Concrete countertops are becoming more and more popular due to their strength and distinct look. While the idea of a DIY concrete countertop might be daunting, it has never been easier! In fact, creating your own countertop is easy to do, and cheaper than hiring someone to make it for you! There is one trick we will share with you (see step 2) to get the best results that not many DIYers know. By following a few simple steps, you could be on your way to having that chic concrete countertop you have always wanted.
Quikrete Quick Setting Concrete from Koopman Lumber on Vimeo.
Step 1 – Prepare the mold and support frame
To start, you’re going to make a mold. First, measure the dimensions of your base cabinet or of the countertop you are looking to replace. If measuring the cabinet, add a few inches for some overhang. Melamine particleboards are the perfect material to make a mold out of. After figuring out the exact dimensions you need, cut the melamine particleboard into those dimensions. Then, cut out thin strips of the particleboard to be used as sides of the mold. Screw these thin strips into the base particleboard. Then, run a bead of silicone caulk along the inside of the form, filling every single crack. This will create a complete mold capable of holding concrete.
Since the concrete will be very heavy, you’ll have to create a support frame for the mold to make sure it does not break or crack. After creating the mold, add a support frame by placing several 2x4s under the form. Take 4 2×4’s, and place them tightly around the outside of the form while resting them on the 2×4’s that are underneath the form. Screw the outside 2x4s into each other, creating a tight support frame that should hold the mold into place while the concrete dries.
Step 2 – Mix the Concrete
This is where we teach you the most important hack we know; Quickrete Countertop Mix.
Quikrete is the ultimate concrete mix for countertops. To start mix your Quikrete mix in a wheelbarrow or similar container. An 80lb bag of Quikrete takes 3 quarts to mix properly. If we are adding liquid coloring, make sure to account for the extra liquid that will be going into the mixture. When mixing water into your Quikrete, stop when it looks like a thick oatmeal, and should hold it’s shape in your hand. Any more or any less and you might have a weak countertop, or it may not hold together at all!
Step 3 – Pour the concrete
Once the concrete is mixed pour it directly into the mold. As you fill the mold, the Quikrete Countertop Mix should flow and disperse easily, but may need to be moved around with your hands or a hand trowel. Make sure to pack down the concrete mixture as you go. Once the mold is full, smooth out the top with a hand trowel or other flat tool to create a level countertop. Then, you will want to use a mechanical vibrator, orbital sander, or even a rubber mallet to remove any air pockets from the mixture. Use these tools to shake the mold, releasing the trapped air. Keep at it for a few minutes or until there is no air breaking the surface of the concrete. Air pockets make the concrete weaker and easier to crack, so this step is very important. The Quikrete mixture will be stronger the longer it sits, here is a quick breakdown of its compressive strength over time:
Compressive Strength (ASTM C 109 Modified):
3 Days – 2,000 PSI (13.8 MPa)
7 Days – 4,000 PSI (27.6 MPa)
28 Days – 6,000 PSI (41.4 MPa)
For the strongest counters, plan this project in advance!
Step 4 – Remove the mold
After the concrete has cured, remove the mold and support frame from the concrete slab. To do this, unscrew the 2x4s that make up the support frame and remove them. Then, screw in a couple of 2-inch screws to each melamine side, and use the back end of a hammer to carefully remove the form from the countertop. Do this slowly and carefully, as the concrete could chip if you aren’t careful. After the form is removed, grab a friend or two and turn the slab over, exposing the side that rested against the melamine form as the top of the countertop.
Step 5 – Perfect the countertop
Then, remove any imperfections with a power sander. There could be a few imperfections, so just know that this step could take some time. Once you’ve sanded the slab, wipe off all dust and other particulates with a wet rag. Next, apply a USDA-approved sealant or covering with a brush, brushing in straight lines down the length of your new countertop.
Step 6 – Installation
Finally, we need to run a thick line of silicone caulk on the top of the cabinet. Then, place the countertop into position and press down on the caulk. Now, we can enjoy our beautiful, hand-crafted countertop!
Whether preparing food, enjoying a few drinks, or just entertaining in the kitchen, your hand-crafted concrete countertop will always be up for the job, just like you were when you made it!
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