Patio Door Security: Protecting Your Biggest Vulnerability

Patio doors are designed for light, views, and easy garden access. Unfortunately, these same qualities often make them your home’s most vulnerable entry point.

Understanding patio door weaknesses—and how to address them—protects your property without sacrificing the lifestyle benefits these doors provide. This complements our broader window security guide.

The Attraction for Criminals

Why Patio Doors Are Targeted

• Large glass panels: Visibility into your home to confirm whether burgling is worthwhile
• Rear location: Concealed from street view, allowing longer attack time
• Original hardware: Often fitted with minimal security as standard
• Known weaknesses: Common models have well-known vulnerabilities
• Force potential: Larger doors can sometimes be flexed or lifted off tracks

Common Attack Methods

Sliding doors:

• Lifting off the track (simplest method if anti-lift absent)
• Forcing the lock (single-point locks are weakest)
• Breaking glass and reaching the internal lock
• Using the gap between door and frame

French doors:

• Attacking the meeting point between doors
• Exploit single-point locks (only one engagement point)
• Force the rebate (overlap joint between doors)
• Targeting the weaker passive leaf

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Criminals don’t overcome strong security—they find weak security. Patio doors are often the weakest link in otherwise secure homes.

Sliding Patio Door Security

Essential Security Features

Anti-Lift Devices The most basic sliding door attack simply lifts the door up and out of its track. Anti-lift devices prevent this by:

• Blocking upward movement
• Securing the door within the frame
• Usually fit at the top of the door

Track Blockers/Bars A physical bar in the track prevents the door from sliding open even if the lock is defeated:

• Simple and highly effective
• Can be removed for legitimate use
• Various styles from basic bars to purpose-designed products

Multipoint Locks Single-point locks engage at one location. Multipoint locks engage at several points:

• Typically 3-5 locking points
• Much harder to force
• Standard on quality modern doors
• Can be retrofitted to some older doors

Security Cylinder If the lock uses a Euro cylinder:

• Anti-snap cylinders are essential - learn why in our article on lock snapping
• Ensure correct sizing (minimal protrusion)
• TS007 3-star for insurance compliance

Assessment Checklist

Walk to your sliding door and check:

• Can you lift the closed, locked door? (If yes, anti-lift needed)
• Is there only one locking point? (If yes, multipoint upgrade advisable)
• Is the cylinder high-security or standard?
• Is there a way to block the track from inside?
• How visible is the door from outside the property?

French Door Security

The Dual-Door Challenge

French doors have two panels meeting in the middle. This creates unique vulnerabilities:

• Primary leaf: The door you open normally
• Secondary (passive) leaf: Usually bolted top and bottom
• Meeting point: Where the two doors come together

Essential Security Features

Shoot Bolts Vertical bolts at top and bottom of each door that engage into the frame:

• Both doors should have functioning shoot bolts
• Must actually be used (not just present)
• Multi-engage systems lock multiple bolts with handle turn

Central Locking Point The main lock where doors meet:

• Should be multipoint (engaging at several heights)
• Mortice deadlock for wooden French doors
• High-security cylinder for modern systems

Hinge Security Hinge-side attacks are possible on French doors:

• Hinge bolts prevent removal if hinges are attacked
• Security hinges with non-removable pins
• Particularly important on outward-opening doors

Flush Bolts vs Surface Bolts

• Flush bolts: Installed within the door edge, neater appearance
• Surface bolts: Mounted on door face, can be stronger

Glass Considerations

The Breaking Question

Many people assume glass is the primary vulnerability. In reality:

• Breaking glass makes noise (deterrent for many burglars)
• Large glass panels are expensive to break cleanly
• Lock attacks are often quieter and faster
• Glass attack still requires reaching internal locks

Glass Security Options

Laminated glass:

• Plastic interlayer holds glass together when broken
• Entry requires sustained attack, not single strike
• Significantly increases attack time
• Recommended for patio doors

Toughened glass:

• Stronger than standard glass
• Shatters into small pieces when broken
• Less effective than laminated for sustained attack resistance

Security film:

• Retrofit product applied to existing glass
• Holds shattered glass in frame
• More affordable than glass replacement
• Various grades available

Insurance Considerations

Many policies require specific glass types for patio doors. Check:

• Whether laminated or toughened glass is specified
• Minimum glass thickness requirements
• Whether security film is an acceptable alternative

This is especially important when preparing your home for holiday.

Additional Security Measures

Physical Barriers

Patio door bars:

• Metal bars fitting across the door
• Prevent sliding or penetration
• Highly effective deterrent
• Can be aesthetically intrusive

Concertina gates:

• Fold away when not needed
• Strong barrier when extended
• Common in commercial settings, available for residential

Electronic Security

Door contacts:

• Alarm sensors that trigger when door opens
• Should be on any home alarm system
• Also available as standalone units

Glass break detectors:

• Audio sensors detecting glass breaking
• Supplement alarm systems
• May have false positive issues with other sounds

Cameras:

• View of patio door area
• Deterrent effect plus evidence collection
• Motion-activated lighting combines well

Visibility Management

Burglars survey before committing. Reduce their intelligence gathering:

• Net curtains or privacy film preventing internal view
• Don’t leave valuables visible from outside
• Motion-activated lighting for evening visibility

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The goal isn’t to make your patio door impenetrable—it’s to make it harder than the next potential target.

Upgrading Older Patio Doors

When to Retrofit

Retrofitting security is appropriate when:

• The door itself is structurally sound
• Budget doesn’t allow full replacement
• Property restrictions prevent major changes
• The door has years of life remaining

When to Replace

Replacement is better when:

• The door has other issues (drafts, water ingress, worn components)
• No viable multipoint lock option exists
• Glass is single-pane (energy as well as security upgrade)
• You’re renovating anyway

Retrofit Priority Order

1. Anti-lift devices (if sliding door)
2. Track blocker (if sliding door)
3. Multipoint lock or additional locking points
4. High-security cylinder
5. Shoot bolts on both leaves (French doors)
6. Laminated glass or security film

Take Action

Walk to your patio doors now and honestly assess their security:

1. Test the anti-lift: Try lifting the locked door
2. Count locking points: One is vulnerable; multiple is better
3. Check the cylinder: Standard or high-security?
4. Consider concealment: How much can criminals see from outside?
5. Identify quick wins: What can you improve this week?

Patio doors don’t have to be your weak point. With appropriate attention, they can be as secure as any other entry point.