Door That Won't Latch? Read the Gap Before You Touch the Strike

A door that won't latch has one of three faults: the latch bolt meets the jamb above or below the strike opening, the bolt lines up but the door cannot travel far enough for it to drop in, or the bolt itself is not springing out. The first is the most common, and the repair starts with how the door hangs, not with the strike. Check the hinge screws and let the door settle where it is going to stay before you alter the strike plate, because a strike adjusted to a door that is still drifting will be wrong again.

Read the gap, then read the contact mark

Close the door as far as it will go and look at the gap between the door and the frame on all three sides. On a door that hangs true, the gap runs roughly even along the top and down the latch side. When the latch corner has dropped, the gap along the top is usually wider toward the latch side than over the hinges, and the bolt now meets the jamb below the strike opening. When the gap is tighter toward the bottom of the latch side and open at the top, the bolt may be meeting it above. The gap suggests a direction; the contact mark confirms it.

To get a mark, work with the bolt extended, because turning the knob or lever pulls the bolt in and leaves nothing to touch the strike. Rub a little chalk on the angled face of the bolt and leave the handle alone. Ease the door shut slowly until the bolt just touches the strike, then open it and see where the chalk landed on the metal strike plate. Wipe the chalk off with a dry cloth. Chalk is dry, so it should not stain, but keep it off painted or stained wood and try it somewhere out of sight first if the strike is finished. Skip lipstick, wax and anything greasy near a finished surface.

If the gap is even and the bolt still will not catch, skip the next two sections. The problem is in depth or in the bolt, further down.

The bolt lands off the opening: start with the hinges

Open the door and check every screw in the hinges, both leaves. Loose screws in the jamb leaf let the door shift, and that alone can move the bolt off the opening. Tighten them firmly. A screw that spins in a stripped hole needs a fresh grip: glue a few wooden toothpicks or a thin hardwood plug into the hole, let it set, trim it, and drive the screw again.

If the door still sits out of line, which hinge to work on and what to do there depends on the hinge, the jamb and the condition of the frame. Look at which hinge has pulled away or has play in it, and at whether the jamb has shifted or the wood around the screws has split. Some people replace a short jamb-leaf screw with a longer one that reaches the framing behind the jamb; that suits some installations and not others, and the screw has to fit the hinge's countersink so the leaves still close fully. Do not overdrive it, which can bow the jamb. A split jamb, a shifted frame or a hinge worn loose in the knuckles needs a proper repair, and a carpenter is the right call if the frame itself has moved.

Hinges with play in the knuckles or a pin that rocks will keep letting the door move however tight the screws are. Replace them with hinges of the same size, corner radius and thickness so they sit in the existing mortises, or choose a set made for that door. Our door hinges are a place to compare sizes and finishes.

Filing or moving the strike: only within the lock's limits

Once the door hangs where it is going to stay, close it again and see what is left of the miss. A small miss on ordinary interior hardware can sometimes be handled by enlarging the strike opening slightly, but only within what the lock manufacturer allows. The bolt must still engage the strike securely, with enough of it left to hold the door shut, and the instructions that came with the set outrank any rule of thumb. If you no longer have them, look the set up by its manufacturer and model before touching the strike.

Exterior doors, fire-rated doors and other specialized assemblies are different. Their strikes are part of a rated or security arrangement, so check the manufacturer's guidance for the door and the lock before filing or moving anything. Deadlatching locks add a second consideration. A deadlatching lock has a small auxiliary plunger next to the bolt, and that plunger must rest on the face of the strike rather than drop into the opening. Enlarge or shift the opening so the plunger can enter it and the lock no longer deadlatches, which defeats the purpose.

A larger miss means moving the strike. Unscrew it, deepen or extend its recess in the jamb with a sharp chisel so the plate sits flush in its new position, plug the old screw holes so the new ones do not wander into them, and redrill pilot holes before you fit the screws. A new hole that overlaps an old one pulls the screw sideways, and the strike creeps back toward where it started.

Some strikes have a small adjustable tab inside the opening. If the door latches but rattles, the maker's instructions will say whether the tab can be bent to take up play, and by how much. Adjust a little at a time, because a strike set too tight causes the next problem on this list.

The bolt lines up, but the door will not close far enough

If the gap is even and the bolt sits square with the opening, yet the door bounces back or only catches when you lean on it, something is stopping the door before the bolt can drop in. On an interior door, the usual suspects are a door stop molding set too tight against the door face, layers of paint on the stop and the door edge, or a door that has swollen in humid weather. A door that latches in winter and fights you in summer may be swelling. Once it has dried out, check whether the top and bottom edges are sealed, since bare wood takes on moisture, before reaching for a plane.

Exterior doors add the weatherstrip. A seal that pushes the door back just as the bolt needs to travel the last fraction of an inch can be the wrong profile for the gap, installed in the wrong position, or compressed more than its maker intends. Do not move the strike to make room for it. Check that the seal suits the gap it is sealing, that it is mounted the way its instructions show, and that it compresses by the amount specified. A new seal can also feel firm for a while before it relaxes.

The opposite problem shows up on old doors and frames that have spread: the gap on the latch side is so wide that the bolt barely reaches the strike, catches on its lip, and lets go when the door is pulled. Packing the strike with card or cardboard is not a repair for an excessive gap, because it compresses and crumbles. Correct the fit instead, by re-hanging or shimming the hinge side properly, repairing the jamb, or using a repair the lock or door manufacturer approves, and bring in a carpenter if the frame has moved.

The bolt itself will not come out

Open the door and work the knob or lever while you watch the edge. If the bolt is slow to spring out, stops short, or stays in when you let go, the latch is binding, not the door. Several things can cause that. Paint on the faceplate and door edge can glue the bolt in its housing; clean it off carefully. Mounting screws tightened too hard can pinch the case, so loosen them slightly and test. Trim or a spindle that is out of line, or a set put together incorrectly, can drag on the mechanism too. A slow bolt does not prove the spring is worn: work through these first.

If the set has been taken off and refitted recently, check that the latch went back the right way round. The bolt's angled face must face the direction the door closes, toward the stop. A latch installed backward meets the strike with its flat face, and the door will never latch.

Lubrication helps a sticky latch only if it suits the mechanism, so follow what the maker of your set recommends rather than reaching for whatever oil is in the drawer. If the bolt is clean, installed correctly and still lazy, the latch itself may need replacing.

Replacing the latch or the set

Not every set includes a latch. Dummy sets and trim-only products, which are meant to look like a handle without operating a latch, do not, and a replacement latch must match the lock series, the backset and the preparation in the door, not simply the manufacturer. Check the backset, the bore and edge hole sizes and the faceplate before you order. Where a whole new set is the answer, our interior door sets and entry door sets are listed by function, and the locks and latches collection covers other latching hardware. Confirm that a set fits the door's thickness and existing holes before you buy.

The tradeoff with replacing is that new hardware fixes only the hardware. If the gap was uneven when you started, a new latch meets the same misaligned strike, and the door still will not catch. Fix the hang first, then judge the latch.