If you mention concrete countertops to people, most will think of horrible cement gray rough finishes that look like a sidewalk or driveway. In fact, with concrete kitchen countertops, nothing could be farther from the truth.
This material can be worked into many textures, and can be colored and detailed to suit any kitchen. The type of concrete used for countertops is different from what is used in construction, and the curing process is important.
The countertop is poured and set before delivery according to your designs. It is denser than granite, but still provides the same degree of stability through its weight and mass at about one and half inches thick.
Concrete is more dense when cured than granite or marble, and while granite consists of about 75% silicon dioxide, concrete is largely calcium oxide. The atomic weight of silica is 28 compared to the 40 of calcium, so concrete is almost 50% heavier than the same volume of granite.
The factory creates a mold and pours the mixture. You can have the sink included in the mold if you prefer a one piece unit - just like with Corian. This reduces the chances of bacteria and viruses getting trapped and accumulating in the joins and seams.
There are some potential drawbacks when using concrete kitchen countertops, one being its porosity. It absorbs moisture and can stain or easily discolor so it should be regularly sealed, just like granite, to prevent the normal kitchen liquids such as oils, greases and food colorants from being absorbed.
Be sure to use a contractor the plenty of experience with this type of countertop. It's not as simple as mixing a bag of cement from the hardware store. The critical aspects of a concrete countertop are the mix of cement, sand and water and any plasticizer and curing agent applied to increase the water resistance. These are very important, and a good company will know the best additives and ratios to use for the kitchen environment.
Concrete for this kind of application can be textured, veined, highly polished or totally matte, glittered by adding highly reflective dust to the mix or given a completely natural grain and texture by adding specific types of sand. You can be certain of one thing with concrete countertops: no two will ever be the same, even if made by the same person.
But like anything else, there are some weaknesses to be aware of with a this type of kitchen countertop. It is entirely possible for it to crack over time. And as mentioned already, staining can be a problem too. Sealants are not 100% effective against everything it might be subject to, but if done professionally, sealants can be very effective at blocking stains from all but the most abusive treatment.
This is not the least expensive option, but it is one of the most versatile in textures, shapes, sizes, and colors. And if you're looking for something unique, you can bet none of your neighbors have anything like a concrete kitchen countertop.