The polished beautiful quartz, marble or granite countertop that you install in your kitchen or bathroom undergoes an extensive process of stone fabrication to achieve the finished product. It is remarkable just how much occurs during this process and how important it is to getting the most from your countertop for years to come.
This fabrication process is done by a stone fabricator, which is a very specialized person. In some cases the granite supplier also specializes in stone fabrication and everything can be done at their shop prior to being delivered to your home. The convenience of one-stop shopping can lead to having more control over the entire process.
On this page, we will explore the steps between slab selection and countertop installation, otherwise known as the fabrication process.
Inspecting the Slab
In this first step, the fabricator will inspect your chosen slab(s). Stone, being a natural product often contains characteristics indigenous to that particular material, similar to how individuals may be born with birthmarks. Some of these characteristics include dry seams, black spots, polyester resin fill, pits, and natural directional veining, feldspar or mica conglomerates (knots). Often times, these marks make the stone what it is, unique and beautiful. On occasion, a customer may find certain characteristics unacceptable and the stone fabricator will work to avoid those during templating and fabrication process.
Prior to templating, a final inspection is made of the stone, identifying any areas unacceptable to the customer, or areas that are more severe than the normal characteristics described above. The fabricator will mark those areas and work to avoid those during templating, while balancing the effort to minimize waste and therefore cost.
Once the slab is inspected, it is then laid out and the previously created templates are arranged on the stone to ensure the best appearance of vein texture and color. The templates are also arranged to ensure appropriate flow for the various countertops in your layout. As an example with an L shaped countertop, or a countertop and an island that is parallel or perpendicular, you want to ensure the overall flow of the countertop pattern will work in your finished project. This natural beauty occurs more often in natural stone than in quartz, making this process especially important with granite or marble. This is where an experienced templater is key, it is a mix of experience and artistry. A beautiful countertop is just that, a piece of art, and you want it to be the focal point you are anticipating. For more information on the importance of templates in your project, see our article on templating and seams.
Cutting The Stone
The stone is then cut using either a water jet or a bridge saw. Historically, the bridge saw has been the favored tool, however in recent years the “saw jet” which is a combination of a water jet and saw has come into play.
The bridge saw cuts with a diamond segmented blade, and cuts at a feed rate of approximately 7 feet per minute. The water jet cuts with high pressure water with garnet particulate suspended in the water at a feed rate of 1 foot per minute. You are probably asking, who would cut with a water jet? The benefit of the water jet is that it can cut circles, radius’, or any intricate pattern, where the bridge saw cuts only straight lines.
Recently, a more specialized tool has come to the marketplace. A saw jet, which has a saw head and a water jet built into it. You program the saw jet with the parts you need cut, it then determines where to use the water jet and where to use the saw, giving you the best productivity of both worlds.
Once the pieces are cut from the large slab, those pieces are forwarded to a CNC machine and with the help of a vacuum lifting system, the granite countertop pieces are then fabricated.
In this phase of the stone fabrication, the cutouts for your undermount sink, cooktop, or holes for faucets are all made. The first step is cutting the stone to approximately 1/16 of an inch of its final size. Then, the CNC (Computer Numerically Controlled) machine is programmed to know the size of the stone or stones on the table. You can put multiple pieces of stone on the table and work on them together. The CNC machine is then programmed to know where the stones are located and what to do to each of those pieces. Since every stone has different working characteristics, it is key to have an experienced and knowledgeable CNC machine operator. It is truly a job where artistry and technology meet to produce the optimal finished product. Some stone materials require the CNC machine to move more slowly, some require stone to be entered in a certain way. Without this industry experience, the fabricating process may not produce the best end result we are looking for as consumers.
Once the holes are cut in the granite the edge is shaped by the CNC machine before the countertop is taken to final polish. There are a variety of stone edges to choose from, but the versatile CNC machine can produce any edge you select. For more information on the variety of edges, please see our article.
Strengthening the Stone
This step is specialized and may not be done by all stone fabricators. When you cut out the templates, you end up with a few stones that have thin rails of granite, for instance behind or in front of a sink or cooktop. By nature, those thinner pieces are not as strong as a larger surface area of stone. In the early 2000’s Great Lakes Granite and Marble conducted a study to find the best method for increasing the flexual strength of stone, specifically to reinforce this thin area. They tested various methods, working with the Marble Institute of America, and found the threaded rod technique described below to be the most effective.
In this step, rod slots (grooves in the granite) are cut and threaded rods are inserted into these grooves and encapsulated in high strength epoxy. When this process was studied, it was determined that this step increases the flexual strength of the countertop in that area by 400%. We should never be standing on our countertop, but I know I’m guilty of doing it to reach things in that high shelf, you wouldn’t want your stone cracking because this important step has been left out.
It bears mentioning that natural stone is extremely strong, approximately five times more than concrete. Even though different stones have various working characteristics, once installed in your home, the stone will likely outlive any kitchen you install it in. Understanding these characteristics and working within them during fabrication is key to ensuring your finished project is made to stand the test of time and use.
We are approaching the end of the process here, polishing the stone. When the granite arrives to the fabricator from the quarry, the face of slab is already polished. Typically the granite face is not polished or changed at the fabricator’s shop. What does need polished, however, is the edge. Recall during the fabricating step the CNC machine created the countertop edge you selected for your project.
Regardless of the edge, it will now go through a 7 step polishing process. The industry standard is to use diamond polishing pads of increasing grit from 50 to 3,000 to polish the edge. Think of sandpaper in increasing grit to visualize how this process works. The CNC machine first starts with a diamond polishing pad of 50, then 100, 200, 400, 800, 1500, ending at 3,000. The CNC shapes and polishes at the same time, leaving the edge shaped and polished. Similarly, if your granite is ever scratched or damaged, this process is used to repair it.
During this step, the edges of the stone ground to remove the microchipping and achieve the best and tightest seam possible. This gives you a finished product where the seam should fit nicely together, not drawing attention to it. For a closer look at the seam phantom process check out this video.
We are coming to the end of the fabrication process. Granite is naturally 90% impervious to moisture migration. By applying one coat of sealer, we take that rate up to 95-97%. Both the edges and face of the stone are sealed during this step. Since sealer doesn’t degrade in an interior setting (like your kitchen or bathroom) it is pretty much a set it and forget it step. You may want to re-apply sealer in about 10-15 years. For the re-application, you can pick up a great sealer at your local home improvement store and apply it yourself.
Quality Control & Hand Finishing
The final step in the process is inspection of the stones. The stone fabricator will ensure the edges are uniform around all sides of the stone(s). Then they will be reviewed from multiple angles to make sure the light is bouncing of the edges uniformly, and the color of the top of the stone and the edges match perfectly. At this point, we have a finished product ready to be installed in your home.
Stone is truly a piece of natural art, and following this extensive process ensures that your finished product is a beautiful focal point of your project. Mixing experience, technology, tools and artistry is key to a stunning end result.