Window Framing, Piece by Piece: Header, Kings, Jacks, Sill, Cripples
The Problem
You can't follow a framing plan, a how-to video, or an inspector's comment if the vocabulary is soup. Window openings have more named parts than any other stretch of wall, and every one of them exists for a load-path reason — knowing which stick is which is the difference between framing an opening and copying a picture of one.
The Main Parts and What They Do
Walking one framed opening (2x6 pre-cut studs, in this example):
- Header — the beam across the top of the opening (a double 2x10 here). It picks up the load from above that the missing studs would have carried.
- King studs — full-height studs on each side of the header, running from bottom plate to top plate. They flank the opening and tie the header assembly into the wall.
- Jack studs (trimmers) — shorter studs inside the kings, running from the bottom plate up to the header. These are the header's legs: they carry its load straight down to the plate.
- Sill — a doubled horizontal plate at the bottom of the opening, framing the base the window sits on.
- Cripples — the short studs below the sill, kept on the wall's regular 16-inch-on-center layout so sheathing and drywall land on schedule.
- Rough opening — the width and height left in the middle when all of the above is in place: the hole the window unit actually fits into.
Left and right sides mirror each other — king outside, jack inside, on both sides of every opening.
Pro tip: The load path is the memory trick: weight from above lands on the header, the header hands it to the jacks, the jacks post it down to the bottom plate. Everything else — kings, sill, cripples — is there to keep the wall continuous and give the window and the finishes something to fasten to.