Can cast concrete crack?
Technically speaking, a countertop continues to cure for years after it is poured, so good mix design and proper curing are the keys to ultimate strength and integrity.
Admixtures (consolidators and plasticizers) that we use when pouring our concrete pieces yield a final product with a denser, less porous surface. These products make the concrete more workable when pouring, while reducing the overall concentration of water within the mix design. As we all know, too much water will weaken the integrity of any concrete product. As with marble and granite, concrete can chip if struck by a hard object. Vulnerable pieces like those with sink knock-outs are substantially reinforced and carefully transported to ensure the piece is not compromised.
Our mix design also includes micro fiber, 3/8” aggregate, and additional cement – all of which are the principal ingredients that give concrete its strength. Wire-mesh reinforcements are also used, making spans up to 10 feet long a possible application for any concrete project.
How many colors do you offer?
We offer 16 different colors for concrete countertops, vanities, fireplaces and décor. These high-quality pigments provide vibrant, stable, long-lasting, consistent and predictable colors. Our particular mix includes premeasured densifiiers and consolidators added to the pigment rendering a stronger, more impenetrable surface. Click here to see our color chart.
Are color samples accurate?
In order to achieve realistic color outcomes, our samples are all created in a controlled environment and poured when pouring larger sections. As all colors are based on the ratio of dye relative to the mix design, final products will be very close to the samples provided. Based on a number of variables, including the size of pour, cure times, and slight irregularities in the manufacturers products, we will not be able to guarantee that we will be able to provide exact color matches. If variations occur, they will only be slightly lighter or darker than sample provided, but we will always achieve the same hue.
How thick or thin can cast concrete be?
We prefer thicker reveals, from 2” thick and up, depending on the project – rather than thinner tops, as we like the sense of mass a thicker top provides. We can create the illusion of mass by forming a thicker reveal, while maintaining the 1.5” to 2” thickness all the way through. Our minimum thickness requirement is generally 1.5” – any thinner and the piece runs the risk of curling or experiencing additional stress that can cause cracking. Countertops tend to curl when they are toothin and/or if too much water is present in the mix. Secondly, curling also occurs when a countertop cures quicker than it should. The challenge of a thin countertop is ensuring the reinforcement material lies flat within such a narrow space such that it isn’t so close to the countertop surface that it creates a “ghosting” effect (a slight discoloration in the surface of the concrete along the lines of the wire or rebar). For thin pieces, we may make them in a moderate dimension–not too long or narrow, as this adds stress.
What is the difference between a fine grind and a medium to heavy grind?
With our refined forming techniques we are able to achieve a very fine grind, exposing very few fines (sands/aggregate) rendering as close to a solid color as possible. When we grind the surface of our countertops, we are taking off the cream layer to reveal the aggregate stones, which can vary throughout the country as concrete is regionally produced. Some people trying to achieve the medium to heavily ground look are happy with revealing the aggregates that come with the concrete. While others, trying to achieve a truly unique or custom look, will supplement natural aggregate with decorative aggregate, beach glass, or other decorative stones.
How much does cast concrete weigh?
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.) Standard cabinets will support the concrete slab as the weight of the countertop is distributed over a large area. Generally speaking, you don’t need to reinforce your cabinets or floor to support the top. However, if the supporting cabinets are single-wall or made of particle board, vertical plywood reinforcements may be necessary.
How do you seal your countertops/cast concrete?
Our preferred sealer is a professional-grade water based sealer which creates non-yellowing barrier coat to seal, protect and beautify concrete (thus, it a honed/matte finished, not a wet-look sealer). Epoxy sealers are available and do allow for more impenetrable surface protection. Acrylics are not as strong as epoxies and both tend to scratch, as they leave a build on the surface.
Are there things I shouldn't do with cast concrete?
As with marble or granite, we do not recommend cutting directly on a concrete surface, as it could result in scratches and gouges in the finish of your countertop as well as harm the blades of your knives. We recommend inlaying a marble, wood, or other type of cutting-board, as a safe alternative for cutting.
Concrete & Heat: Concrete is heat-resistant but is subject to thermal shock if a red-hot object is placed directly upon it. Like granite, the exposed area may flake or chip away if too much heat is applied. We recommend using trivets for hot cookware, to avoid these concerns.
Do concrete countertops stain?
Concrete has approximately the same porosity as marble. Currently, we are using consolidators and densifiers as part of our mix design to reduce porosity. Penetrating sealers are generally used on our surfaces, which now repel many liquids known to have caused staining in concrete in the past. When exposed to acids, including red/white wine, lemon juice, strawberries, and vinegar, countertops may stain (many times the sealer discolors yet the concrete is still protected). If not cleaned up right away, these materials and others like them may etch the surface as well. Ultimately, prevention is the best defense—be sure to wipe up any potentially acidic liquids like wine, vinegar and other substances like lemon or tomato juice immediately. When staining occurs, counters can be stripped and resealed as needed, though heavier stains/etching may not be remedial.
How do I clean concrete countertops?
Washing your countertop with mild soap and water is the best method of cleaning. Be wary of cleansers and scrubbing pads as they may have chemicals and abrasives that can harm, scratch, or etch the surface of your countertop. We recommend organic or mild cleansers. Ammoniated products (Bleach or bleach-based cleansers, Windex, and other harsh chemicals) should never be used on concrete. Dependng on the sealing application, surface polishes (like a granite polish), will give added protection and overtime, any areas with irregularities will re-emulsify and become a subtle distinction of age and character. This does not apply to acrylic or epoxy-sealed concrete. When using any product, we recommend testing in an inconspicuous area, to make sure it does not cause any unexpected results.
Maintenance: realistically, many owners only reseal their countertops once a year or less, and then some never do at all. Without upkeep and maintenance, your countertop will age and patina, but this is only cosmetic and will not affect the durability of your countertop. As long as you like the aesthetics of your countertop, the countertop itself can be virtually maintenance-free and provide many years of enjoyment.
Can you make a seamless integral sink?
If a client desires a completely unique or custom sink shape or design, we can create integral sinks, and we recommend this application more for vanities than in kitchens. The basin template can be created and fit to nearly any form using a rubber, fiberglass, or plaster mold, depending on application and style.
Our reservation to this technique in a kitchen application is that the wear and tear from everyday use (washing heavy pots and pans, pouring wine or acidic juices in the sink, etc.) can significantly impact the finish and overall appearance of the sink. We favor stainless-steel sinks in kitchen applications.