Platform Bed with Side Storage and 1x12 Divider Shelf

Using 3" self-tapping wood screws, build the inner frame from the 2x4 pieces. Check for square by measuring diagonals corner to corner and adjusting until they match.

Add the remaining joists to the inner frame, attaching with 3" self-tapping wood screws.

Measure and cut the side trim to fit. Apply glue to the 2x4 frame and use 1-1/4" brad nails to attach the trim, leaving a 1-1/2" gap along the top edge.

Repeat the previous step for the end trim.

Attach the storage support piece to the top of the inner frame with 3" self-tapping wood screws. This completes the platform.

Cut the storage top and bottom pieces and attach at the corners with 1-1/4" brad nails and glue, or with 2" screws or 1-1/4" pocket hole screws.

Set the dividers inside the top and bottom panels, inset 3/4", and attach with 1-1/4" nails and glue using a square as a guide.

Cut two 9-1/4"-long blocks and use them inside the box as a spacing guide for the shelves. Attach the two outer shelves with glue and 1-1/4" brad nails. For the middle shelf, toenail from the front at an angle into the vertical dividers.

Mark the location of every divider and shelf on the inside lip of the box. Dry-fit the back boards to check the fit, then remove, apply glue to all edges, and reattach one board at a time, nailing through the outer sides into each back board's side and top edges.

It's easiest to finish the platform and storage piece separately before assembling, since the bed is large and difficult to move fully assembled. Use 2" self-tapping screws through the storage base into the frame, and into the storage support piece on the mattress side.

Install furniture feet or caster wheels per the manufacturer's instructions. If additional support is desired, add center legs cut from 2x4, spaced about a third of the way down, and attach with 3" self-tapping wood screws.

Cut the plywood platform base to fit, leaving a gap on the storage side, and screw down with 2" screws — drilling a few ventilation holes so the mattress can breathe. Cut the mattress slats and space them about 4" apart across the bed, screwing down with 2-1/2" screws.