All of the slabs are precast in our shop and fully finished and sealed prior to installation.
When it comes to concrete countertops, there are two basic processes: cast-in-place and precast. Cast-in-place involves building forms and pouring concrete in place, directly on the cabinets. While this avoids the hassles of transporting heavy slabs, it does tie up the site for many days (or weeks), and it involves a messy process. In addition, cast (or pour) in place provides fewer options and less control over the finished product. Generally, the only finish available is a trowelled surface, which is either acid stained or colored with pigments. The quality of the concrete, the finished appearance and ultimate performance of the countertop are all hampered by the fact that it’s all being done on site under a rushed time schedule.
Precast concrete, on the other hand, moves all of the processes off site into a controlled environment. In the structural engineering community, it is well known that precast concrete is superior to cast in place concrete, mainly because tighter quality control can be exercised. Curing, which is a critical step that is commonly misunderstood, can be closely monitored. Moving the process to a shop allows greater flexibility in terms of the look of the concrete. Glass, stone and other objects can now be embedded; these require extensive wet grinding with diamond power tools to reveal the embedded objects and hone and smooth the resulting surface.
There are 2 methods of precasting: wet cast and glass fiber reinforced concrete (GFRC).
Wet cast uses a more traditional concrete mix of sand, aggregate and cement poured into forms. Our formula uses specialized admixtures to achieve the ultra-high surface quality needed for interior kitchens and bathrooms. We use local ingredients whenever possible.
Because of our education with The Concrete Countertop Institute, we are able to properly reinforce wet cast concrete to prevent cracking. Proper steel reinforcement is essential to combat the large stresses placed on a long, thin slab of concrete such as a countertop.
GFRC is concrete that is structurally reinforced with a large loading of alkali-resistant glass fibers instead of with steel. It is built up in 2 stages: a thin “mist coat” that is sprayed into the forms and provides the surface appearance, followed by a very fibrous “backer coat”. GFRC is extremely strong, flexible and light compared to wet cast concrete.
Rockface Concrete Artisans will work with you to determine which type of concrete is best for your project, depending on the look and shape you want to achieve.