How do I fix a door that won't latch?

A door that won't latch is usually out of line rather than broken. The latch tongue or the deadbolt is landing above, below or short of the hole in the strike plate on the frame. Schlage lists the usual reasons: your house has settled or shifted over time, the door frame is old or warped, or the door is sagging on its hinges.^[1] Work through the fixes in order, from the simplest, and test after each one.

Find out where the latch is missing

Close the door slowly and watch the latch meet the strike. Does it hit the top or bottom edge of the opening, stop short of the frame, or click in only when you push? Then try the trick Schlage recommends: rub chalk or lipstick on the bolt before locking and unlocking it, then look for the smear on the strike where it rubs.^[1] The mark tells you which way the door has moved.

Two quick clues narrow it down. First, if you have to lift the door to lock it, the bolt or latch is probably hitting the bottom of the strike rather than extending fully into it.^[1] That points to sagging hinges. Second, a door that latches fine in some months and not others is reacting to the weather. Schlage says that can mean changes in temperature or moisture are causing your door to warp, even just temporarily, and advises that you make adjustments when the door is not fitting, rather than in the season when it closes easily.^[1]

Tighten the hinges first

Loose hinges are the most common cause and the easiest to fix. JELD-WEN's care guide recommends cleaning the hardware and tightening loose screws any time a door is not opening or closing properly, or at least twice a year.^[2] Tighten every screw in every hinge leaf, on both the door and the frame.

If a screw in the top hinge just spins, the short screw has stripped the soft jamb. On exterior doors, Therma-Tru's installation manual calls for long #10 screws through the hinge, into the stud, in the hole closest to the weatherstrip, to anchor the door frame and prevent sagging.^[3] A single long screw there often pulls the whole door back up so the latch lines up again. Schlage's other options for a sagging door are replacing worn hinges so they fit the frame securely, or adding shims under the hinges.^[1]

Adjust or move the strike

If the hinges are tight and the latch still misses, adjust the strike to where the latch actually lands:

• A small miss. File the inside edge of the strike opening on the side the chalk mark shows. This is often enough for a latch that catches a sliver of metal.
• A bigger miss. Unscrew the strike, move it up or down, fill the old screw holes with glued wood slivers or toothpicks, and chisel the mortise to fit.
• The door rattles or needs a push. The strike is set too far out or in. Therma-Tru's manual describes adjusting the strike plate in or out for proper weatherstrip contact and door operation.^[3]
• The bolt will not go all the way out. The pocket behind the strike is too shallow. Schlage says to chisel the bolt hole until it is 1 inch deep and lets the bolt extend fully without dragging.^[1] It also notes that the strike supplied with a new lock is the correct size and shape for its bolt,^[1] so use it rather than an old one left from a previous lock.

On exterior doors, check the seals as well. Schlage warns against weatherstripping that is so thick it obstructs the bolt or keeps it out of the bolt pocket.^[1] A door that has to be forced against a new, fat strip will not latch on its own, and it strains the hinges. How to weatherstrip a drafty door covers choosing a thinner profile.

When the door has swollen or the frame has moved

Wood moves with humidity. Simpson Door recommends approximately 3/16 inch of clearance for swelling when a door is hung in fully dry conditions,^[5] and Marvin notes that wood doors need a stabilization period after installation, sometimes up to a year, to adjust to humidity.^[6] A new door that binds in its first humid summer may settle on its own.

If the gap along the latch side is tight at the top and wide at the bottom, the frame may be out of square. Masonite puts it plainly: If the frame a door hangs in is not true and plumb, the door will appear to be warped.^[4] Planing the door edge is the last resort, not the first. If you do plane it, Masonite's instructions say the top, bottom and hardware edges must be sealed after fitting,^[4] or the bare wood keeps soaking up moisture.

When the latch itself is the problem

If the latch is slow to spring back even with the door open, the hardware needs attention. JELD-WEN recommends oiling the hinges with a light oil once a year or when they are noisy, and spraying graphite lubricant into the keyway.^[2] A worn interior passage latch is an inexpensive part, replaced with one of the same backset. For a deadbolt that drags, see why a front door is hard to lock.

In an older house, think before you chisel or sand a painted jamb. If your home was built before 1978, it may have lead-based paint.^[7] The EPA says the RRP Rule generally does not apply to homeowners working on their own home,^[7] but it recommends lead-safe practices, and it requires contractors working in pre-1978 homes to be lead-safe certified.^[7]

Stop and call a pro if

• The jamb, the threshold or the wall beside the door is soft, cracked or water-stained.
• New cracks have appeared in the drywall above the door, or several doors in the house stopped latching at the same time. That suggests the house is moving, which is a job for a structural contractor, not a latch fix.
• The door is a fire-rated door and the fix would mean cutting or planing it.
• The lock is electronic or wired, or the strike is an electric strike.
• The house was built before 1978 and the fix means sanding or chiselling painted wood that you would rather not handle.

You can browse handyman services, find handymen around Blacksburg, or read the other handyman answers, including whether to hire a handyman or a carpenter for doors and windows. If the door still won't latch, describe the door repair once and local businesses quote it.