Glass fiber reinforced concrete ( GFRC ) is a proven engineered composite building material consisting of Portland cement, aggregate, water, glass fiber reinforcement and additives. The glass fibers reinforce the concrete, much as steel reinforcing bars do in conventional construction. The glass fiber reinforcement results in a product with much higher flexural strength than normal concrete, allowing its use in thin-wall casting applications.

For building panel construction, GFRC castings are manufactured by spraying a series of layers of polymer-concrete material with glass fiber reinforcement in a female mold. A steel frame is bonded to the casting, allowing the panels to be installed by bolting or welding the frame to the building's structural steel. The flex-anchors, which connect the skin to the frame, allow movement of the skin relative to the supporting structure.

In the late 1960s, GFRC was first successfully produced in England. The key to success was the development of alkali-resistant glass fibers, capable of resisting the alkali attack that occurs when the fibers are mixed with normal hydrating Portland cement.

In 1980 the product began to be used in the USA. During the 1980s and 1990s, GFRC became widely accepted, and the industry has grown dramatically.

GFRC has made a major contribution to historical restoration because of its fine texture, allowing almost perfect replication of building ornaments and terra-cotta. Its very low shrinkage allows molds to be made from existing structural ornamentation, then cast in GFRC to replicate the original designs.