Every crooked door in America started with a sloppy frame. Knowing how to frame a door jamb correctly is the difference between a slab that swings shut on its own and one you have to nudge with your foot every morning. This guide walks you through the rough opening, the king and jack studs, header sizing, and the shimming that actually keeps the jamb plumb after drywall goes up.
You can frame a standard 30-inch interior door jamb in about 90 minutes once you have your materials staged. The job costs roughly $35 to $60 in lumber and fasteners for a non-load-bearing wall, plus another $90 to $180 if you also need the pre-hung door slab.
Tools and Materials You Will Need
Gather everything before you cut a single stud. Running back to the truck mid-cut is how mistakes happen.
- 2×4 kiln-dried SPF studs, straight (sight down each one)
- 16d framing nails or a pneumatic nailer with 3-1/4 inch nails
- Circular saw or miter saw
- 4-foot and 6-foot levels
- Speed square and 25-foot tape
- Cedar shims, at least one bundle
- Pre-hung door unit, sized to your rough opening
For a 30-inch pre-hung interior door, your rough opening should measure 32 inches wide by 82-1/2 inches tall. A 36-inch door needs 38 inches by 82-1/2 inches. Add 3/4 inch in width for thicker carpet or tile finishes.
Step 1: Lay Out the Rough Opening
Mark the centerline of the door on the bottom plate first. From that centerline, measure half the rough opening width in each direction and snap a chalk line up the wall location. Square corners with a 3-4-5 triangle if you are framing a new wall rather than retrofitting an existing one.
Double-check your opening height against the slab. A 6-foot 8-inch door needs 82-1/2 inches of rough opening to accommodate the jamb, the door, and a 3/4-inch gap at the bottom for finished flooring.
Step 2: Install the King Studs
King studs run full length from bottom plate to top plate. They flank the door opening and hold the entire assembly rigid. Cut two king studs to the wall height (typically 92-5/8 inches for 8-foot ceilings with double top plates) and nail them in place with three 16d nails through each plate.
Sight each king stud for crown and orient the crown toward the opening. Plumb both studs with a 6-foot level on two faces before you toenail them down. A king stud that leans 1/4 inch will telegraph through every shim adjustment later.
Step 3: Cut and Install the Jack Studs
Jack studs (also called trimmers) sit inside the king studs and carry the header. For a 6-foot 8-inch door with a 1-1/2 inch thick header, cut jack studs to 81 inches. That gives you 82-1/2 inches of rough opening height once the header is set on top.
Nail each jack stud to its king stud with 16d nails staggered every 16 inches. Check for plumb again. The inside faces of the jack studs are what you measure between to confirm rough opening width.
Step 4: Build and Set the Header
For non-load-bearing interior walls, a flat 2×4 laid on edge between the jack studs works fine. For load-bearing walls, build a header from two 2×6 or 2×8 boards sandwiched with a 1/2-inch plywood spacer so the assembly matches a 2×4 wall thickness. Glue and nail the sandwich with 10d nails in a zigzag pattern.
Set the header on top of the jack studs and nail down through the king studs into the header ends with three 16d nails per side. Add cripple studs above the header up to the top plate, spaced 16 inches on center to match the rest of the wall layout.
Step 5: Install the Pre-Hung Jamb
Slide the pre-hung door unit into the rough opening from the swing side. Center it side-to-side with roughly 1/4 inch of gap between the jamb and each jack stud. Place shims behind each hinge location and behind the strike plate.
Drive 8d finish nails or 2-1/2 inch trim screws through the jamb, through the shims, into the jack stud. Check the reveal (the gap between door and jamb) at the top, latch side, and hinge side. A consistent 1/8-inch reveal means the jamb is plumb and square. Trim shims flush with a utility knife once you are satisfied.
Common Mistakes to Avoid
Skipping shims at the strike plate causes the latch to pull the jamb out of alignment over time. Driving nails too close to the hinge mortise can split the jamb. And using warped studs anywhere in the assembly guarantees that no amount of shimming will save the door.
Measure the rough opening diagonally corner to corner once everything is nailed. The two diagonal measurements should match within 1/8 inch. If they do not, pull the worst nail and re-set before the drywall crew arrives.
Final Walk-Through
Open and close the door at least ten times before you call the framing done. Listen for rubbing at the top corner or the latch side. A properly framed jamb lets the door swing freely from any position and stay put when released halfway. That is the test that separates rookie framers from the ones homeowners call back.
Verify the strike plate aligns with the latch bolt by closing the door slowly and watching the bolt engage the strike. Misalignment of more than 1/16 inch will cause the door to either rattle or refuse to latch cleanly. Adjust by filing the strike plate slot or shimming the latch-side jack stud a hair tighter before drywall covers everything up. A few extra minutes here saves a future callback to chisel out the strike plate after paint.
