There are many options when choosing an insulation system for your next project.

Bill Beals

District Manager,

October 2, 2020


by Star Building Systems

Trends in Insulating Metal Buildings

In my last blog post, I shared my top 3 tips for insulating metal buildings, which included knowing code requirements that impact your projects, understanding the insulation options available, and ordering the metal building with the insulation system in mind. I received many questions about insulation systems; everything from when to opt for a banded liner system versus a long tab banded system, which continuous insulation systems satisfy code requirements, and what type of systems are best for specific applications. So, let’s take a deeper look at the latest trends in insulating metal buildings and the differences between each insulation system available in today’s market.

Metal Building Insulation Categories
Before we dive into specific insulation systems, it’s important to understand the basic categories that each system is classified under. The primary categories referenced throughout energy code literature include:

  1. Fiberglass systems, which consist of one, two or three layers of faced or unfaced fiberglass (or a combination) in either the roof or walls.
  2. Continuous insulation systems most often consist of a rigid polyisocyanurate or polyethelene foam core and can be used in roofs and walls.
  3. Insulated metal panels are a lightweight composite exterior wall and roof panels with metal skins and an insulating foam core.

Types of Fiberglass Systems
The fiberglass insulation systems most often used to meet code include Banded Liner Systems and Long Tab Banded Systems. Both systems provide High-R insulation to meet the latest codes, and both include two layers of fiberglass and banding. However, there are several key differences between the two, including:

  1. Aesthetics: In a Banded Liner System application, the purlins are covered by a fabric vapor retarder. In a Long Tab Banded application, the purlins are exposed. Pictured:
    Pictured: Purlins are covered in a Banded Liner System application

    Pictured: Purlins are exposed in a Long Tab Banded application
  2. What’s laminated: Both systems include two layers of fiberglass; however, in a Banded Liner System, neither layer is laminated. Instead, the white or black fabric included in the system serves as the low permeance vapor retarder. In a Long Tab Banded System (modeled above), the bottom layer of fiberglass (which faces the interior of the building) is laminated. The top layer is unfaced.
    Pictured: A typical Banded Liner System application

    Pictured: A typical Long Tab Banded application.
  3. Application: Unlike Long Tab Banded Systems, Banded Liner Systems are designed for use in both roofs and walls. Long Tab Banded Systems are roof only.
  4. Fall protection: Many Banded Liner Systems offer fall protection, such as Therm-All’s ProLiner™ Bi-Directional Banded Liner System, which provides tested leading-edge OSHA-compliant fall protection system. Long Tab Banded Systems typically do not offer fall protection.
  5. Code Classification and achievable U-values: Banded Liner Systems meet ASHRAE’s and IECC’S definition of a Liner System (Ls). Long Tab Banded Systems meet the definition of a Filled Cavity (FC) System in the latest ASHRAE 90.1 Standard. Additionally, Banded Liner Systems typically achieve better U-values than Long Tab Banded Systems.

Types of Continuous Insulation Systems
Continuous insulation systems (CI) have become more prevalent in metal buildings over the last few years, primarily due to two key characteristics: CI provides a high R-value per inch, and most systems are easy to install. Systems typically consist of a rigid polyisocyanurate or polyethelene foam core and the majority can be used in both the roof and walls. There are various continuous insulation systems available to meet code, and building manufacturers have components for this application. Contractors also must understand board insulation applications do require specific fire testing to be used in exposed applications. Many off-the-shelf board insulations do not meet the requirement. Additionally, insulated metal panels have gained market share in recent years, with a specific focus on wall applications.

Pictured: R-Seal® Continuous Insulation System

Insulated Metal Panels
Insulated metal panels (IMPs) are made up of factory-controlled foam insulation sandwiched between a finished metal exterior and an interior face. IMPs deliver a high R-value per inch and can be used to meet energy codes. A specific focus on IMPs for wall applications has emerged over the last several years.

Closing Remarks
As you can see, there are many options when choosing an insulation system for your next project. Often it boils down to budget, building requirements and contractor preference.

Bill Beals, District Manager of Therm-All, is a 32-year veteran of the metal building industry and a contributing member of several committees, including the Metal Building Manufacturers Association (MBMA) Energy Committee and NIA’s Metal Building Insulation Laminators Committee (chairperson). Bill also belongs to the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) and International Code Council (ICC), and is often invited to share his extensive energy code knowledge through presentations at industry conferences. Bill has contributed to many articles and reference guides, and authors a bi-monthly commercial energy codes blog called “The Code Man”. Beals can be reached at

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