Sliding Door and Window Locks for South Australian Homes

The stock latch on a sliding or patio door is not a lock, it is a catch, and it is the single most common weak point our network sees in South Australian homes. The fix is a dedicated key-locked sliding door lock plus an anti-lift block on the track, both of which a locksmith can usually fit in one visit for well under the cost of a break-in claim.

Why sliding doors are the entry point burglars try first

Most Adelaide homes built from the 1970s through to the 2000s have at least one sliding door onto a patio, deck or side yard, and in a large share of the jobs our network attends after a break-in, that door is where entry happened. There are 2 reasons it is such an easy target. First, the factory latch on most aluminium and timber sliders only stops the door from rolling open, it does nothing to stop the door being lifted a few centimetres off its bottom track and swung out of the frame, a technique that takes seconds and no tools beyond a flat bar. Second, sliding doors sit at the back or side of the house, out of street view, which is exactly the privacy a burglar wants.

Window locks run a close second. Older aluminium-framed windows in particular often have a simple wind-out handle with no separate locking mechanism, so once the flyscreen is off, the window opens from outside in seconds.

Key-locked sliding door locks: what actually gets fitted

The upgrade that matters most is replacing (or supplementing) the factory latch with a lock that takes a key from the outside and cannot be flicked open by reaching through a broken pane or a gap in the frame. A vetted locksmith will typically choose from a few standard options depending on your door type and frame material:

• Surface-mounted sliding door lock: screws onto the face of the door and frame, key-operated, suits most aluminium and timber sliders without modifying the existing latch.
• Keyed hook lock or claw lock: hooks into the frame rather than just latching, so the door cannot be forced open even if someone gets a pry bar into the gap.
• Track-mounted secondary lock: a second, independent lock fitted lower on the track, useful if you want the door lockable at night while cracked open for ventilation.

Whichever is fitted, the point is the same, the door should not be able to be opened by anyone standing outside without a key, full stop. A door that relies purely on the roller latch is not secured, it is only closed.

Anti-lift blocks: stopping the door being lifted off the track

Anti-lift is the measure most homeowners have never heard of and most burglars rely on. Because sliding doors hang on rollers that sit inside a track, a door with a worn track or a small amount of play can be lifted a few millimetres and popped clear of the bottom rail, bypassing the latch entirely without breaking anything or making noise. An anti-lift block or pin, fitted into the top track, physically limits how far the door can be raised, which closes that gap. It is a small parts cost and a quick fit, and on older sliders our network attends, it is very often missing altogether. If your sliding door pre-dates 2010, assume there is no anti-lift measure until someone has checked.

Costs vary with door size, frame material and how many doors and windows you are doing at once, so treat these as a typical Adelaide range rather than a fixed price, your quote may differ. Bundling several doors and windows into one visit usually brings the per-item cost down because the callout is shared across the job.

Window locks: the second most common weak point

After sliding doors, wind-out and sliding windows are the next thing worth checking, especially anything at ground level or accessible from a low roof, pergola or wheelie bin. A key-locked window lock stops the sash or casement being opened from outside even if the flyscreen comes off, and on louvre windows it is worth checking each individual blade is either fixed or has its own retaining clip, because louvres can otherwise be lifted out one at a time. Bathroom and laundry windows get missed constantly because they feel low-risk, but a window round the back of the house is exactly the spot a burglar has time to work on unseen.

A quick check before you call anyone

You can rule out the worst gaps in 5 minutes without any tools. Slide the door or window open a few centimetres and try lifting it, if it moves upward more than a few millimetres before the rollers bind, there is no anti-lift measure in place. Check whether the latch is the only thing holding the door shut, if there is no separate keyhole or thumb-turn on the inside, it almost certainly is. Look at the track for wear, gaps or a bent rail, because a worn track makes lifting easier even with a lock fitted. If any of those raise a flag, it is worth getting a locksmith to look at the whole house rather than just the one door, since the same builder-grade hardware is usually on every slider and window in a home built in the same era.

For the front and back entry doors themselves, see securing your front door and our broader rundown of the best door locks for a home if you are upgrading more than just the sliders. A locksmith attending for door locks can usually quote the sliding door and window work in the same visit, which is worth raising when you book, see our residential locksmith page for what a full home security check covers.