What Are Concrete Countertop Forms?

Concrete countertop forms are strips of strong plastic that create a perimeter structure for holding wet concrete. In the past, consumers requesting concrete countertops purchased precast slabs generated at a factory. Workers would transport and install the precast countertops at the consumer's home. The modern invention of concrete countertop forms allows a fresh concrete pour at the consumer's home, providing choice in design and countertop layout.

Forms are available in a variety of shapes, allowing the consumer to choose the countertop edge design. Some forms create a smooth, curved counter edge, whereas others generate a leveled staircase shape for fancy layouts. Concrete countertop forms must be thick enough to hold an ample amount of concrete during curing, and are normally about 1 to 3 inches (2.5 to 7.5 cm) tall.

A contractor installs concrete countertop forms using screws to fasten the forms to each edge along a cabinet's perimeter. The corners should be secured with duct tape, or other strong tape, to ensure that concrete will not leak out at the joint. Concrete is pressed into the form by hand. Hand pressing allows the workers to verify that the concrete has fully coated the form's shape.

Concrete easily cracks from temperature changes and excessive vibration. As a deterrent, contractors place thin rebar, or steel rods, across the countertop's surface after applying the hand pressed concrete. The rebar is typically positioned in a checkerboard fashion, preventing cracking by providing slight flexibility to the future concrete pour.

The final concrete pour must cover the rebar and fill the forms to their top edge. Workers use flat trowels to smooth the surface, which will become the working countertop after curing is complete. Once the concrete hardens, the contractor can sand any rough edges along the concrete countertop forms with a power sander or simple sandpaper.

The forms must be removed after curing. Form manufacturers commonly use plastic that resists concrete adhesion, but it is helpful to use a vibratory tool, such as a power sander, against the form's exterior to loosen the plastic from the cured concrete. The forms easily snap off after receiving the vibrating procedure, revealing the new countertop edge.

Concrete countertop forms work well for consumers who have a relaxed construction schedule. Wet concrete requires curing times that cannot be altered for a rapid construction pace. Consumers on a tight schedule may need to choose a precast concrete countertop which only requires installation time.