I am looking to install some custom shelving for a 4’x4’ closet. I would like the shelves to be in an L shaped configuration against the rear and right walls of the closet. The back portion of the shelves will be 18” deep, and the right will be 12” deep. Every part of the shelf touching the walls will be supported by 1x2’s screwed into the studs. For the shelf itself, I’m using 3/4” birch plywood.
Because there is not a way to cut the shelves as a single piece without wasting material, I’m planning to cut each shelf into a 18”x3’ piece and a 12”x4’ piece. The 18”x3’ piece will only be supported from the walls on two sides, so I will need a crossmember. This is where I am unsure how to proceed.
I have 2 studs along the side walls opposite each other about 9” off of the rear wall. If I want the crossmember to be driven into these studs, I could use pocket screws to secure a 2x2 across the width of the closet. This means the front half of the 18” shelf will not be supported. If the 1x2 alone is strong enough, I could move the 2x2 crossmember all the way to the front.
Should I secure the crossmember with one or two pocket holes on each side? Should I use a 2x2 or a 2x4? Should the pocket holes be facing up or down? Should the crossmember span the middle of the shelf so it can go into the studs, or at the front? Are pocket screws the best solution here?