The thickness and weight of concrete countertops depend on factors like the style of countertop, type of concrete that is used, and the desired thickness of your countertop. Concrete countertops are basically made of aggregates, cement, and additives like acrylic, fiber reinforcement, or silica fume pozzolan.
There are many different types of concrete, and they are: regular concrete, self-compacting concrete, shotcrete, no-fines concrete, cellular concrete, roller-compacted concrete, and asphalt concrete. These different types of concrete yield several levels of thicknesses and weights, but they cannot all be used for building concrete countertops. Most of them are used in building industrial structures like buildings and bridges which need stronger and thicker concrete.
Professional builders usually mix their own cement mixture specifically for concrete countertops. Concrete is sold in slabs that have an average thickness of about two inches. Thinner, one and a half-inch-thick concrete slabs can also be made, but they may not be as durable as the normal two-inch thick slabs. Concrete slabs can also be made thicker - as thick as six inches - for aesthetic purposes.
Thickness of concrete countertops
The normal household kitchen concrete countertop is made of concrete slabs that are an inch and a half thick. This thickness is just enough to provide ample support for normal food preparation activities done on the countertops. Aside from providing enough support, these concrete countertops are easier to maintain than thicker concrete countertops that require frequent sealing.
For non-traditional concrete countertops, a thicker slab is used for dramatic and aesthetic purposes. Thicker concrete slabs that look like they have a thickness of six inches actually do not. They only appear that way when they are looked at from the front. Their sides and center still have the normal one-and-a- half-inch thickness, but their construction creates the illusion that they are thicker.
Weight of concrete countertops
Generally, the thicker the concrete slab is, the heavier it weighs. Per square foot, the normal one-and-a-half-inch thick concrete slab weighs around 18.75 pounds. This makes it around a pound heavier than a granite slab. However, depending on the type of concrete used to make the slab, concrete slabs can weigh much lighter. Lightweight concrete is used to make concrete countertops lighter. However, this material is less durable and more prone to cracking.
How to support concrete countertops
Regardless of their thickness and weight, concrete countertops still need to be supported to make them more stable and durable. Like all other countertops, concrete countertops are mainly supported by the cabinets installed above and beneath them. The cabinetry underneath is usually enough to hold the weight of a concrete countertop. However, for thicker concrete slabs, braces or adhesive can be used to glue the concrete countertops in place. The use of additional support depends on the countertop design and the existing cabinetry.