As concrete countertops continue to grow in popularity for kitchen remodeling, clever designers are on the lookout for new ways to apply the techniques they've perfected. In this pursuit, many innovators in the field have identified the bathroom vanity as a great location for a concrete countertop. One of the leaders among them is California-based Fu-Tung Cheng. With the help of Mr. Cheng and his associate Jeff Osteen we designed and built a concrete vanity top for a HANDY project that appears in the May/June 2005 issue. Here is a complete sequence of photos that show how we made our concrete vanity. ?
We mounted the completed bathroom vanity top on a painted metal base
HOW TO CAST A CONCRETE VANITY
Step 1: Level the form on a sturdy worktable; then secure it to the table by driving screws (not too long) up through the tabletop and into the form.
Step 2: Wipe the melamine surfaces of the form with denatured alcohol. After the alcohol dries, vacuum the surface with the bristle attachment.
Step 3: Affix inlays or decorative aggregate to the bottom of the form with spray adhesive. These jadeite pebbles will accent the surface of the backsplash ridge.
Step 4: Install reinforcement. This No. 4 rebar is hung from the sides of the form with wire ties. The steel wire mesh rests on the rebar. The blocking underneath the rebar is temporary.
Step 5: Thoroughly mix the dry ingredients. This includes the concrete mix, fiber reinforcement, pigments and waterreducing admixture. The Cheng Concrete Exchange kit used here included everything (except the concrete in premeasured containers).
Step 6: Add water and thoroughly mix the concrete; then shovel it into the form. Avoid disturbing the rebar cage. Work the concrete into the form, using your hands to press it into corners.
Step 7: Repeatedly rap the form with a rubber mallet to vibrate the concrete so it settles and to remove air bubbles that will cause voids. Vibrate repeatedly as you fill the form.
Step 8: Strike off the surface of the concrete with a screed. (A piece of angle iron is used here.) You’ll need to work around the wire ties as best you can.
Step 9: Snip the wires that support the rebar cage, and press the cut ends into the concrete. Do not vibrate the form after you’ve cut the wires -- it could cause the rebar cage to sink.
Step 10: Strike off the surface again, screeding over the form edges in a sawing motion. When the concrete is smooth and level, cover it with plastic sheeting and let it cure for four days.
Step 11: Remove the screws holding the form together and then carefully strip off the form boards. Do not pry against the fresh concrete; use other parts of the form for leverage instead.
Step 12: Grind the surface. I used an angle grinder and a sequence of 50-, 100-, 200- and 400-grit discs to wet-grind the countertop.
Step 13: For a smoother surface, apply a coat of colored slurry to the surface. The slurry should be mixed to the consistency of toothpaste and pressed into any voids with a putty knife.
Step 14: Clean up vertical surfaces with diamond pads. To achieve a high gloss, wetpolish the horizontal surface with an angle grinder and 800- and 1,500-grit discs.