Steps to Building a Concrete Countertop
- 1). Measure the space for your countertop, making note of the length, depth and width of the desired countertop.
- 2). Use the measurements to build a form constructed from 3/4-inch melamine to hold the concrete as it cures. The melamine is strong enough to hold the concrete while possessing a smooth side that will not stick to the concrete. Cut the boards using a table saw according to the measurements taken earlier and assemble the boards into the form needed using a wood screw every 4 inches along the joint.
- 3). Place a strip of masking tape along the inside joint line of the counter's form bordering the joint from both sides. Fill the joints with black caulking and then smooth the caulk with your fingertip. The caulk will prevent the concrete from the countertop pour from seeping between the joints, creating lines in the corners of your countertop. Pull off the masking tape to create a smooth joint edge and wait overnight for the caulk to dry.
- 4). Measure the length and width of the base of the countertop form and then cut a sheet of steel mesh one inch less on all sides than the measured size with a pair of tin snips. Dip steel mesh in acetone and scrub the surface of the mesh clean on both sides.
- 5). Mix low-slump concrete in a bucket with an electric drill containing a paddle bit attachment. Add acrylic fortifier to the mix to increase bonding between differing concrete mix types. Add any aggregates or colors to the mixture as well. Place piles of the low-slump concrete evenly throughout the form about every 5 inches and half as high as the form is deep.
- 6). Mix pourable concrete in a wheelbarrow, adding aggregates or concrete color to match the low-slump mixture. Fill the countertop form with the concrete mixture to the level of the cones.
- 7). Place the sheet of mesh onto the poured concrete, supported by the low-slump cones. Make sure the sides of the mesh are all 1-inch from the side of the form.
- 8). Fill the remainder of the form with the pourable concrete. Smooth the surface of the concrete with a concrete float.
- 9). Vibrate the concrete within the form by placing a sander without sandpaper attached onto the side of the form and moving it along the form's edge.
- 10
Drag a wood screed along the top of the form in a back and forth motion to smooth the surface of the concrete even more. - 11
Cover the countertop form with plastic sheeting to prevent it from drying out too quickly and wait 10 days for the concrete to cure. - 12
Take the plastic off the form and wait 10 more days to complete the curing process. - 13
Remove the screws securing the form together and pull the form away from the countertop so you can transport it to the installation site.
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