spray foam insulation will corrode or oxidize metal or that lower-grade spray foams are acidic in composition. 

Ultimately, neither of these assumptions is correct in the modern era- any modern spray foam is safe for use on metal buildings.

As a non-corrosive, neutral agent, spray foam is perfectly safe to apply directly onto metal buildings as long as you take the necessary prior precautions.

When applying spray foam insulation directly on metal buildings, simply ensure that your workspace is well-ventilated, clean, and free of excess moisture.

Spray foam may be an excellent vapor barrier, but this lack of water transfer also means that any water caught between it and the metal may remain in place and corrode your building, especially if you are not using a premium product.

Additionally, closed-cell spray foam comes out at a higher temperature than your metal building will be in an average environment, which can cause condensation.

In these cases, you may need to wait for the condensation to disappear before applying another layer. If you or your installer uses a premium product that does not retain water, you should be safe.

Consider taking measures to ensure that your surface, spray foam, and air temperatures are all comparable, preferably around 70-80 degrees Fahrenheit.

However, this rule is not universal. Your spray kit may follow different requirements, so you must thoroughly read any directions that come with it.

Thankfully, once you have applied your spray foam insulation, you never have to worry about condensation again!

Should I Apply Spray Foam Insulation Directly To Metal Buildings?

Ultimately, whether you can do something and whether you should are different questions. If you’re asking whether you should apply spray foam insulation directly to metal buildings, the answer is yes, if that’s what you’d like to do!

Everybody has different needs and wants to get separate objectives out of their building. Therefore, it is challenging to claim which insulation may work best for you.

However, when you apply foam insulation directly to the surfaces of your metal building, you save space and build an energy-efficient, safe, sturdy environment that can suit many of the most common uses of a metal building.

Both varieties of spray foam grant significant structural benefits to your metal building. Open-cell spray foam is more flexible, so it can move as your building does; strong winds or settling foundations will not crack or damage your insulation. 

On the other hand, closed-cell insulation is more rigid in composition. While it will not stretch as well as open-cell spray foam, it can resist certain stresses and damages that would otherwise harm your metal building.


  • Effective insulator
  • Effective water barrier
  • Reduces rates of condensation once fully cured
  • Increases structural strength


  • Harder to remove if you face issues with your structure or insulation
  • Must have a well-ventilated workspace
  • Must keep an eye out for condensation

How to Properly Use Spray Foam With Metal Buildings

You want to jump straight into insulating your metal building, but unfortunately, there are certain measures you must take beforehand.

You must know where to apply your spray foam and what the best type of spray foam for insulating a metal building is. Additionally, you should learn the exact process required to safely apply your spray foam insulation. 

If you choose to hire a team of professional insulation installers to apply your spray foam, you don’t necessarily need to concern yourself with this information. However, it’s best to know what goes into your property, so you may want to read on anyway.

As a DIY installer, this information will be vital to you!

What Spray Foam Should I Use?

The two varieties of spray foam are not interchangeable, but at the same time, one is not inherently better for metal buildings than the other. 

Closed cell is a popular choice for metal buildings, but the real deciding factor is whether you plan on using a vapor barrier.

Closed-cell insulation acts as an efficient vapor barrier when fully cured, but open-cell insulation can take on more liquid due to its air-pocket composition.

Open-cell spray foam is an excellent option when applied in conjunction with a vapor barrier. However, some varieties of spray foam exist with a specific formulation to minimize or negate water retention.

Whether you are installing your spray foam yourself or having a professional install it for you, consider finding a spray foam variety that will not retain water.

A professional installer should be skilled enough to prevent condensation buildup during the application, but a premium product will keep your insulation more secure in the long run.

Where Should I Use Spray Foam?

Spray foam is a versatile insulator. Ultimately, you can apply spray foam to any surface that requires it; popular choices are walls and ceilings. 

You can apply spray foam to your floor joists, various corners, or even on the sides of electrical outlets to prevent drafts.

However, you should avoid using spray foam near any sources of high heat, such as boilers and canned lights.

Step 1. Tape Off Vital Locations

Before getting to your insulation process, you must tape off the places that you do not want to insulate. Using classic masking tape, cover up any locations where you want to remain foam-free.

Apply masking tape and painter’s plastic to surfaces such as windows, switches and outlets, and any miscellaneous items in your metal building- though you should prioritize taping up your floor. 

Ideally, you should remove as many items from your metal building as possible before applying spray foam insulation.

However, if you do not have the time or otherwise cannot move them, covering them in a layer of tape- or a layer of protective material, such as dropcloth or a plastic tarp secured by masking tap for larger objects- will provide plenty of protection from spray foam.

Step 2. Apply Your PPE

Next, you should apply personal protective equipment, also known as PPE. The pieces of equipment you should utilize for this project are as follows:

  • A respirator
  • A full-body covering
  • Gloves
  • Eyewear

Applying PPE is vital, as spray foam can exude noxious gasses while applying and curing.

Step 3. Set Up Your Foam Kit

Spray foam kits are readily available at any home improvement retailer, or even on Amazon. Unfortunately, there are no universal directions for these kits, and each one functions uniquely.

Thoroughly read the instructions that come with your foam kit so that you can easily set it up and use it with minimal effort or issue.

Step 4. Apply Your Spray Foam

During this step, you will apply your spray foam. Use long, even strokes to get an even coverage of your metal building, but do not spray your foam on too thick; remember that it expands rapidly.

Prioritize the edges of your columns and girts to form an airtight seal around your building’s joints. Afterward, use your long, even strokes to spray down the middle of your wall panels.

Use zip ties or other fasteners to hold items such as wiring in place, where spray foam will not push them out of the way or cause damage when expanding.

Step 5. Clean And Cure

Now comes the easy part- waiting. Spray foam takes 24 hours to cure, so in the meantime, feel free to begin cleaning up.

While wearing your PPE, you can remove your masking tape and clean up any extraneous foam to minimize later effort.

To maximize your efficiency, consider trimming any excess foam before vacuuming dropped foam bits.


Justin's been in construction for over 20 years in both new build and renovation. With experience in both commercial and residential construction, he specializes in healthier and more energy-efficient homes.

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