Concrete

 Uses: Kitchen/Laundry Room Countertops, Flooring, Walls,
 Shower Walls/Floors/Enclosures, Tub Decks

Although concrete is a hardened mixture of water, cement, and sand or gravel, concrete countertops bear no resemblance to garage floors or roads.

Concrete countertops are made of cement, lightweight aggregates, and a other additives such as fiber reinforcement, silica fume pozzolan, and acrylic.
 
In order to prevent cracking, reinforcement such as structural steel, wire mesh, fiberglass, and/or fibers is used.
 
Depending on the installation requirements, more than one type of reinforcement may be used.

In addition, concrete's flexibility makes it an increasingly popular choice for drainboards, and backsplashes in complementary colors and textures.

Concrete countertops are made by thousands of small independent fabricators scattered throughout the country. Each slab is hand cast so none will be exactly identical. Countertops are either pre-cast in a shop or built on site.

The contractor will use whichever method he/she is most comfortable with. There are no industry-wide standards and no two fabricators make it in the same way. The type, method and number of coats of sealer are unique to each contractor

Some contractors still form integrated sinks made of the same material as the top just as it has been done for many years, but the more common sink is a flush-mounted stainless steel or cast iron model.

Characteristics
    
Appearance
Concrete countertops are a warm natural looking material. The surface of a properly finished concrete countertop is smooth and reflects light, although the use of chemical stains, coloring pigments, various aggregates, and epoxy coatings can give concrete the look, texture, and feel of quarried stone such as marble, granite, and limestone.
 
Veining, texture and color vary, and regular use imparts a warm patina to the surface over time.

The three most common types of finishes used for concrete countertops are:

o    Veined:
A diamond-impregnated grinding disk zigzags across the slab, producing marble-like veining in the background. While gently textured, the surface is smooth enough to roll dough or write a letter.

o    Trowel:
Obvious trowel marks and subtle variations of light and dark, resemble a European plastered wall. However, the surface is smooth and mostly monochromatic.

o    Terrazzo:
Glass or marble chips are added to the background, creating a two-toned mottled effect. Again, the textured look is seen under a smooth top surface.

·    Available Colors
Each Concrete countertop contractor offers their own unique selection of standard and premium colors. Numerous color options give homeowners broad choices for coordinating a surface with other colors and materials in a room. But asking the fabricator to try to match a color will always increase the cost, and color matching is not an exact science.

·    Seams are Visible
Seams in concrete countertops are visible and look similar to the seams in marble or granite.

·    Must be Sealed
In its natural state, concrete is porous and will stain. Concrete countertops are sealed with a surface sealer, such as epoxy, for water and stain resistance. Many contractors add conditioners to the concrete to make it less permeable and thus more stain resistant.
 
Many contractors recommend the application of a good water based liquid wax every nine months to a year.

·    Staining and Discoloration
Staining and discoloration can occur if the sealer is compromised from cutting or the application of heat (such as hot pots and pans).
 
For those who want the look of concrete without worrying about stains, solid surface is the answer.

·    Durable but not Indestructible
Concrete countertops often develop hairline cracks, which are too narrow to trap food and debris. The cracks tend to be non-structural and result from the natural shrinkage of the concrete.
 
Hairline cracks can be patched, but often look far more obvious than the cracks themselves. Most people prefer the aged appearance that this natural occurrence produces.
 
Depending on the density of the concrete, a blow from a falling heavy object may crack the surface or break off the edges. However, under normal use concrete countertops will last a lifetime.

·    Maintenance
Cutting on the concrete countertop won't hurt the concrete, but will damage the sealer, which can allow water and stains to penetrate the concrete. Cutting boards should always be used when chopping or preparing foods.
 
Concrete is very heat resistant, but avoid placing hot pots or pans on concrete countertops since the heat can damage or discolor the sealer or wax . Always use a trivet or hot pad on the counter. Some contractors will insert trivets made of stainless steel, brass, or copper in the countertop.
 
Do not use abrasive pads or powders on sealed counters. Clean with warm water and a non ammoniated, nonabrasive cleanser, or a stone soap.
 
·    Bacteria Resistance
A recent study conducted by the Hospitality Institute of Technology and Management, a St. Paul, Minnesota-based organization that develops educational materials and research for the retail food industry measured the bacteria-resistance capacity of six common countertop materials.
 
Each surface was contaminated with E. coli (nearly 2 billion of the microorganisms), washed and rinsed with soap and water and then sanitized with a vinegar-and-water solution. The results are shown in the table below.

Surface Microorganisms Eliminated by Cleaning 

Stainless        85,113,804 

Granite           79,423,823 

Laminate            498,884 

Ceramic Tile        293,765

Concrete               32,810

Wood                     2,080
   
Dr. O. Peter Snyder Jr., who conducted the study, says, "We hope our research will help consumers make healthy decisions when selecting a countertop surface for their kitchens."

·    Size Limitations
The standard concrete slab thickness is 1.5", although 2" slabs are common.
 
A 1.5" thick standard concrete countertop has an approximate weight of 18.75 pounds per square foot. (Granite is approximately 18 pounds per square foot.).
 
Lightweight concrete is available that is just as durable as heavier concrete.
 
A standard 1.5" thick, ten square foot (2'x5') countertop weighs nearly 200 pounds. Many contractors use 10' long or 20 square feet in area as their maximum size for standard pricing. Larger sizes will require seams.
 
Standard cabinetry will support the concrete slabs as the weight of the countertops is distributed over a large area.

·    Must be Professionally Installed
·    Expensive
Concrete countertops are a custom crafted material for high end use. Costs for a standard 1.5" thick countertop, including installation can range anywhere from $75 - $200 per square foot, depending on the area of the country.
 
Irregular or curbed shapes, 2" thick concrete, integral drain boards, custom edges, and backsplashes will increase the cost.