Globeclad Fire Resistant Facades

Glass Reinforced Gypsum (GRG)

“GRG” (Glass Reinforced Gypsum) is a molded product with a high strength to weight ratio that is used in construction to replace the disappearing art of plaster. In the past, “Master Plasterers” would reproduce stunning run-in-place architectural columns, domes, vaults, arches, cornices, etc… Today, there are very few “Masters” left. “GRG” produces these results in a premolded, light weight, time tested composite for far less the cost. It has been used on probably millions of projects all over the world to continue the “charm” of both traditional or classical architecture and to create the free flowing forms of modern design.
“GRG” is a multi-layered composite using only two basic raw materials: continuous strand fiberglass mats in a matrix of high density “alpha” gypsum cement plaster. A gypsum surface coat is applied to a mold (the “negative” of the shape required) and further alternating layers of fiberglass and gypsum are hand laminated until the desired thickness is achieved, typically a nominal 1/4”. The hand “lay-up” method allows consistent control of the shell thickness as well as the incorporation of embedded items for stiffness, strength, attachment and/or hanging. Once the “GRG” has set, the part will maintain it’s shape and it is removed from the mold, stored to prevent distortion, finished and inspected, and is ready to ship. Daily production is a function of environmental factors, piece size and profile and the cure rate of the gypsum; usually allowing a minimum of four to a maximum of six pieces per day from the mold. Large projects may require that multiple molds be made of the same shape to increase daily yield.

Multiple layers of continuous strand fiberglass mat cast into a matrix of high density gypsum cement plaster. Materials are polymer free. Shell thickness is a function of the number of fiberglass layers and the type of fiberglass used. Thicker laminates as req’d.

Plywood and/or metal at attachment/hanging flanges for fastener support.
Foam and/or wood “ribs” back-laminated into “field” areas of large profile/flat shaped parts for additional rigidity/flatness.

PHYSICAL CHARACTERISTICS: (minimum as per ASTM C1355 / C1381)

Shell Thickness

1/4” Nominal Standard (+/-1/8” / Unit) [6mm (+/-3mm] {1/2” min. at edges}

Glass Fiber

6% min. (by Weight) (Volumetric measurements not valid)


1.5 – 2.0 (lbs/ft2) [7 – 10 (kg/m2)] (varies with embedment/reinforcement)


Modulus of Rupture (MOR) 3200 ~ 3500 (PSI) [22 – 24 (Mpa)]
Flexural Modulus of Elasticity 1.3 ~ 1.9 x 106 (PSI) [1.3 – .9 x 107 (kPa)]

Ultimate Tensile (UTS)

1800 ~ 2000 (PSI) [12 – 14 (Mpa)]

Modulus of Elasticity

2.7 – 3.8 x 106 (PSI) [1.9 – 2.6 x 107 (kPa)]

Comprehensive Strength

7200 – 8300 (PSI)

Thermal Conductivity

4.0 – 4.2 (BTU/in/hr/ft2 /0F) [22.7 – 23.8 (W/m2 0C)]

Thermal Expansion Coefficient

8 x 10-6 (in/in/0F) [14 x 10-6 (mm/mm/0C]


ASTM E84-80 (Incombustible Building Material) Flame, Fuel = 0, Smoke = 0


(NBS Certification MEA 42-82) = 0


(Dry) 105 – 114 (PCF) [1680 – 1826 (kg/m3)]


95 RH (min.) (Rockwell Scale)




Dimensional – all directions +/- 1/8”


Warpage or Bowing +/- 1/16” /foot


Square / Skew /Diagonal +/- 1/8” in 10’


Out of Round +/- 1/16” / foot of diameter


Humidified Deflection: 1/8” max (Industry standard)

  • GRG is lightweight and strong: Reinforced with extremely resilient glass fibers, Glass Fiber Reinforced Gypsum is a building material that is quite strong. GRG is also light, weighing in at just two to three pounds per square foot. This is a great combination, allowing for the installation of sturdy elements without extra support.
  • GRG is malleable and versatile: Unlike other common building materials, fiber reinforced gypsum elements are crafted by casting them in molds. This allows for the creation of almost any size, shape, or texture. GRG is also versatile in terms of available finishes. GRG elements can be painted with flat latex, or they can be crafted to have a wood grain texture or look like copper, aged bronze, or sandstone.
  • Glass  Reinforced Gypsum is fire resistant: Gypsum, one of the main ingredients in GRG, is a mineral that will not burn. In addition to being fire-resistant, GRG elements are also capable of protecting areas behind them for approximately two hours.
  • GRG is made of non-toxic materials: Finding green building materials is important for many home and business owners, and GRG is an environmentally-sustainable choice. Glass Reinforced Gypsum is made from natural materials that are not considered pollutants. In addition, GRG does not emit any strong odors that might affect individuals with environmental sensitivities. GRG is stable and nontoxic, so those who own homes, resorts, casinos, restaurants, and retail stores can feel good about using it in indoor environments.
  • Glass Reinforced Gypsum is a cost-effective choice: GRG elements are typically a good investment from a financial perspective. They do not typically require extensive maintenance and regular repairs and are not susceptible to mold, insect infestation, rot, rust, or corrosion like some other building materials. In addition, the appearance of GRG elements can be completely changed by adding a new coat of paint. Finally, fiber reinforced gypsum is a much more affordable material than some of the materials it can replicate, including marble, limestone, and gold.
  • Mouldings
  • Ceilings
  • Columns
  • Light coves
  • Bas Relief
  • Domes
  • Bath Tubs
  • Capitals
  • Fireplace Surrounds
  • Medallions
  • Custom shapes
  • Vanity Tops