How to Make a Shelf Using 2X2's

Find three wall studs in the wall using a stud finder and mark a line across them at the height you want the shelf to go. Use a level when marking the line to ensure it is straight.

Place a 48-inch-long plank of 2-by-2 lumber on the level line and use two 3-inch drywall screws to attach it to the wall at each stud point. There will be three stud points, as studs are spaced 16 inches apart, and six screws altogether. This is the wall cleat for the shelf.

Position two planks of 6-inch-long 2-by-2 lumber at right angles to the shelf cleat, one at either end. Secure them with three drywall screws.

Place a sheet of 10-by-48 inch plywood (3/4-inch thick) over the shelf cleat and use 1-inch wood screws driven through the back of the plywood into the cleat to secure it.

Miter the ends of two pieces of 11-inch 2-by-2 lumber to opposing 45 degree angles. Slot them between the end of the 6-inch planks that are perpendicular to the cleat and the edge of the plywood shelf top. These are support brackets

Secure them with finishing nails through the end into the 6-inch plank and through the top of the plywood into the end of the brackets.