Why does my door swing open or closed on its own?

Why a door drifts

A door that swings by itself is nearly always hanging on a tilted hinge line. Gravity then pulls the door's weight toward the low side, so it drifts closed if the hinge side leans one way and open if it leans the other. The question is why the line is no longer upright.

There are several common reasons. Poor alignment can occur because your house has settled or shifted over time, the door frame is old or warped, or the door is sagging on its hinges.^[1] Another is a frame that was never quite true, which can make a door look warped or exaggerate a small warp.

Test before you touch anything

Set the door about halfway open and let go. Note which way it moves and how fast. A slow drift points to a small lean; a door that slams shut or flies open has a bigger one.

Then hold a level against the hinge-side jamb, top to bottom. If the bubble sits well off centre, the frame leans, and the door is only following it. If the jamb is upright, the hinges are the likely culprit: open the door and lift its free edge. Any movement means worn or loose hinges cause your door to sag.^[1]

Fix loose hinges first

Worn or loose hinges cause your door to sag.^[1] Tighten every screw in each hinge, top hinge first, on both the door and the jamb side. A screw that spins without biting has a stripped hole. Pack it with wooden toothpicks dipped in wood glue, let it dry, trim flush and drive the screw again. Where the screws were ripped out of the door or jamb, use new screws that are longer and larger in diameter.^[2] A longer screw in the top hinge that reaches the framing behind the jamb pulls the whole door back up.

Shim the hinge if it still drifts

If tight hinges do not stop the drift, adjust the angle of the door with a shim. You can replace the hinges so that they fit more securely on the door frame. Or you can add shims under the hinges.^[1]

A shim is a thin strip of cardboard or plastic, cut to the size of the hinge leaf and slipped behind it. Shim the top hinge to move the top of the door, the bottom hinge to move the bottom. Add one layer at a time and retest by letting the door go from halfway. If the drift gets worse, take the shim out and try the other hinge. Stop when the door stays where you leave it. Cardboard cut from a cereal box is often enough.

When it only happens some of the year

Wood moves with the seasons. A door that drifts in July and behaves in January is more likely swelling than leaning. If your door closes and latches easily during some seasons but not others, this may be a sign that changes in temperature or moisture are causing your door to warp, even just temporarily.^[1] It is usually best to get through one dry and one damp season before making permanent changes such as cutting the frame.

A warped lightweight interior door can sometimes be shimmed, but it is rarely worth much effort; see whether to repair or replace an interior door.

Stop and call a pro if

• The jamb is far out of plumb or the door gaps are uneven all round. A frame that has moved may reflect settling, which sanding and shims do not fix.
• The jamb is cracked, soft or rotted. Screws will not hold in rotten wood.
• You see cracks in the wall or trim above the door. That can point to movement in the house; see why cracks form above doors and windows.
• The fix means removing trim, cutting the frame or rehanging the door. If the job grows past a small repair, remember that Virginia requires a contractor's licence when the work is valued at $1,000 or more.^[3]

Getting help in Virginia

If a stubborn door turns into a bigger job, read how to fix a door that sticks and how much it costs to fix an interior door in Virginia. More home repair answers are on the Home Repair answers page, and you can browse local pros in Doors and Windows pros on Loclis.

When you are ready, describe the door once and licensed local pros quote it.