Can You Spray Foam a Metal Building and Get a Complete Air Seal?

By: Eric Garcia on October 2nd, 2024

So, you’ve got a metal building, and you’re considering spray foam insulation.

Maybe it’s a pole barn, a shop, or even a storage facility. The big question on your mind is: Can you spray foam a metal structure and get a complete seal on the building envelope?

The simple answer is yes, yes, you absolutely can. But it’s important to understand how this process works and what to expect to make sure you’re getting the best possible results.

In this article, we’re going to break down the key points to know when using spray foam insulation in a metal building. We’ll cover everything from the different types of spray foam to look out for to those tricky spots that are easy to miss.

Let’s get started.

Why Spray Foam is the Best Insulation for Metal Buildings

Metal buildings are unique.

They’re built to be sturdy and last, but they come with their own set of challenges when it comes to insulation. Unlike traditional wood-framed structures, metal buildings have a lot of joints, seams, and hard-to-reach areas that can lead to significant air leakage if not properly sealed.

That’s where spray foam insulation steps in as a game-changer. It can expand and fill every crevice, creating an air-tight barrier that prevents outside air from getting in and keeps the conditioned air inside.

The result? A much more comfortable and energy-efficient space.

But it’s not as simple as just spraying and walking away. To ensure a proper air seal in a metal building, you and your contractor need to do a thorough inspection of those potential problem areas.

Hard-to-Reach Places in Metal Buildings

When considering spray foam in metal buildings, consider all those nooks and crannies where air can slip through.

Just imagine: You’re looking at the inside of your pole barn, and everything seems fine. But if you look closer at the junctions where the walls meet the roofline or the corners where the beams connect, you’ll see gaps that you might not have noticed before.

Here are a few common areas in metal buildings where air can escape.

I-Beams and Joists: In large structures, like barns or commercial buildings, you might have I-beams at the top of the walls where they connect to the roof. Behind these beams, hidden spaces can be easily missed unless you’re inspecting closely.

Roof-to-Wall Gaps: The seam where the roof meets the wall is notorious for small gaps that can’t be seen without standing right under or above them.

Electrical Panels and Openings: These are typical problem spots where air can leak through.
Interior-to-Exterior Wall Connections: If you have interior walls butting up against an exterior wall, there’s often a gap that isn’t visible from the inside.

These areas require special attention to ensure you get a complete seal with the spray foam insulation in your metal building.

How to Ensure a Complete Air Seal in a Metal Building with Spray Foam

So, how can you get all of these areas properly insulated? It comes down to planning and communication.

Before the project begins, do a detailed walkthrough with your contractor. Make sure to point out any areas that concern you. Take note of where different building materials connect and any areas where the exterior elements could come into contact with your interior spaces.

Here’s a checklist to keep in mind.

Inspect Beams and Joists: Check behind and around any visible beams. If necessary, create an access point for the spray foam if there isn’t one.

Evaluate Roof-to-Wall Connections: Make sure your contractor is paying attention to the roofline, as this is one of the easiest places to overlook.

Address Hidden Gaps Around Panels and Doors: These are common air leakage spots.
Review Before and After: Do a walkthrough before and after the project to ensure no areas are missed.

The more thorough you are during this process, the better results you’ll achieve.

Open Cell vs. Closed Cell Spray Foam: Which to Use?

When it comes to spray foam, you have two main options: open cell and closed cell.

Both can be used for spray foam insulation in a metal building but have distinct characteristics.

Open Cell Spray Foam

Open cell spray foam is known for its ability to expand more than closed cell, making it ideal for filling small crevices.

This is because open cell foam has a high expansion rate, meaning it can quickly expand into all those hidden nooks and crannies. It’s often used in areas where a complete fill is necessary, but it’s important to remember that it’s softer and has a lower R-Value per inch compared to closed cell foam.

Closed Cell Spray Foam

Closed cell spray foam, on the other hand, is denser and has a higher R-Value per inch, making it better for thermal insulation.

While it doesn’t expand as much as open cell, it still provides the same tight air seal and is more rigid.

Which One Should You Use?

It depends on your needs.

If you want a denser material that can be knocked into, then closed cell spray foam is your best option. But if you’re dealing with hard-to-reach spots and want to ensure every crevice is filled, open cell might be your best bet.

How to Spray Foam a Metal Building the Right Way

So, how do you spray foam a metal building correctly? It comes down to working with a knowledgeable contractor and understanding the unique requirements of your structure.

Here’s what you need to know.

Choose the Right Foam Type: Select between open or closed cell spray foam based on your building’s needs.

Seal All Gaps and Joints: Make sure to cover those hard-to-reach areas like I-beams, roof-to-wall connections, and panel openings.

Use Proper Thickness: Ensure your contractor is applying the foam at the recommended thickness to achieve the desired R-Value.

Do a Final Inspection: After the foam has been applied, do another walkthrough to confirm all problem areas were addressed.

Adding Spray Foam Insulation to a Metal Building

Metal building spray foam insulation is an effective solution for creating an air seal that boosts energy efficiency and comfort.

If you have any other questions about spray foam for metal buildings, check out our Learning Center. There, you will find a bunch of great resources to answer your foam insulation questions.

Understanding the Installation Process of Spray Foam Insulation for Commercial Buildings

The Best Spray Foam Insulation for Your Pole Barn: Open Cell, Closed Cell, or Both

Installing Spray Foam Insulation in Metal Buildings When It’s Cold

About Eric Garcia

Eric brings his knowledge and training in building science, training in spray and injection foams from the manufacturers, more than eight years installing foam insulation, as well as selling and managing in the foam insulation industry. He is also BPI and Dale Carnegie certified and has taken several building science courses, including air sealing and building envelope. Eric is the Professor of Foam on our educational YouTube series Foam University. Even when Eric is off he is usually still “working” or thinking about work, but when he can get away he enjoys camping, hiking, hunting, and woodworking.