To build floating shelves, cut a hollowed door, and install it over a wooden cleat. You need a hollowed door, a 2-inch-by-4-inch board, lag screws, wood glue and brad nails.
- Trace the installation location on the wall
Use a stud finder, pencil and 4-foot level to trace a horizontal line that matches the length of the hollow door you're using. Mark the spots where the studs are along the line.
- Cut the door
Attach a 40-tooth carbide blade to a circular saw. Cut the door to your desired width.
- Cut the cleat
Measure the length and width of the hollowed area of the door. Cut a cleat out of a piece of 2-inch-by-4-inch wood that matches the dimensions.
- Drill holes into the studs
Drill holes that are 1/4 inch in diameter into each marked stud.
- Drills holes into the cleat
Attach a 1/8-inch bit to the drill, and hold the cleat straight along the drawn line. Drill holes through the cleat and into each pre-drilled hole.
- Install lag screws into each hole
Use a ratchet to install a lag screw into each hole.
- Chisel away the corrugated cardboard cores
Use a chisel to file down each corrugated cardboard core at least 1 1/2 inches deep.
- Test the shelf
Place the shelf over the cleat on the wall to ensure that it fits. Make adjustments accordingly.
- Glue the shelf to the cleat
Apply wood glue along the top of the cleat and the inner bottom of the shelf, and install the shelf on the cleat.
- Install nails at the back
Install nails at the back of the shelf that go through the shelf and into the cleat. Space the nails 8 inches apart.