Frame a Door Opening in Four Steps: Header, Jacks, Kings, Cripples

The Problem

A door opening is five kinds of stick with exact jobs and exact numbers, and naming them wrong at the lumber yard is the least of it — cutting them wrong means a door that won't fit its own hole. The framing must land on a rough opening the door's jamb actually wants.

The Technique

The anatomy first: jack studs border the opening and carry the header; king studs run full plate-to-plate beside them, nailed to the jacks; the header spans the top; cripples run from header to top plate.

1. Build the header. Width math: a "2-6" (30") door frames to a 32" rough opening — door plus 2" — and the header is cut 3" longer than that, 35", to land on both 1-1/2" jacks. In a non-load-bearing wall this crew builds it as a 2x6 on edge fastened to a flat 2x4 at the bottom and another on top; the flat stock floats proud of the 2x6 so drywall has backing at the corner. (In a load-bearing wall, header sizing is a code item that grows with the span.)

2. Cut jacks and kings, and fasten them. Rough-opening height here is 82-1/2" for an 80" door. The jacks are cut at 81": they stand on the bottom plate, whose 1-1/2" brings the header's underside to 82-1/2". Nail each jack to its full-length king first, then set the header on the jacks and nail through the kings into the header ends.

3. Stand the assembly on layout. One placement rule beyond the marks: keep the opening at least 4" off a perpendicular wall, so the door's handle clears when it swings open.

4. Fill in the cripples. Measure from the header's top to the top plate — 8-1/2" here — cut, and install. This crew stacks them directly over the jacks so the load path above the opening runs straight down into them.