Doors that do not latch, and why alignment is usually the cause

A latch looks simple, but it asks a lot of a door. The angled tongue has to meet the strike plate at exactly the right height and depth, slide past the lip of the plate, and drop into the hole in the frame. A deadbolt asks even more, because a round bolt must line up with a hole that is only slightly bigger than the bolt itself.

That means the whole door has to hang in the right place. The hinges set its position at one side, the frame sets it at the other, and the lock lives in the gap between them. If the door sags a little, if the frame shifts, or if the strike drifts, the bolt and the hole no longer meet. The lock itself may be perfectly healthy.

So the first job is not to open the lock. The first job is to notice how the door sits in its frame. Look at the gaps around the edge. They should be even on the top and the latch side. If one corner is tight and the other is wide, you already know something has moved. Close the door slowly and watch the gap on the latch side from top to bottom. A gap that narrows toward the top is the classic picture of a sagging door, while a gap that is wide at the top points to a frame that has twisted or a hinge that has been bent.

The strike plate keeps a record of what the door has been doing. Look at the metal plate and the wood around it. Shiny scratches or a bright scuff mark on the edge of the hole show where the latch has been dragging. A dent below the hole means the door is hanging low, and a scrape above means it is high.

You can make this even clearer with a pencil trick. Rub a little pencil lead or chalk on the tip of the latch bolt, close the door and turn the knob. The mark will transfer to the strike where the tongue touches. If the mark falls beside the opening and not inside it, you can see how far the door and the strike are out of line.

Take a moment to also check whether the strike is loose, and whether the screws are the short ones that came with the plate, which often grab only the thin trim of the frame and not the solid wood behind it. Screws that have worked their way out of soft wood let the plate move, and every time the door slams the plate shifts a little further. Tightening the screws, or replacing them with longer ones, is a simple fix that sometimes cures the problem outright. Our notes on strike plates and door frames explain the hardware in more detail.

Most latching problems begin at the hinges. A door is heavy, and years of use pull the screws in the top hinge loose from the frame. When that happens, the top corner of the door moves away from the latch side and the whole door drops. The bolt now meets the frame lower than the hole.

Open the door and look at the top hinge. Are the screws tight, or do they turn freely? Is the hinge leaf pulling out of the wood? Check the middle and bottom hinges too. A stripped screw hole is common, and the cure is to fill the hole with glue and wooden dowel pieces or to use a longer screw that reaches the framing behind the jamb.

Be careful with heavy doors. If you remove screws from a hinge, the weight of the door can shift suddenly. Work with one hinge at a time and have a helper or a wedge under the door. If you are not comfortable with this, a locksmith or a door carpenter can finish the job without damage.

• Tighten every hinge screw by hand with a screwdriver.
• Replace stripped screws with longer ones that reach the frame.
• Fill stripped holes with glue and a thin wood dowel when needed.
• Check that the hinge leaves sit flat in their recesses.
• Work on one hinge at a time with the door supported.

Wood moves. In humid weather it swells, and in dry weather it shrinks. In the North State the swings can be large, with dry hot summers in the valley and cold, damp winters in the mountain towns. A door that closed perfectly in August can bind in January, or the other way round.

If a door only fails to latch in certain seasons, swelling is a likely cause. Look for shiny, worn spots along the edge that rub against the frame. That is where the door is touching. Sanding or planing a small amount can restore the gap, but only after you check that the hinges are tight, because a sagging door will also rub in the same spot.

Weather is not the only trigger. A new rug, a heavy storm door or a new coat of paint can all change how a door sits, so think about what changed recently. Painted edges matter, too. A thick coat of paint adds thickness and can make a bolt rub. Paint on the strike or in the bolt hole can also stop the latch from moving all the way. If the door is a painted exterior door, make sure the top and bottom edges are sealed, since bare wood soaks up moisture and swells.

Sometimes the lock really is the problem. A latch that sticks inside the door, a spring that has weakened, or a knob mechanism that does not retract the bolt fully can all cause trouble. To test this, take the door out of the equation. With the door open, turn the knob or lever and watch the latch. It should snap back smoothly and spring out again with some force.

Do the same with the deadbolt. Turn the key or thumb turn and watch the bolt move. It should slide in and out without grinding. If it hesitates with the door open, the lock needs cleaning, lubrication or replacement. If it moves freely when the door is open and only binds when the door is closed, you are looking at alignment.

Sometimes the trouble is hiding in the lever or knob itself. A loose handle that droops on its spindle may not pull the latch back all the way, and a handle that feels sloppy is a sign of wear inside. A latch bolt that seems to move normally but fails to catch may have a worn tip. Over time the beveled edge can wear down and lose its ability to ride over the strike. A replacement latch is a small, inexpensive part, and our team can fit one at your door as part of a lock repair visit.

Deadbolts are less forgiving than latches. The bolt is a solid bar that must slide straight into a hole in the frame. If the hole is too far left, right, up or down, the bolt will rub the edge of the strike plate or the wood. You may feel the key bind halfway through the turn, or you may have to lift or push the door to get the bolt to move.

This is a classic sign of misalignment. Many people force the key, and that is how keys bend and cylinders wear. If you have to lift the door to lock it, stop and look at the door. A turned key that has to fight is a key that is being asked to do something the lock was not made for.

In cold regions, a deadbolt can seem to stick only in winter because the door shifts a little with temperature. The guide on a deadbolt that sticks only in the cold covers that pattern. Some of the same ideas apply here, because the cause often traces back to the door and not to the lock.

Start with the simplest steps. Tighten the hinge screws, tighten the strike screws, and clean the latch and bolt with a dry cloth. If the screws spin, use longer ones. If the strike plate is slightly off, you can sometimes file the opening a little larger so the bolt enters easily. File only a small amount at a time, and stop when the latch moves freely.

If the door has dropped a little and the hinge screws are tight, shimming a hinge can lift the door. A thin piece of cardboard behind the bottom hinge leaf pushes the door toward the latch side, while one behind the top hinge pushes the other way. This is a classic carpenter's trick and it works because small changes at the hinge become larger changes at the latch.

Avoid using force. If you hammer the strike or pry at the frame, you risk splitting wood that is hard to repair. Also avoid drilling bigger holes in the frame if you are unsure, because a deadbolt hole that is too large weakens the door's security. When in doubt, take photos of the gaps, the strike and the hinges and ask for advice. Pictures taken in daylight, with the door closed and then open, tell a locksmith a great deal before anyone arrives, and they help you describe the problem accurately in the request form.

Call a locksmith when the cause is not clear after the basic checks, when the strike or frame is cracked, when the lock mechanism seems damaged, or when the door is a security concern such as an entrance that will not stay locked. A door that cannot latch is a door that cannot protect your home, and that is worth fixing as soon as you can arrange it.

A locksmith can adjust the strike, reposition a bolt hole, fit a new latch, install a longer strike with screws that reach the framing, or replace the lock entirely if needed. We carry common hardware in our service van and can often finish the work at your door. For bigger frame damage, a carpenter may be needed, and we can tell you if the job goes beyond what a lock can fix.

If your door will not stay locked tonight, a stopgap such as a secondary lock or a barrier on the inside can hold it until the repair. For urgent situations see our 24 hour emergency locksmith page, and for routine problems use the request form to describe what you see.

Offices, shops and community buildings have doors that must latch on their own, closing behind each person who passes. These doors use closers, hydraulic arms mounted at the top, which pull the door shut and control its speed. If a closer is set too weak, the door will not reach the frame; if it is set too strong, the latch may slam and bounce back.

Closers have adjustment screws for the sweep and for the latch speed, the last few inches before the door closes. A small turn can fix a door that stops just short of latching. Over time, closers also leak fluid and lose force, so a door that once closed with ease may stop. Replacement is the right answer in that case. Look for oily streaks on the body of the closer or on the wall behind it, which show that fluid has escaped. A closer that has lost its fluid will swing freely and slam, and no adjustment screw can bring the force back.

Business owners should treat a door that does not latch as a security and safety concern. Our pages on commercial door hardware and commercial locksmith work describe how closers, panic hardware and strikes are set up. For a wider view of storefront needs, panic hardware basics for stores is a useful companion.

Once the door latches again, a few habits will keep it that way. Do not slam it, since a hard slam rattles screws loose and jolts the strike, and do not let it hang open on its hinges for long periods with a heavy load. Do not hang heavy items such as a wet coat or a bag from the door, as the weight pulls on the hinges. If children swing on the door, gently discourage it.

Check the screws twice a year, ideally when the seasons change. A short look at the gaps and a turn of each hinge screw takes five minutes and prevents most sagging. If you use a lubricant, choose one made for locks and hinges and use it lightly, because the wrong product attracts dirt. Our guide on lock lubricants explains what to use.

Finally, if you are doing a bigger inspection of your home, include every door. The home security walkthrough lists what to check, and if the door that will not latch is one of several, that list helps you set priorities. A few small fixes done early save you from a hard lock problem later.