Things You'll Need

Instructions

1

Measure your outdoor bar to determine the size needed for your bar top. Determine the thickness you need as well. Concrete countertops are typically 1 1/2 to 2inches thick, according to Concrete Countertops (concrete-countertops.org). Use your table saw to cut your particleboard to the appropriate sizes for your concrete form. Uncoated particleboard will give you a rougher finish than melamine-coated particleboard.
2

Fasten the pieces of particleboard together with a brad nailer to create your concrete form. Run a caulk line around the interior joints of the form and smooth the caulk out with your finger. This helps produce a smooth edge to your concrete bar top.
3

Select a premixed concrete that is formulated specifically for countertops, and mix the concrete according to the manufacturer's directions. If you expect your outdoor bar top to be subjected to excess stress, consider reinforcing your concrete with wire mesh or fiberglass reinforcement additives. Make sure the dry powder components of the premixed concrete are mixed thoroughly and completely wet. Consider adding a concrete color additive to complement your outdoor decor.
4

Set your concrete form onto a solid surface. Check the form with a level, side to side and front to back. Adjust the form with shims until it is perfectly level. Pour the concrete mixture into the form and distribute it evenly until the form is completely filled. It is common for the concrete mixture to trap air inside the form when it is poured. Tap on the sides of the form to help the air bubbles rise to the surface.
5

Allow the concrete to cure according to the manufacturer's recommendations. Cover the surface of the wet concrete with a sheet of plastic while it cures. You may need to mist the concrete with water to help keep it moist. Be patient. Different varieties of concrete can take up to several days to properly cure.
6

Remove the plastic sheet once the concrete bar top has completely cured. Pry the long ends of the frame away from the short ends. Apply pressure against the frame, not the concrete, to keep from marring the surface of the bar top. The frame should come away cleanly, but if it is stuck to the concrete, use a plastic putty knife to pry the concrete from the form. Turn the concrete bar top over and set it onto the outdoor bar.