Choosing the Correct Countertop Slab Thickness

Choosing the correct thickness for your kitchen or bathroom countertop can feel like a minor decision, but in fact, it is one of the most important decisions you will make when selecting new granite or marble countertops. The thickness of the slab affects the pricing, installation method, and resistance to breakage. Most granite and marble slabs are available in either 2cm (¾”) or 3cm (1-1/4”) thick. Slabs that are 3cm thick are a better value in the end than the 2cm slabs. In addition to the technical reasons, 3cm material has a better looking edge since the profile can be fabricated with more detail without having to laminate the edge. A laminated edge is where a thin strip of the same material is applied underneath the perimeter of the countertop before the profile is cut. This treatment is used regularly on 2cm countertops to make them appear thicker, but the negative aspect is that the seam between layers will be visible.

It is common to assume that 2cm material is less expensive because it is thinner than 3cm, but that is a myth. It is true that the material cost is lower when comparing slabs, but the handling and fabrication costs are the same as 3cm material since the process is the same regardless of thickness. Even though 3cm slabs weigh more, 2cm slabs cost the same when handling the material because it requires greater attention and care to prevent breakage. Granite and marble countertops that are 3cm thick are strong enough to support their own weight when installed on cabinet bases. Countertops that are 2cm thick usually are installed on a 3/8” plywood decking to increase its strength and resistance to weight.

Marble countertops that are 2cm are more prone to breakage because it is a softer stone. It has become a popular choice for bathroom vanities because it has a “lighter” appeal both in color and thickness. With the proper care and attention to maintenance, marble is best suited in the bathroom. Granite slabs that are 3cm thick are the best choice for kitchen countertops because of its strength and resistance to staining. When the edge profile is solid with no seams, it gives the countertop a higher value and wears better in a high-utility area such as a kitchen. Another benefit to using 3cm material in the kitchen is that it can withstand overhang clearances up to 12” with either hidden or decorative supports. This is especially useful in an eat-in kitchen where there are bar stools along the cabinet.