Locks, alarms and the fabric that keeps you safe

This is the map for everything in this category: what the standards stamped on locks and alarms actually mean, how often each device wants testing, and the mechanical niggles that decide whether your house locks the way your insurer assumes it does. Each section hands off to a full guide when you want the method in detail.

Locks: the two standards that matter

BS3621 is the British Standard for key-operated mortice deadlocks on timber doors: the kitemarked five-lever lock insurance policies mean when they ask for a deadlock on final-exit doors. TS007 is the star-rated standard for the euro cylinders and handles on uPVC and composite doors; three stars in total is the level that defeats lock snapping, the favoured attack on older cylinders.

A lock only earns its rating if it works without a fight. A key that needs more of a wiggle every week is a lock announcing its retirement, and stiff locks and sticking doors are mostly ten-minute fixes if you catch them early. On uPVC doors the usual suspect is not the lock at all: when the handle will not lift without a shoulder against the frame, the multipoint mechanism is out of alignment and the door needs adjusting, not replacing.

Alarms: three devices, one rhythm

Smoke alarms, carbon monoxide alarms and intruder alarms age in different ways, but they share a maintenance rhythm: press the test button monthly, believe the low-battery chirp the first time, and replace units at their printed date. If a ceiling somewhere is beeping at you right now, the pattern of the sound tells you exactly what it wants.

A carbon monoxide alarm belongs in every room with a fuel-burning appliance, one to three metres from it at head height, and landlords in England must provide one wherever there is a fixed fuel-burning appliance other than a gas cooker. An intruder alarm that keeps crying wolf is failing at its one job: most false alarms trace back to a tired backup battery, an insect on a sensor or a draught, and all of those are fixable.

Cameras and video doorbells get the marketing budget, but they mostly record what the fabric failed to stop. Fit them after the locks and alarms are right, not instead.

Doors and windows that actually close

Most security failures are not dramatic. They are a door that has dropped on its hinges so the deadbolt grazes the keep, a swollen sash nobody forces shut any more, a window handle that spins without engaging. The fix is usually adjustment rather than replacement: tightened hinge screws, an eased strike plate, a quarter turn on a uPVC hinge.

Glazing counts as security fabric too. Misted double glazing means the sealed unit has failed, and the money-saving move is replacing the unit rather than the whole window. Meanwhile the most forgotten external door in Britain hangs on the front of the garage: a garage door that is heavy, stuck or screaming gets ignored in a way a front door never would, even when the garage connects straight into the house.

The annual walk-round

Once a year, walk the outside of the house with fresh eyes, then the inside, and test everything that is supposed to keep weather and strangers out. The weekend the clocks go back is a natural slot: the dark evenings arrive, and you are already resetting things.

Keys, and who has them

Every house accumulates key debt: the old cleaner, the builder from the extension, the neighbour from three owners ago. If you have just moved in, changing the cylinders is cheap certainty and belongs on the first-week checklist. For everyone else an annual audit works: list who holds a key, retrieve the strays, and retire the flowerpot, because burglars know about flowerpots. A wall-mounted key safe with a decent rating beats every hiding place ever invented.

Before any time away, the ten-minute empty-house routine covers the security half of leaving: alarm set, key holder briefed, post managed, and nothing on show that says nobody is home.

None of this is glamorous, which is why it works better as calendar admin than as willpower. Put the walk-round, the alarm tests and the service dates into the home maintenance calendar once, and security becomes another thing that quietly ticks over.