DIY Concrete Countertops

I built the large kitchen countertops for my vacation rental with this method, and later a small ensuite countertop with a vessel sink.

First the forms must be built using ⅝ inch melamine for the base, and ½ inch melamine for the sides. The sides should be 1.5 to 2 inches tall (add the thickness of the base melamine so the sides can be attached to the edge of the base with 2” brad nails).

Any holes for faucets or drains should be marked on the melamine and then an appropriate diameter segment of abs or poly pipe attached with a bead of silicone.

The inside corners and edges should then be caulked with silicone. This will be the top edge of the counter so take care to get a clean caulk line.

PSI-6000 concrete mix is then mixed with water and poured into the form. This is a high strength bagged premix - it has the cement and aggregate - just add water and mix well. No need for any sort of release agent - the concrete won’t stick to the clean melamine or silicone. There is also no need for rebar or mesh but it is recommended, especially in narrow spans. Tap the edges of the form with a hammer to get the air bubbles out, then let sit to cure. I let them sit for about a week before removing from the forms, misting them with water occasionally. Concrete hardens as it dries, and the slower and more evenly it dries the harder it cures.

Once the concrete is cured, carefully remove the melamine form. The countertop surface should have a very smooth finish requiring little or no other sanding or buffing. Any bubble holes can be filled by skimming some repair mortar and sanding flush. Several coats of concrete sealer are then applied, then a few coats of wax finish. The counters are then conditioned with wax every so often.