How to Make Concrete Counter Tops

Learning how to make concrete counter tops is not an easy task, but the results can be spectacular. Concrete counter tops are an inexpensive alternative to granite, but are best used in simple applications like islands and straight counters that limit the formation of cracks.

Learn How To Make Concrete Counter Tops

• Fabrication location. Concrete counter tops can be formed separately or in-place. In-place installations are appropriate for small counter tops like vanities and islands, but larger counter tops will benefit from the room an outdoor or garage location will provide. Just remember that concrete counter tops can weigh as much as 20 pounds per square foot-provide for plenty of help when it comes time to move your finished counter top!
• Forming an opinion. The basic form for your concrete counter top should be made from particleboard faced with a layer of melamine. The melamine will be easy to release and gives the concrete a smooth surface. Openings can be created using various materials. Holes for pipes can be created using short sections of PVC. Sink openings can be created using a melamine fence or with a piece of Styrofoam cut to the appropriate size and fastened in place. Cover exposed absorbent surface like wood or foam with a layer of electrician's tape.
• Mixing concrete. Concrete should be mixed with as little water as possible to give the finished product extra strength. Carefully measure liquid ingredients (especially dye) to insure a consistent texture and color. Adding two quarts of Portland cement to a 60-pound bag of concrete will add even more strength.
• Calling in reinforcements. Concrete should be reinforced to limit stress fractures. Wire reinforcing, 3/8" rebar and polypropylene fibers will all help keep your concrete counter top strong. At a minimum, metal reinforcements should be used in the narrow spaces between any sink voids and the counter edges.
• Adding layers. Poly-fiber concrete has a fuzzy surface that makes is appropriate for internal use only. To pour your concrete counter top, first pack the edges with about an inch of regular concrete. Fill the middle with a layer of poly-fiber concrete and then top with a surface layer of regular concrete. Be sure to pack the concrete in tightly with a float to eliminate any air bubbles.
• Surface features. Using a length of 2" metal channel, strike (smooth) the surface using a sawing motion along the entire length of the concrete counter top. After the concrete sets for about two hours, trowel it smooth in a few brief sessions. Overworking the surface will bring the aggregate in the concrete to top, creating an uneven surface.
• Drying time. Once you've leveled and smoothed the surface, cover the counter top with a damp cloth and allow it to dry for 48 hours up to 4 or 5 days. Carefully remove the forms using a small pry bar to loosen the joints.
• Sanding smooth. Wearing a respirator, smooth sharp edges and corners using a sander equipped with 100-grit sand paper. Fill any voids along exposed surfaces with a cement, latex additive and dye. Allow this skim coat to dry completely before continuing. Sand the edges of the counter top with 180-grit sand paper until smooth.
• Sealed to perfection. After installation, seal the concrete counter top with a commercial concrete sealer. Buff with a non-abrasive material after drying. Wipe the counter top down and apply a clear acrylic finish and buff using a drill with a buffing pad attached.