Security

Why Your Deadbolt Will Not Lock Properly

If you have to lift, push, or shoulder the door to turn the deadbolt, the lock is fine — the bolt and the hole it drops into no longer line up. That is an alignment problem, and forcing it only wears the lock faster.

How a deadbolt is supposed to work

When the door is closed, the deadbolt should throw fully into the strike hole in the jamb with no resistance and no lifting. If it binds, stops short, or only works when you hold the door a certain way, the bolt is hitting the edge of the strike instead of dropping cleanly through it.

The usual cause: a dropped or shifted door

Doors settle. Hinges loosen and the slab drops, so the bolt now lines up a few millimetres low. Seasonal swelling in an Ottawa summer shifts it too. The tell is simple: if you can lift the door by the handle and then the bolt throws freely, the door has sagged. That points to hinges — see the signs your hinges need replacing — and it is the same root cause behind a misaligned latch.

Other causes

• A strike plate that was never positioned right, so the hole is slightly off from the start.
• Paint or debris built up in the strike hole, stopping the bolt short.
• A frozen or stiff lock cylinder in deep cold — a winter issue on exterior doors.
• A worn lock mechanism, the least common cause despite being the first thing people blame.

The Ottawa winter factor

Our climate is hard on exterior deadbolts in two distinct ways. First, the freeze-thaw swing between a damp fall, a deep-cold January, and a wet spring makes wood doors swell and shrink, so a bolt that lined up perfectly in October can bind by February and free up again in May. Second, moisture that works into the lock cylinder can freeze, leaving the bolt stiff or seized on the coldest mornings — the same problem we cover for a frozen door lock. A dry, graphite or PTFE-based lubricant rather than oil keeps the mechanism moving in the cold, and keeping the strike hole clear of ice stops the bolt jamming. If the door binds only in the coldest weeks, the cause is usually swelling and ice, not a failing lock.

The fix

The right repair depends on how far off it is. A small misalignment can be corrected by filing the strike hole or repositioning the strike plate. A larger drop means bringing the door back square at the hinges first, then aligning the strike. We do not just enlarge the hole and call it done — a sloppy strike means a deadbolt that does not fully engage, which is a security weakness. This is straightforward lock repair, and where the bolt or cylinder itself is worn it can extend to a door that will not lock at all.

What you can check yourself first

Before you call anyone, a few quick checks tell you a lot. With the door open, throw the bolt by hand — if it slides smoothly, the lock body is fine and the problem is alignment. Close the door and look at where the bolt meets the strike; a shiny scrape or a witness mark on the strike plate shows exactly which way the bolt is hitting. Try lifting the door slightly by the handle as you turn the key: if it then locks, the slab has dropped and the hinges are the real culprit, the same root cause as a misaligned latch. Clear any paint or grit from the strike hole. These checks will not always fix it, but they tell you whether you are dealing with the lock, the strike, or a tired set of hinges.

Why forcing it makes things worse

When a bolt fights back, the instinct is to lean on the key and muscle it home. That is the one thing not to do. Turning a key hard against a bolt that is jammed against the edge of the strike puts the whole load on the small internal parts of the lock — the tailpiece, the cam, the cylinder — and that is how a perfectly good deadbolt actually does wear out or snap a key. You end up converting a free alignment fix into a lock replacement. The same goes for slamming or shouldering the door to get the bolt to drop: every time you do it you wear the strike, loosen the hinges a little more, and accelerate the very sag that caused the problem. A bolt that needs force is telling you something is out of line; the answer is to correct the alignment, not to push harder. Left alone, a misaligned deadbolt rarely improves on its own — doors settle in one direction, and the gap usually widens with each season.

Do not leave it

A deadbolt that only half-throws is barely locked, and that is exactly the weakness a forced entry exploits — our notes on securing a front door against break-ins explain why full bolt engagement matters. If your deadbolt is fighting you, we will align it properly, flat-rate, same day across Ottawa and the Valley.