Concrete countertops are horizontal work surfaces that are fabricated from natural materials. Concrete has been a popular material in construction since the Roman empire. Traditionally, concrete has been used for exterior surfaces on grade and structural assemblies in buildings. Recently, this hardened mixture of cement, sand, gravel, and water has become a new material option for residential and commercial countertops.
This strong, versatile material can be precast in a mold or cast on site and is available in any color or shape. Precast countertops are poured in a controlled environment and shipped to site. Some contractors prefer to cast concrete on site, so they can form the countertop to the specific job criteria. In either method, concrete ingredients are mixed , poured over reinforcing in a mold, vibrated, smoothed, sealed with a penetrating sealer and allowed to cure. The curing period for concrete takes about 28 days, at which point the molds are removed and the surface is mended to remove any inconsistencies. A 10 square foot concrete countertop can weigh as much as 200 pounds and requires 3/4 inch plywood cabinet construction to support the load of the work surface.
The overall size of a seamless concrete countertop is only limited by shipping and manpower during installation. Concrete countertops are typically 1 1/2 to 2 inches thick, but can be thicker, if a more substantial appearance is desired. Edge detailing is usually similar to that of other countertop materials, although different edge treatments can also be created using custom molds. The use of stains, pigments, aggregates and coatings allow for a variety of appearances, textures and finishes. Surface finishes are pressed, troweled, or ground, or the surface can be polished to mimic a quarried stone countertop. Concrete countertop fabrication allows for hard or soft material inserts, inlays, drainboards, trivets, glass, etc., which can be formed or embedded on the top surface, allowing for personal creative expression.
Over time, concrete countertops can develop hairline cracks. Due to the porous nature of the material, concrete can stain if a proper sealer is not regularly applied. While concrete countertops are resistant to heat, it is recommended that a heat pad always be used in order to eliminate any possibility of discoloration. Priced similarly to solid surface countertops, concrete countertops are commonly used on bar top surfaces and in outdoor kitchens, indoor kitchens and bathroom vanity surfaces.
See also: Countertops 101