Red Iron Building Insulation: Spray Foam or Fiberglass?

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Trying to figure out the best insulation for your red iron metal building? We got you covered!

In this post, we’re breaking down the two insulation options we offer: Spray Foam and Fiberglass. We’ll cover their pros and cons, talk performance (R-value), and lay out what you really need to know to make the right call for your building.

Why Insulating Your Texas Metal Building is a MUST?

Before we dive in, let’s cover why insulation is such a critical part of your build especially here in Texas, where the temperatures can be extreme.

Insulation does more than just keep things comfortable. It protects your investment, boosts energy efficiency, and helps your building last longer.

Top Reasons to Insulate Your Metal Building in Texas:

  • Thermal Control: Helps in regulating the temperature especially if you’ll be spending time inside.
  • Condensation Control: Helps control moisture can lead to rust or mildew.
  • Energy Efficiency: Insulation can help HVAC systems run more efficiently and effectively saving you money.
  • Building Longevity & Protection: Helps prevent long-term issues like rust and material degradation caused by water or moisture, hence, enhancing rigidity of the building.

What’s the R-value and Why Does it Matter?

R-value is a measure of how well a material resists heat flow. The higher the R-value, the better it is at resisting heat transfer.

Choosing the right R-value for your metal buildings is key, most especially under the Texas weather. It not only improves indoor comfort but also boosts energy efficiency, helping you save on heating and cooling costs year-round.

Spray Foam Insulation

Spray foam is a polyurethane material that’s sprayed on as a liquid and hardens into a solid, forming an airtight and moisture-resistant layer on the metal panels.

At WolfSteel, we only use closed-cell spray foam for optimal performance.

30x40 Custom Metal Building with Steel Balcony, Mezzanine and a Wraparound Porch.
30x40 Custom Red Iron Metal Building with Spray Foam Insulation

Closed-Cell Spray Foam R- Value

  • 1” = R-7
  • 2” = R-14
  • 3” = R-21 (maximum we install on 26G panels)

PROS

All-in-one insulation

Longer lifespan

Consistent R-value

Flexible installation timing

Reinforces walls & framing

CONS

Less visually appealing

Higher cost

Difficult panel replacement and leak detection

Extensive prep work

The natural color of spray foam is yellow, which is the standard option. But at WolfSteel, we also offer upgraded colors white, grey, and black for a more custom finish.

40×50 Weld Up Metal Garage in Soft Grey and Black Painted Spray Foam

Check out our blog about painted spray foam here. 

Fiberglass Insulation

Fiberglass also known as the Batt insulation is a lightweight, non-combustible glass fiber blanket on one side it has a reflective barrier and the other has a white plastic backing.

40x60 Red Iron Metal Workshop with Fiberglass Insulation

Fiberglass R- Value

  • 3” (Single Layer) = R-10

We only offer 3” fiberglass as a single layer on your red iron metal building. We can also offer double layer batt insulation for additional R-value.

  • Double layered can give up to R-19

PROS

All-in-one insulation

Enhanced aesthetics

Easy panel replacement

Quick installation

Sound dampening

CONS

Must be installed during construction

Shorter lifespan

Plastic backing

R-value depends on installation quality

50×80 Pre-Engineered Commercial Metal Workshop
50x80 Bolt Up Commercial Metal Building with Fiberglass in White and Black Backing Combo

Spray Foam vs. Fiberglass

Let’s break down the differences based on real feedback from our clients and their experiences.

Feature
Spray Foam
Fiberglass
R-value
1”= R-7 and 2”= R-14
3” (Single Layer) = R-10
Comfort & Temperature Control
Keeps interiors cool and steady even in Texas heat.
Provides insulation, but with a weaker thermal break than spray foam.
Condensation Control
Acts as a thermal break to prevent condensation.
Provides moisture barrier but depends on installation quality.
Durability
Long-lasting and holds up well over time.
Shorter lifespan; fibers can degrade and sag over time.
Installation
Can be installed after building construction
Fully installed once building is completed
Aesthetics
Standard color is yellow but now available in white, gray and black.
Clean white or black backing; preferred for polished, finished look in commercial projects.
Cost
Higher upfront cost (especially closed-cell), but performance depends on skilled installation.
Cheaper material, but labor-intensive install—overall cost ends up similar to spray foam.

What does WolfSteel think?

It all comes down to one question: What will your building be used for?

  • If you want the highest R-value, built-in vapor protection, structural reinforcement, and consistent climate control, closed-cell spray foam is the way to go. Yes, it comes with a higher upfront cost, but it can save you money over time in energy bills and maintenance.
  • If you prefer a clean, moisture-resistant insulation with sound dampening and easier panel replacement, fiberglass is an excellent choice. It offers strong R-values, a finished look that many clients prefer, and is installed during the building process with no need for extra work afterward.

If you are looking to meet a specific code or R-value, consult with us!

Insulating your building is just the first step don’t forget about insulated accessories. Including these ensures your insulation performs at its best and helps maintain energy efficiency throughout the entire structure. 

Learn more about insulated accessories here.

Choosing the right insulation isn’t just a small detail it’s a key decision that affects the comfort, efficiency, and longevity of your entire metal building. From battling Texas heat to protecting your structure from moisture and rust, the right insulation makes all the difference.

Check out our full video where we compare spray foam and fiberglass insulation.

At WolfSteel, we offer a variety of insulation options tailored to meet your building’s specific needs.

👉 Explore your options here and find the perfect fit for your Texas metal building.

📩 Email us at quotes@wolfsteelbuildings.com or give us a call at 844-941-0999 our team is ready to help you choose the best insulation solution.

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