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Should I Spray Foam My Metal Building?

October 16th, 2024 | 5 min read

By Kilian Agha

If you've got a metal building on your property, you're probably considering different insulations. After all, if you want to keep it cool in summer and warm in winter, you need some kind of insulation inside. Is spray foam the right choice for your metal building?

South Central Services has insulated hundreds of new and existing structures across southern Pennsylvania. We have sprayed many metal buildings and pole barns with closed cell spray foam. Spray foam is usually the best option for metal buildings, although there are alternative insulations you can choose from.

By the end of this article, you will know:

  • The benefits of spray foam in metal buildings
  • The drawbacks of spray foam in metal buildings
  • What insulations to choose when spray foam is out of budget

Pros Of Insulating Metal Buildings With Spray Foam

There are several benefits to insulating metal buildings with closed cell spray foam. Here's a preview.

  1. Condensation management
  2. Insulation longevity
  3. Insulation versatility
  4. Insulation performance
  5. Conditioning efficiency

Let’s examine each of these in more detail.

1. Spray Foam Helps To Manage Condensation.

Condensation is a serious concern for metal buildings. Metal is a natural conductor, which means metal buildings are highly conductive. If you're trying to prevent heat from infiltrating or escaping, metal won't help. It's simply a conduit for heat, no matter the time of year.

If the insulation in a metal building allows air to pass through, the dew point will cause condensation. As the air infiltrates, the temperature difference between the inside and outside of the building will cause the vapor content in the air to condense.

Installing closed cell spray foam on the roof of a metal pole building. The building is tall enough to require scaffolding to reach the roof.

Closed cell spray foam can create both an airtight seal and a vapor barrier at 2 inches of depth. With spray foam directly adhered to the metal, air and vapor cannot infiltrate.

This prevents condensation on the walls and other related problems, including mold, mildew, and wood rot.

2. Spray Foam Will Last For A Long Time.

Spray foam is meant to be a permanent insulation solution. Once spray-applied and adhered in place, spray foam shouldn't move. It won't be disturbed without effort. Spray foam also maintains its R-value over time.

Other insulations are much less permanent than spray foam. Even when installed correctly, batt and blown-in insulation performance deteriorates over time. Batt insulation will sag and can have gaps, while blown-in settles.

If you spray foam your metal building, you shouldn't have to worry about new insulation again.

3. Spray Foam Doesn’t Need Stud Layouts To Install.

Some insulation products, such as fiberglass batts, require a study layout to install. Without cavities to stuff the batts into, there is no way to make the insulation stay in the walls.

A team member at South Central Services scraping excess foam from a metal building for a clean finished look.

Since spray foam is spray-applied, it can conform to any accessible layout. Spray foam works for concrete, stone, wood, and metal. No matter the design of your metal building, spray foam can adhere to the walls to deliver seamless insulation.

4. Spray Foam Delivers Great Performance At A Shallow Thickness.

One of the greatest benefits of closed cell spray foam insulation is its high R-value. R-value varies by manufacturer, but as a general rule, closed cell foam has R-7 per inch.

Most insulations need more than 2 or 3 inches to reach the necessary R-value for a metal building. However, closed cell spray foam requires only 2 to 3 inches.

A pole building insulated with closed cell spray foam. The walls and the underside of the roof are covered with insulation.

5. Spray Foam Makes Heating & Cooling Much More Efficient.

Due to closed cell spray foam's high R-value, air-sealing, and vapor barrier capabilities, insulating with spray foam means more energy efficiency.

Poor insulation can make conditioning expensive if you want to heat and cool your metal building. Insulating with spray foam prevents air leakage and helps the building to better retain conditioned air.

Other insulations, such as fiberglass, allow air to pass through. Besides the condensation issues we've already addressed, air leakage with fiberglass also detrimentally impacts energy efficiency.

Cons Of Insulating Metal Buildings With Spray Foam

Despite all of the benefits of spray foam in a metal building, there are some drawbacks to using closed cell. If you're investing in insulation for your project, you want to be fully informed about the whole picture: the good and the bad.

We've identified three cons regarding installing closed cell spray foam in a metal building. These cons include:

  1. Cost
  2. Installation requirements
  3. Installation prep

Let’s examine each of these drawbacks in more detail.

1. Spray Foam Is An Expensive Investment Upfront.

Spray foam insulation is not an option for those on a tight budget. As a premium product, spray foam insulation is expensive. When you opt for spray foam insulation, you bear a significant cost to invest right at the beginning.

It is true that spray foam pays for itself over time through energy cost savings, but only some have the money to make that initial investment. If you have the flexibility in your budget to choose spray foam, you will recover that investment cost eventually. However, you may not be able to afford the upfront investment cost.

In these situations, there are other insulations for your pole building. No matter what you choose, condensation management should be a top priority, given the conductive nature of metal.

2. Spray Foam Should Not Be Installed As A DIY.

If you're researching spray foam for your metal building, you might be checking to see if it's a good idea before you commit to purchasing some DIY spray foam kits. Unfortunately, spray foam is not a DIY-friendly insulation.

If you want spray foam in your pole building, you need to hire a competent spray foam contractor. Spray foam is a cool insulating material with many benefits, but it is also complicated to install.

A pole building with garage doors being insulated with closed cell spray foam insulation.

Spray foam is created through a chemical reaction, and several variables in that reaction must be maintained for a good outcome. Ratio, temperature, and pressure are a few examples. DIY spray foam kits cannot monitor or control these variables.

Professional contractors spend hundreds of thousands of dollars on spray foam rigs filled with professional equipment. If you want the insulation in your metal building to be done right, you have to work with a professional. A competent contractor has the equipment and training to deliver all the "pros" we already discussed.

3. Spray Foam Does Require Some Prep Work In Certain Buildings.

Spray foam is an amazing insulation product, but it does require accessibility to spray. This is why spray foam cannot be used in existing walls with intact drywall.

Some metal buildings are already used as a woodshop, garage, or workspace. Depending on how the space is being used, the building walls may not be accessible.

If you want spray foam installed, some accessibility must be created. This could include moving things to the center of the building or moving items outside of the building itself. The metal structure doesn't need to be empty, but a professional contractor must be able to access the walls to spray.

As a general rule, there should be a minimum of 5 feet of space between the walls and any belongings inside the building.

Spray Foam Is A Great Insulation Choice When You Can Afford It.

Spray foam is the best insulation choice for your metal building if you can afford it. Given the unique properties of metal and the prevalence of dew point in our climate zone, spray foam insulation delivers excellent permanent performance.

A pole building insulated with closed cell spray foam on the walls and roof.

When budget is not a concern, spray foam is the best option for metal buildings in our climate zone.

When Spray Foam Is Out Of Budget, You Have Other Options.

Spray foam is not within everyone's budget. We are the first to say that spray foam is a premium product with a matching price tag. If spray foam is not an investment you can make right now, there are other insulations you can choose from.

A few options include dense pack, fiberglass blankets, and blown-in cellulose. No matter which insulation you choose, keeping these two things in mind is essential.

  1. Make sure your insulation is installed correctly to maximize its longevity and performance.
  2. Consider your climate zone and discuss your condensation concerns with a professional.

The Bottom Line About Spray Foam Insulation In Metal Buildings

Spray foam is one of the best options for metal buildings, especially in Climate Zone 5. Our team installs closed cell spray foam in the underslab, walls, and ceilings of metal buildings. Spray foam is seamless spray-applied and offers a high R-value, vapor barrier, and an airtight seal.

The upfront investment cost is the biggest drawback to installing spray foam in your metal building. If you cannot afford spray foam insulation, other insulation options are available. Whichever insulation you choose, be conscious of moisture mitigation. Metal buildings conduct heat, which makes insulation key to energy-efficient conditioning.

Now that you understand how spray foam performs in metal buildings, your next step is to:

Kilian Agha

Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends.