The Benefits of Using a GFRC Mix for Countertops
What is GFRC? Does the material offer any advantages when used for concrete countertops?
Answer:
GFRC, or glass-fiber-reinforced concrete, is typically sprayed, much like shotcrete, but the mix design is different. Typically a GFRC mix consists of a large amount of cement, fine sand, and a very high loading of alkaline-resistant (AR) glass fibers. GFRC often has a low water-cement ratio (in the range of 0.33 to 0.38) and relies on acrylic polymer for early strength and high flexural strength.
GFRC can be spray cast into structural shells as thin as 3/4 to 1 inch thick. This cuts weight, one of the prime reasons to use GFRC. Some people use GFRC for concrete countertops because the material makes it much easier to design, make and install large, complicated elements by significantly reducing weight and by allowing for much simpler mold designs (the molds need only be one-sided rather than two-sided, as for wet-cast techniques).
Unlike conventional concrete that relies on steel reinforcing, GFRC relies on the high dosage of structural glass fibers and the polymer to create a strong composite. Although it is made with portland cement, it behaves differently from ordinary concrete. And some people think that GFRC looks and feels different than ordinary concrete, so be sure to show clients what the material looks like.
In addition to requiring AR glass fibers and other expensive materials, GFRC also requires special equipment for spray application, such as a hopper gun. So for simple, flat countertop slabs, the benefits of GFRC may not outweigh the costs. But I feel that for large, complicated designs, GFRC offers tremendous advantages. It is worth having in your “bag of tricks,” especially as you take your business beyond plain countertops.

