Door will not latch or lock: causes and fixes

Look before you replace anything

People often buy a new lock when the lock is fine. The latch bolt and the deadbolt have to meet holes in the strike plates on the frame. If the door has dropped or the frame has shifted, the bolt hits metal instead of the hole.

Close the door slowly and watch where the latch touches the strike. Scratches on the strike plate above or below the hole tell you which way the door is off.

Common causes

• Loose hinge screws: the door sags on the latch side. The top of the door rubs the frame and the latch sits low.
• Seasonal swelling: wood doors and frames swell in humid weeks and shrink in dry ones.
• Settling: the house shifts slightly and the frame goes out of square.
• Weatherstripping too thick: new seals push the door away from the strike.
• Worn latch: a spring that is weak or a bolt that sticks.

Fixes from simplest to bigger

1. Tighten every hinge screw. If one spins, replace it with a longer screw that reaches the framing behind the jamb.
2. If the door still sags, a longer screw in the top hinge pulls the door up and over.
3. Adjust the strike: file the opening a little or move the plate to line up with the bolt.
4. Plane or sand the door edge where it rubs, then seal the bare wood.
5. Replace a latch or a deadbolt that sticks even when the door is open.

Most of these are small adjustments. A door that keeps going out of line after adjustment may point to movement in the framing or the foundation, which is worth watching.

Deadbolts that will not throw

Test the deadbolt with the door open. If it turns easily open but not closed, it is alignment. Lift or push the door while turning the key; if it suddenly works, the strike needs adjustment.

If it is stiff even open, the lock needs lubrication with a dry lock lubricant or replacement. See lock and doorknob replacement.

Sliding doors and screen doors

Sliding glass doors that will not lock usually have worn rollers, so the panel sits low and the latch misses. New rollers often fix the latch too; see sliding glass door repair. Screen doors that do not latch often need closer or latch adjustment; see screen door repair.

Security for now

If an exterior door will not lock at night, a door wedge or a bar under the knob holds it until a repair. Text photos of the door edge, the strike and the lock, and we will bring the right parts.

Interior doors

Bedroom and bathroom doors that drift open or will not stay closed usually need the strike moved or the latch tab bent slightly. A door that swings by itself may be out of plumb; a hinge adjustment fixes it. See door repair.

Valley weather and doors

Most of the year the air here is dry, and doors fit well. During wet winter weeks, wood doors and frames swell and start to rub. When the Santa Ana winds blow hot and dry, they shrink again and latches can miss on the other side.

A door that only misbehaves in certain weeks is reacting to moisture. Sealing all six sides of a wood door, including the top and bottom edges, slows that swelling.

Tools you may have

A screwdriver, a longer wood screw, a small file and a pencil fix many latch problems. Rub pencil on the latch, close the door, and the mark on the strike shows exactly where it hits.

Doors in older homes

Older homes often have solid wood doors with many coats of paint on the edges and in the hinges. Paint buildup alone can keep a door from closing. Stripping the edge and resetting the hinges brings it back.

When the frame is the problem

If the gap between door and frame is uneven along the whole height, or the frame is visibly bowed, the jamb may need resetting. That is a bigger repair but still handyman work in most cases.

Double doors

French doors and double entry doors latch to each other, with flush bolts holding the inactive leaf at top and bottom. If the inactive leaf is not bolted, the active door has nothing firm to latch against. Check that both flush bolts drop fully into their holes.

Ball catches and closet doors

Closet doors often use ball catches or roller catches at the top. They need an occasional adjustment.

What to send

A photo of the door edge with the latch, a photo of the strike plate on the frame, and a short video of the door closing let us see the problem before the visit and bring the right parts.

Photo checklist