SpecTopics: Polyiso Insulation Facers - GRF vs. CGF
Rigid polyisocyanurate (polyiso) insulation board is manufactured in a variety of types for use in wall, roof, and other building construction applications. The different types of polyiso insulation board are defined within the classification system contained in ASTM C1289 Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board. One of the primary attributes that may be used to differentiate the different classifications of polyiso is the type of facer or facing material used to manufacture each product.
Facers and facing materials serve a variety of functions in the production and use of polyiso insulation. Beginning with the manufacture of polyiso board, they are used to contain the foam core during the production process. After manufacture, they add strength and dimensional stability to the finished insulation board. Additionally, facers and facing materials may serve several functions during the working life of the product, beyond contributing to strength and dimensional stability. Depending on the type of facer or facing material, these functions may include providing a substrate compatible with other building materials, reducing water absorption and water vapor permeance, restricting air movement, increasing thermal resistance, creating a drainage plane to shed water, and adding radiative properties to wall and roof assemblies.
Two of the most popular facers for polyiso insulation are Glass Reinforced Facer (GRF) and Coated Glass Facer (CGF).
GRF is composed of a cellulosic fiber felt containing glass fibers. These felts are made with organic fibers, inorganic fibers, or mixtures of organic and inorganic fibers. This facer is compatible with all adhesives and self-adhered technologies.
CGF is composed of coated polymer bonded fibrous glass mats bonded with organic polymer binders and coated with organic polymer, clay, or other inorganic substances. The coating may be applied either to the glass fibers before bonding into mats or after the glass mats are bonded together. Glass fiber mats are used uncoated or coated. This facer offers enhanced performance through superior moisture resistance. CGF also offers increased resistance to foot traffic, hail, wind uplift, and fire.
Please note, because no current ASTM standards are available for GRF or CGF products, the definitions provided above rely on generic descriptions of facer and laminate materials currently available in the marketplace using terms common to these products. These facers are produced by a number of different manufacturers in North America, and the properties of the facers themselves may be altered when used to manufacture polyiso boards. In addition, the properties of polyiso boards such as water absorption, vapor permeance, strength, and dimensional stability may vary depending on the exact composition of a given type of facer. However, in all cases the final product shall always meet the requirements of ASTM C1289.
To learn more about polyiso products, refer to the Polyiso Product Reference Guide on the Carlisle website.
If you have any questions regarding Polyiso Insulation Facers, please contact Thomas Swope at thomas.swope@carlislesyntec.com.
Facers and facing materials serve a variety of functions in the production and use of polyiso insulation. Beginning with the manufacture of polyiso board, they are used to contain the foam core during the production process. After manufacture, they add strength and dimensional stability to the finished insulation board. Additionally, facers and facing materials may serve several functions during the working life of the product, beyond contributing to strength and dimensional stability. Depending on the type of facer or facing material, these functions may include providing a substrate compatible with other building materials, reducing water absorption and water vapor permeance, restricting air movement, increasing thermal resistance, creating a drainage plane to shed water, and adding radiative properties to wall and roof assemblies.
Two of the most popular facers for polyiso insulation are Glass Reinforced Facer (GRF) and Coated Glass Facer (CGF).
GRF is composed of a cellulosic fiber felt containing glass fibers. These felts are made with organic fibers, inorganic fibers, or mixtures of organic and inorganic fibers. This facer is compatible with all adhesives and self-adhered technologies.
CGF is composed of coated polymer bonded fibrous glass mats bonded with organic polymer binders and coated with organic polymer, clay, or other inorganic substances. The coating may be applied either to the glass fibers before bonding into mats or after the glass mats are bonded together. Glass fiber mats are used uncoated or coated. This facer offers enhanced performance through superior moisture resistance. CGF also offers increased resistance to foot traffic, hail, wind uplift, and fire.
Please note, because no current ASTM standards are available for GRF or CGF products, the definitions provided above rely on generic descriptions of facer and laminate materials currently available in the marketplace using terms common to these products. These facers are produced by a number of different manufacturers in North America, and the properties of the facers themselves may be altered when used to manufacture polyiso boards. In addition, the properties of polyiso boards such as water absorption, vapor permeance, strength, and dimensional stability may vary depending on the exact composition of a given type of facer. However, in all cases the final product shall always meet the requirements of ASTM C1289.
| ASTM C1289 Classification | Facer or Facing Material | Compressive Strength | |
| Type | Class | Both Sides | |
| II | 1 | GRF | Grade 1: 16 psi Grade 2: 20 psi Grade 3: 25 psi |
| II | 2 | CGF | |
| II | 4 | CGF | Grade 1: 80 psi Grade 2: 110 psi Grade 3: 140 psi |
To learn more about polyiso products, refer to the Polyiso Product Reference Guide on the Carlisle website.
If you have any questions regarding Polyiso Insulation Facers, please contact Thomas Swope at thomas.swope@carlislesyntec.com.
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