We’ve talked about concrete countertops here before, but here are the actual steps to do it (an overview that will give you an idea what you are in for, when you decide to take on this awesome home project!) Remember this is going to take time: if you are at all weary of your abilities to work confidently on a DIY-style project, then keep the countertop simple—oftentimes simple looks best anyway, looks the most modern or elegant.
First, you are going to create a mold. Measure the existing countertop (if the countertops are missing, then measure the tops of the cabinets where the counter top will sit). You will want to transfer those measurements to a piece of melamine particle board—there are other materials that work—and cut out the dimensions (a circular saw works well).
These dimension will need to be exacting, and remember to cut out the sections from the particle board where the sink basin will sit. You will then need to build the sides of the mold, the edges which will contain the concrete from spilling out.
Assemble the mold—doing the work atop a workbench or over two sawhorses will greatly help with the speed of putting it all together, and your back will thank you). Then build a heavier-duty support frame around the mold. The concrete is heavy and its weight will push out against the mold, and you don’t want the mold buckling.
With the mold built you are ready to mix and then pour concrete into it. As with any concrete project make sure you pour the concrete well, and compact it well, so there arent any bubbles, any potential pockets which could lead to a weakness in the countertop later.
When the concrete is dried, remove the mold. Sand down the surface of the countertop—orbital sanders work well for this job. Clean the countertop with a damp rag after sanding it.
Finishing the countertop involves etching the countertop with an acidic solution, then washing the countertop and applying a sealer. With the sealer in place, simply put the countertop onto the cabinets and install it.
If you have any questions about building countertops (this was just an overview) call the concrete professionals at Shotcrete Montana.