Surry Hills Locksmith

When people think about home security, they usually think about the front door. Yet in many inner Sydney homes, the weakest point is at the back: a glass sliding door onto a courtyard, a set of bi-folds added in a renovation, a pair of old French doors or a ground-floor window facing a lane.

This guide explains how these doors and windows are usually secured, why many of them are weaker than they look and what practical, affordable improvements make the biggest difference. It applies to terraces, cottages, townhouses and apartments across Surry Hills, Darlinghurst, Redfern, Paddington, Woolloomooloo and Moore Park. For service details, see our security locksmith page.

Why the back of the house matters

In the terrace streets of the inner east, front doors sit in full view of the street. Rear doors and windows usually do not. They face small courtyards, lanes or neighbouring roofs, where someone can work without being seen. Renovations often add large areas of glass at the back, chosen for light and views rather than security.

That is why a secure front door and a weak back slider is such a common combination, and why the back of the house deserves equal attention.

Glass sliding doors

How most sliders lock

Most aluminium sliding doors lock with a small hook latch inside the handle. When you push the lever, a hook swings out and catches a keeper on the frame. It keeps the door closed against wind, but it is not designed to resist force.

Common weaknesses

Lifting. Many sliders can be lifted slightly in their track. If the door lifts far enough, the hook can disengage or the door can be lifted out entirely.
Levering. A weak hook can be pried open by forcing the door at the latch.
Worn rollers. Worn rollers let the door sag, so the hook no longer catches the keeper properly.
Missing keepers. Some keepers crack or loosen over time and are never replaced.

Improvements that work

Fit a keyed sliding door lock. A keyed lock replaces or supplements the hook latch with one that must be unlocked with a key.
Add anti-lift blocks. Small blocks fixed in the top track stop the door being lifted out.
Add a secondary bolt. A bolt at the bottom or top of the door that locks into the frame gives a second point of security.
Service the rollers. Replacing worn rollers and adjusting the door makes the existing lock work as it should.
Consider a security screen door. A properly installed security screen adds a strong outer layer and lets you leave the glass open for air.

See our door lock installation service for keyed slider locks and secondary bolts.

Bi-fold doors

Bi-folds are popular in renovations because they open a whole wall to the courtyard. They also have more moving parts and more places to secure.

The main leaf usually has a handle lock. Check that it is keyed and that it throws into the frame or floor.
The other leaves should have bolts at the top and bottom that lock into the frame or track. If they only have small flush bolts that can be slid open, consider lockable alternatives.
Hinges should not be removable from outside.
Tracks should be kept clean so the bolts can engage fully.

Ask the door supplier or a locksmith to check the system after installation. Many bi-folds are fitted with basic hardware that can be upgraded.

French doors

Many terraces in Paddington, Surry Hills and Darlinghurst have timber French doors opening onto balconies or courtyards.

The fixed leaf is often held only by small bolts at the top and bottom. If those bolts are weak or loose, the whole pair can be pushed open.
The opening leaf often has an old mortice lock. Check that it deadlocks.
The meeting stiles, where the two doors meet, should be tight. A gap lets someone insert a tool.

Improvements include stronger flush bolts on the fixed leaf, a modern mortice deadlock on the opening leaf and, where the doors are original, careful repair rather than replacement. Our guide to heritage doors on terraces explains how to keep period doors working.

Windows

Which windows to secure

Not every window needs a lock. Focus on:

Ground-floor windows facing a courtyard, lane or side passage.
Windows reachable from a fence, a roof, a balcony or bins.
Bathroom and laundry windows that are often left open.

Window locks by type

Sash windows in terraces can be fitted with sash stops or keyed sash locks that let the window open a little for ventilation but no further.
Sliding windows can take keyed sliding window locks similar to slider locks.
Awning and casement windows can take keyed winder or stay locks.
Louvres are hard to secure; a security screen behind them is often the best option.

Window restrictors and child safety

In NSW, strata buildings have rules about window safety devices for windows above ground level, aimed at preventing children falling. Restrictors limit how far a window opens. They also add a degree of security. Check with your strata manager about the rules for your building.

Keep an escape route

Security should never trap you inside. Make sure every bedroom has a way out in an emergency, keep keys for window locks near the window, out of reach from outside, and make sure everyone in the house knows where they are.

Apartments

In apartments, sliders and windows are usually less exposed, but there are exceptions:

Ground-floor and podium apartments with courtyards face the same risks as houses.
Balconies near trees, awnings or neighbouring roofs can be reached.
Common area windows are the owners corporation's responsibility, not yours.

If you rent, ask your agent before fitting locks or bolts. If you own, check your by-laws before changing anything visible from outside. See our guide to apartment security in Surry Hills.

Renting and lock changes

Tenants in NSW usually need the landlord's consent before adding or changing locks, and the landlord should receive a key to any new keyed lock. Many landlords welcome improvements to sliders and windows, especially if the tenant covers the cost. Put your request in writing. See our guide to landlord and tenant lock change rules in NSW.

Typical jobs, step by step

A renovated terrace with a lifting slider

A Redfern owner notices the back slider lifts slightly when pushed. We replace the worn rollers, fit anti-lift blocks and a keyed sliding door lock, and key the lock alike with the back door.

Bi-folds with weak bolts

A Paddington family's bi-folds have small flush bolts that can be slid open from inside once the glass is breached. We fit lockable bolts top and bottom and check that the main leaf lock throws fully.

Sash windows facing a lane

A Surry Hills renter wants to leave their sash windows open a little at night. With the landlord's consent, we fit sash stops that allow ventilation but stop the window being opened further from outside.

Signs your doors and windows need attention

The slider lifts or rattles when locked.
The hook latch does not catch every time.
Bi-fold bolts do not reach their holes.
French doors move when pushed, even when locked.
Window locks are missing, broken or the keys are lost.
Rollers grind or the door is hard to slide.

Any of these is worth fixing. Most repairs are quick and inexpensive. See lock repair.

Maintenance that keeps locks working

Even the best lock fails if the door around it is neglected. A few minutes every few months keeps sliders, bi-folds and windows locking properly.

Vacuum the tracks. Grit and leaves in a slider or bi-fold track wear the rollers and stop bolts from engaging fully.
Wipe and lubricate. Use a silicone spray on tracks and a dry lock lubricant in keyed cylinders. Avoid heavy oil, which collects dust.
Check screws. Loose screws in keepers, hinges and lock bodies are common on doors that are opened many times a day.
Test every lock. Lock and unlock each door and window, and make sure the keys are where everyone expects them to be.
Watch for movement. Timber doors swell in wet weather; if a lock becomes stiff after rain, the strike may need adjusting rather than the lock replacing.

Problems caught early are usually small repairs. Left alone, they become locks that will not engage, keys that snap or doors that cannot be locked at all.

Questions we are often asked

Is a keyed slider lock really better than the built-in latch?

Yes. The built-in hook latch is designed mainly to keep the door closed. A keyed lock must be unlocked with a key and is much harder to force.

Will anti-lift blocks stop the door opening?

No. They sit in the top track and stop the door being lifted out. The door slides normally.

Can you fit locks to aluminium windows?

Usually, yes. There are keyed locks for most aluminium sliding and awning windows.

What does it cost to secure the back of a house?

It depends on the number of doors and windows and the hardware chosen. Many homes can be made far more secure for a modest cost. We quote before starting. See our guide to locksmith costs in Surry Hills and Sydney.

The bottom line

In many inner Sydney homes, the weakest points are glass sliders, bi-folds, French doors and windows at the back. Keyed locks, anti-lift blocks, secondary bolts, window locks and good maintenance make a big difference for a modest cost. Keep an escape route, get consent if you rent and fix problems early.

For sliding door and window security, call Surry Hills Locksmith Service on 02 3820 5414, open 7 days, 7:00am to 12:00am, or request a quote.

Sliding Door and Window Security for Inner Sydney Homes