If you're planning a do-it-yourself concrete countertop, or contemplating hiring a professional for a pour in place project in your home, you'll need to take precautions to reduce health risks associated with several of the materials of concrete manufacture.
- Cement is a fine powder that easily becomes airborne. Since it hardens when moistened, it's important to keep it away from the moisture in your eyes and lungs.
- Aggregates may contain silica dust that can harm lungs.
- Fresh concrete is highly alkaline and can burn skin.
- Some pigments and acid stains contain heavy metals. The waste from these products is hazardous to the environment.
- Some products available to seal concrete contain solvents that are not safe for food preparation. Choose only food-grade rated sealants.
These materials must be handled with care and proper safety gear.
And don't forget that concrete is very heavy. You'll be moving hundreds of pounds of material in every stage of the project, from bringing home the raw ingredients, mixing them, pouring the concrete, and installing the finished countertop.
Making a small, simple concrete countertop is an achievable do-it-yourself project. Creating concrete countertops for an entire kitchen is a challenging undertaking, especially if you haven't worked with concrete before. Potential hurdles include:
- Variations in the concrete mixture produce a non-uniform product.
- Imperfections in your form will show up in the hardened concrete.
- Mixing, curing and finishing a concrete countertop requires space, time and a climate-controlled environment.
- Concrete countertop professionals rarely share their mixture formulas and trade secrets.
Even if you take an incredible amount of care in creating your concrete countertops, there are several things that could possibly go wrong. You may encounter ghosting, shadows of reinforcing rods that appear on the surface. This is caused by insufficient vibration of the mold. Grinding to reveal the aggregate may minimize the appearance.
The concrete countertops may also crack because of too much water in the mixture or evaporation of water in hot, dry conditions. Another pitfall may be efflorescence, a white coating that blooms on the surface of concrete. Water stains may occur from discolorations in the concrete due to water pooling under the concrete or seeping through the mold.
Even without holes, cracks or chips, concrete is very porous. But a well-fabricated, properly sealed concrete countertop should be resistant to moisture and free of pits or pinholes that can harbor bacteria. A 1999 study by the Hospitality Institute of Technology and Management shows that a concrete countertop's resistance to bacterial contamination when cleaned with dish detergent and water is similar to that of stainless steel, and superior to wood, laminate and tile countertops [source: Hospitality Institute of Technology and Management]. Cleaning with vinegar kills significantly more bacteria than cleaning with soap and water, but the acid in vinegar eats through wax sealants commonly used on concrete countertops.