To make a floating shelf, mark the location on the wall, cut the door blank and cleats, mount the cleats on the wall, and attach the shelf onto the cleats with nails. You need a tape measure, a hammer, a saw, a stud finder, a level and glue.
- Mark the location of the shelf, and cut a door blank
Find the horizontal location of the shelf with a level, use a pencil to mark the stud locations, and mark a straight line on the wall with a string. Fasten the straight edge guide to the door with a clamp, and cut the door blank lengthwise.
- Cut and mount the cleats on the wall
Measure the distance between the outer door veneers, and cut the 2- by 4-inch board into cleats that fit the measured distance. Drill holes at the stud locations, and attach the cleats to the wall with lag screws.
- Remove the cardboard core, and install the shelf
Cut about 1 inch of the corrugated cardboard cores off of the edge, and scrape off the glue, taking care not to scratch the wood. Glue the cleat top to the door blank, and fasten the shelf onto the wood cleat with nails.