Why Won’t My Door Latch? Common Causes and Safe Fixes

A door that won’t latch is almost always a strike plate alignment problem caused by the door or the house frame shifting slightly over time, not a broken latch mechanism. This guide covers how to diagnose whether the latch, the strike plate, or the door itself is misaligned, the common causes (hinge sag, seasonal wood movement, settling), and the safe fixes ranging from a five-minute adjustment to a hinge repair.

Diagnosing With the Lipstick or Chalk Test

Rub a bit of lipstick, chalk, or dry-erase marker on the latch bolt’s face, then close the door as far as it will go without forcing it. Open the door and look at the mark left on the strike plate: if the mark sits above, below, or to the side of the strike plate’s opening, you’ve confirmed a straightforward alignment problem rather than a broken latch or lock mechanism. If the mark lands squarely in the opening but the door still won’t latch, the issue is more likely a worn or damaged latch bolt itself, or the door binding against the frame before it can fully close.

Why Doors Drift Out of Alignment

Hinges are the most common culprit: screws back out slightly over years of use, or the top hinge’s screws strip in the wood, letting the door sag on that corner and drop out of alignment with the strike plate. Seasonal humidity swings also swell and shrink the door slab and jamb, which is why a door can latch fine in summer and refuse to catch in winter, or vice versa. In older homes, gradual foundation settling can shift the entire frame out of square over years, which shows up as a latch problem along with a door that no longer sits flush at top or bottom.

Fixing Minor Misalignment: The Strike Plate Adjustment

For a small offset (an eighth of an inch or less), file the strike plate opening slightly larger with a metal file in the direction the mark indicates, rather than moving the whole plate. For a bigger offset, remove the strike plate, extend the mortise with a chisel in the needed direction, and reinstall, patching the exposed gap with wood filler if it will show. This single fix resolves the large majority of “door won’t latch” complaints and takes about 15 minutes with basic hand tools.

Fixing a Sagging Door via the Hinges

If the door also drags or hits the frame as it closes, rather than only failing to latch, the hinges are the more likely root cause. Tighten any loose hinge screws first; if a screw hole is stripped, remove the screw, fill the hole with wood glue and toothpicks or a hinge-repair plug, let it dry, and re-drive the screw so it has fresh material to bite into. For a door sagging noticeably at the latch side, driving one longer 3-inch screw through the top hinge into the framing stud (replacing a short screw that only reaches the jamb) often pulls the door back into alignment without removing the door at all.

When It’s the Frame, Not the Door

If the strike plate has already been adjusted multiple times and the problem keeps recurring, or the door frame itself looks visibly out of square, the jamb may have racked from structural settling. That’s a bigger repair involving re-squaring or reinstalling the frame, and it’s worth having a carpenter or door installer assess it rather than continuing to chase the symptom with strike plate adjustments.

Frequently Asked Questions

Why does my door latch in summer but not in winter?

Wood expands with humidity and contracts in dry, cold air, so a door and jamb that fit closely in summer’s humidity can shrink just enough in winter to change the latch alignment. Slightly enlarging the strike plate opening in the direction of the shift usually resolves it for both seasons.

Can I just move the whole strike plate instead of filing it?

Yes, for offsets larger than about an eighth of an inch, relocating the strike plate (and patching the old mortise and screw holes) gives a cleaner result than filing an oversized, oddly-shaped opening.

Is a door that won’t latch a security problem?

Yes, a door that doesn’t fully latch can often be pushed open even with a deadbolt engaged if the latch itself isn’t seated, and it’s an easy fix, so it’s worth addressing on any exterior door promptly rather than leaving it.