Simple Panel Bed (All Mattress Sizes)

Lay out the two headboard legs and strike a pencil line down each, 2-1/4" in from the outside edge — every panel board's end registers to it.

Dry-fit all the panel boards first. Then glue and fasten the TOP 1x8 to the legs, and work downward, running a bead of glue along each board-to-board edge as you go. That seam glue is the panel's real strength.

Glue the headboard's whole top edge, set the 1x3 cap with even overhangs at the ends and flush at the back, and fasten — brads if you have the nailer (they vanish under filler), screws if you don't.

Same construction at ankle height: one panel board across the short legs, capped with the other 1x3.

Glue each 2x4 cleat and lay a 1x8 side rail on top of it; fasten from the outside — nails preferred, again for the hiding. The cleat is the structure; the 1x8 is the face.

Screw the side rails to the legs with the 3" screws. The plan's sanity-saver: cut a spacer block from 2x4 scrap to hold the rail at its height while you drive — solo assembly goes from juggling to routine.

Measure the actual width between the cleats at the headboard (about 57" on a queen, but measure yours), cut the 2x4 to fit, and screw it to the headboard. It's the fourth side of the slat-support rectangle.

Screw the two 12-1/2" legs to the 78-1/2" center support with 3" screws — a T-section beam that carries the middle of every slat.

Center the spine down the bed and screw it to the headboard frame rail and footboard with 3" screws. Its top must land level with the side cleats — the slats sit on all three.

Lay the eighteen 2x4 slats across cleats and spine, about 4" apart, and screw down with 3" screws. 2x4 slats at 4" spacing is deliberate overkill — this platform will never bow, squeak, or care what mattress you put on it.

Fill the brad holes, sand, finish, and slide the mattress in.