Do-It-Yourself Concrete Countertops
Building your own concrete countertops is something any do-it-yourself person can tackle. We decided to do all of our kitchen and bathroom countertops out of concrete and I think they turned out quite well and add to the rustic theme we were going for in our cabin. I'll walk you through each step of this process in the following pages.
Once you've decided to undertake this do-it-yourself project, you'll need to take surface measurements for each countertop and decide how thick you want to make them. We made ours 2.5" thick and they seem very beefy. I've heard of some people going 3" or more but that starts to get massive to move around.
STEP 1: Building Concrete Countertop Forms
Step 1 of do-it-yourself concrete countertops to build the forms. I know it is possible to do pour-in-place concrete countertops but we went with forms instead. The advantage to pouring the countertops in forms is that you get a very smooth and even surface when you are done and turn the concrete over. This flatness is difficult to duplicate with pour-in-place countertops which requires special diamond grinders/sanders and a lot more skill to get it right the first time. We used melamine boards from Home Depot to build the forms. Melamine board is 3/4" thick particle board laminated with a smooth white plastic finish on each side. They typically come in 4 x 8 ft sheets and run about $40 each.
Multiple concrete countertops can be formed on the same sheet of melamine as shown above. 1.5" screws can be used from the bottom to hold the vertical forms in place. I recommend setting the forms up on saw horses to allow access to the bottom for screws. Be sure to get enough support underneath however to keep everything flat...there will be a lot of weight when you put the concrete in.
We used rectangular sinks for the bathrooms which made the forms a little easier. You should purchase you sink ahead of time so you can fit it on your forms and make sure you have the desired overhang. The same goes for your facets. A wooden dowel that is the right diameter works great for the three facet holes. One thing you'll want to double check is the thread depth on each of your facets. Most are only made for a 1-2" thick countertop so you have to build an extra keep-out as shown above to account for that.
Once your forms are in place, you will need to run a bead of caulking around all the seams of the form. This will give you a slight rounded edge on your concrete countertops once they are complete. Also, wire mesh should be used to strengthen the concrete countertops. In addition to the wire mesh you see in the pictures above, we put a piece of 1/2" rebar along the top and bottom of each countertop. This adds the extra support across the bottom and top of the sink where the concrete is relatively thin.
Here's our forms for the main kitchen countertop along with the bar. For the kitchen sink keep-out we used a piece of left over metal fascia to make the rounded corners. It worked out pretty well. Since this is a do-it-yourself project, be creative. There are a million different ways to form your concrete countertop. Some people embed stainless bars and a slope to make dish drying racks..the list goes on.
Close-up of concrete counter kitchen sink form.
Top view of do it yourself concrete countertop - kitchen and bar forms.