Detailed instructions for making concrete countertops for your kitchen, bathroom or outdoor space
Photo by Concrete Countertop Institute.
Many homeowners are taking advantage of concrete’s versatility when seeking new countertops for kitchens, baths, bars, or outdoor entertaining areas. Skilled do-it-yourselfers, especially those with a little concrete experience under their belt, can also benefit from lower costs by tackling a basic countertop project themselves.
Concrete countertops are made one of two ways: pre-cast or cast-in-place. Although each method has its advantages, for most basic DIY projects, pre-cast is usually the best choice and that’s the method we’ll focus on here.
(See below for more on the differences between the two methods.)
These materials and supplies are readily available at your local Home Depot or Lowe's, online at Amazon, or can be found through our supplier directory.
Using 100% Silicone Caulk to Form Concrete Counters
Fu-Tung Cheng shows you how to use caulk during the countertop mold-making process.
If you’re a first-timer, it's a good idea to make a trial run on a smaller project to practice with mix consistency, color, and finishing techniques. Follow these steps from start to finish for a poured concrete countertop:
Screeding concrete countertop. Photo by Nobel Concrete.
Pre-cast countertops are poured, cured and finished off-site, in your workshop or garage, and then moved to where they’ll be installed. One big advantage to this method is that the countertop is built, cured, sanded and finished out of the way, without disrupting the use of your kitchen or bathroom — or creating a huge mess. Also, you won’t have to remove your existing countertop until it is time to install the new one. However, concrete slabs are extremely heavy (a 2 x 3-foot, 2-inch thick slab weighs approximately 145 pounds), requiring extra help to remove them from the form and install them.
Cast-in-place countertops are, you guessed it, poured right where they go, with the forms built on top of existing kitchen or bar cabinets. The building process can be messy, with wet concrete, sanding, and finishing all being done right there in your kitchen or bath. There’s also the inconvenience of not being able to use your counter until it is finished. Also, if anything goes wrong, say the concrete doesn’t set up correctly or coloring isn’t uniform, it’s much harder to start over. This method does have advantages, like being able to cast longer runs without seams, and there’s no transporting a heavy slab for installation. Also, larger or odd-shaped pieces that might not fit through doorways are already in place.
Countertop concrete mixes are specially formulated, high-strength mixes - essential for countertops due to their relatively large, yet thin, construction. Countertop mixes should reach a strength of 5000 PSI or higher when fully cured; compared to regular concrete that runs about 4000 PSI. Countertop mixes also contain additives that make it flow better into tight corners and cure quicker to release easily from the form in as little as 18 hours.
If you want to take your concrete countertop a step further with custom color combinations, adding features like drain boards, butcher block, integral sinks; or including embedded stones, glass, tile, or inlays, you’ve probably moved out of the DIY realm and should contact a professional contractor.
More information on Concrete Countertops
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