How to Fix a Sagging Door

Step 1: Diagnose the sag
Open the door and watch where it binds or drags. Check the gap around all four sides of the door. A wide gap at the top latch corner and a tight fit at the bottom latch corner is the classic sag pattern. Use a level on the hinge side of the frame to see how far out of plumb it has shifted.

Step 2: Inspect and tighten the hinges
Using a screwdriver, check every screw on every hinge. If any turn freely without tightening, the hole is stripped. Remove those screws, pack the holes with wooden toothpicks dipped in wood glue, let the glue dry fully (usually a few hours), then re-drive the original screws. In many cases this simple step restores a solid bite.

Step 3: Replace short screws with longer ones
Standard hinge screws are often only three-quarters of an inch long and only grip the door casing, not the structural stud behind it. Swap at least two screws per hinge - ideally the top hinge screws - for three-inch screws that anchor into the framing. This makes a noticeable difference on most entry doors.

Step 4: Check and adjust the hinge mortises
If a hinge leaf sits proud of the surface (not flush), it can throw the door out of alignment. Use a chisel to carefully deepen the mortise so the hinge sits flat. Conversely, if the mortise is too deep, add a thin cardboard shim behind the hinge leaf to bring it flush.

Step 5: Plane or sand a sticking edge
If the door still rubs after hinge work, mark the contact point with a pencil or use a piece of carbon paper. Remove the door from its hinges and use a hand plane or belt sander to remove material only from the marked area. Work in small passes - it is easy to take off too much. Rehang and test before removing more material.

Step 6: Realign the strike plate
A sagging door often causes the latch bolt to miss the strike plate. Try moving the strike plate down and toward the stop molding in small increments to match where the latch actually lands. Use a chisel to extend the mortise if needed, then reattach the plate with fresh screws.

Step 7: Test and finish
Hang the door, open and close it several times, and check the gap on all sides. The door should swing freely, latch without force, and show a roughly even gap around the perimeter. Touch up any bare wood with matching paint or stain to protect against moisture.

• Always wedge the door open or have a helper hold it before removing hinge pins - doors are heavier than they look
• Wear safety glasses when chiseling or planing wood
• Keep fingers clear of the hinge side when swinging a heavy door back into place
• Use the right length screw - screws that are too long can break through the interior trim or split framing
• If you smell mustiness or see soft, discolored wood around the frame, stop and assess for rot before proceeding
• Do not plane the latch side of a fire-rated door without confirming the repair won't compromise its rating