Occasionally, upper cabinets are installed over an island or other freestanding set of lower cabinets with no wall to anchor them. While slightly more tricky than installation on a wall, upper cabinets can be mounted to the ceiling securely. When ordering the cabinets, specify that all four sides of the cabinets must be finished. Unlike wall installation, cabinets hanging down from the ceiling will have all four sides visible. You won't want the back of your cabinets to be finished with particle board. If your cabinets don't come correctly finished, order decorative panels to fit on the back and sides as needed.
Things You'll Need
Cabinet support stand
3-inch deck screws with washers
Spread construction adhesive on the back and sides of the cabinet, if finishing is required. Set the side and back panels in place. Let the adhesive dry.
Measure the cabinets and determine exactly where they will be installed on the ceiling. Draw an outline of the cabinet footprint on the ceiling.
Drill through the plaster and into the attic space at the four corners of the drawing and in a few spots along the perimeter. This will identify the space from the attic area.
Go into the attic. Nail 2-by-4 boards between the ceiling framing boards around the cabinet's perimeter. Drive screws through the 2-by-4s at an angle to attach the lumber to the ceiling framing. This lumber will reinforce the ceiling so it will be able to support the cabinet's weight.
Position the cabinet so it is lined up with the 2-by-4s in the attic space. Hold the cabinet in place with a cabinet support stand. You can also ask a friend to assist you.
Open the cabinet doors. Drive 3-inch deck screws through the top of the cabinet and into the ceiling. Drive a screw with a washer every 4 to 6 inches all the way around the cabinet's interior perimeter.
Remove the cabinet support stand.
Examine the inside of your cabinet before installation. If the top of the cabinet does not seem sturdy enough to withstand the cabinet's full weight, reinforce the top with 2-by-4 lumber. Before you put on the decorative panels, drive screws through the side and back of the cabinet into the lumber. Use the 2-by-4s as mounting rails to hang the cabinet from the ceiling.