Concrete Countertops: Slab or Overlay?
Hard to believe that concrete used to be thought of as just a utilitarian building material. Edgy and modern, concrete now plays a starring role inside the most stylish homes. Homeowners love concrete for its beauty, versatility, and strength. One of its many uses is as functional, elegant countertops for kitchens and baths. There are two different processes for creating concrete countertops -- slab and overlay. What are the pros and cons of each?
Concrete Slab Specs
Slab-style concrete countertops are customizable in terms of length, width, shape, and layout. You can add decorative edge detailing or convenient features such as a built-in drain board or an integral sink. The concrete's minimum thickness should be 1 1/2", which means that it can be rather heavy (about 18.75 pounds per square foot) unless you use glass-fiber-reinforced concrete (GFRC), a strengthened concrete that may be used in a thickness of only 3/4".
Concrete Slab: Cast-in-Place vs Precast
It is possible to pour cast-in-place slab concrete countertops onto the base cabinets on site. When you hire a concrete contractor, this process permits him to produce smooth, seamless counters with beautiful coloring effects and artisanal hand finishes, using a trowel and a great deal of skill. Allow 1-2 days for installation, a week or more for the concrete to cure, and several days after that for polishing, staining, and sealing.
You may prefer to order precast counters, made using a customized template and installed in less than one working day. Precasting means that you will be able to use your kitchen and bathroom concrete countertops ASAP, with a minimum of disruption to your household's routine. The main disadvantage, though, is that a precast countertop will be heavy and difficult to maneuver.
In both cases, an experienced professional is required to install the concrete countertop.
An overlay is a thin layer of concrete adhered to an existing countertop that has become worn and/or outdated. Concrete may be overlaid on ceramic tile, Formica, granite, laminate, marble, solid surfaces, or wood. The complete application process, including custom coloring and sealing, takes 2-3 days, plus an additional day for curing. It's possible to install concrete overlay countertops as a DIY project if you're very sure about what you are doing. (Otherwise not only the looks, but also the quality and lifespan of your counters may be compromised.)
Concrete overlay countertops offer a huge advantage. They require much less material and eliminate the need to tear off and haul away your old counters, making their installation both convenient and green. In addition, they are much lighter in weight (about 1 pound per square foot) and less expensive to install than conventional concrete counters.
Some General Concrete Countertop Facts
Durable concrete countertops are suitable for interior or exterior use, such as in an outdoor kitchen. They are extremely versatile and can be finished in any one of an enormous variety of colors, textures, or faux finishes. Alternatively, an attractive, unusual aggregate might be added in, for example, sea glass, pebbles, mica flakes, or glitter.
On the minus side, concrete countertops are known for a tendency to develop hairline cracks -- which, however, do not affect the structure. With advanced concrete technology, cracking is becoming more and more rare. In terms of maintenance, the counters must be sealed to protect against moisture. You will also need to avoid exposure to acids (like wine or lemon juice) and abrasive cleaners. Cutting boards and trivets should be employed to safeguard against knife cuts and hot pots.
Concrete's main ingredient, cement, is produced by heating limestone, which results in gas emissions. However, new ingredients, mostly carbon-neutral industrial waste, are being used in many concrete mixes to make them more environmentally friendly.
Laura Firszt writes for networx.com.
Updated March 28, 2018.