How do I make concrete counter tops?
First you need to determine if your base cabinets can carry the weight. Concrete is heavy! You may need to reinforce before proceeding. Here are a few sites to get you started!
There are many more, just Google! You Tube has many tutorials too.
Yes base cabinets need to be made out of 3/4 inch plywood or at least 1/2 inch plywood. Cannot be chip board or masonite.
Ask This Old House has videos on You Tube.
Make sure that you seal them when finished, as concrete is porous and spills will percolate into the top and not be removable.