How Secure is Your Door?

This free tool was built by 1st Defence Locksmiths Leeds to help homeowners understand how secure their door really is.

We are a professional locksmith company based in Leeds with over 15 years of experience in residential and commercial lock installations, lock repairs, burglary repairs and emergency callouts.

Over that time, we’ve attended hundreds of burglary-related lock and door repairs across Leeds and the surrounding areas. This has given us a very clear understanding of the most common real world security weaknesses found in UK homes.

Let’s be honest, most people don’t actually know whether their front door would stop a determined intruder. You lock it, maybe add a chain, and assume you’re door is secure.

This 60 second checker highlights the most common weak points in UK domestic doors and gives you an instant, easy-to-understand result. No sign-up, no email required.

What Makes a Door Vulnerable?

When professional locksmiths talk about break-ins, we aren’t talking about the movies. No one is standing on your porch with a set of tension wrenches picking your locks in the dark. Real burglary is usually fast and destructive. It all comes down to three main weak points.

The Door Frame

You can buy the most expensive lock on the market, but if it’s housed in a flimsy frame, a solid kick will split a wooden door and frame or knock out a uPVC door panel. The lock is only as strong as the door and frame.

The Lock Cylinder

If you have a standard uPVC or composite door, it likely uses a euro cylinder. A basic, budget cylinder can be snapped and extracted in under a minute using basic DIY tools. Lock snapping is one of the most common entry methods we see across Leeds, yet thousands of homes are still vulnerable to it. Find out in more in our in-depth guide on what is lock snapping?

The Glazing

A beautiful, fully glazed door or a large glass panel right next to the handle looks fantastic, but it's a massive security risk. Smashing the glass to reach in and turn a thumb-turn or grab a set of keys from the side is very common.

Wooden door vs uPVC door vs composite door

Here we explain the the good and bad points of the three main door types. Wooden, uPVC and composite doors. What are their strengths and weaknesses. 

Wooden Door 

1. Good Points: Incredibly solid and easy to structurally reinforce.

2. Bad Points: Susceptible to swelling and warping. Not insurance approved if not fitted with BS3621 lock.

3. How to Secure: Fit a BS3621 British Standard mortice lock and reinforce the frame.

Upvc Door 

1. Good Points: Low maintenance and great for keeping the heat in.

2. Bad Points: The plastic itself is flexible, and standard cylinders are incredibly easy to snap.

3. How to Secure: Upgrade to a 3-star anti-snap lock and add sash jammers.

Composite Door 

1. Good Points: Super strong core, excellent thermal efficiency, and highly secure if fitted correctly.

2. Bad Points: Still entirely reliant on the quality of the cylinder lock installed.

3. How to Secure: Ensure it is fitted with a TS007 3-star rated cylinder.

Why Lock Quality Matters 

If you take only one thing away from this page, let it be this: Check your lock ratings.

• Standard Euro Cylinders: Found on uPVC and composite doors. They have zero security rating and offer no resistance against lock snapping.

• 3-Star Anti-Snap Cylinders (TS007): These are the gold standard. If a burglar tries to snap them, the breaks in such a way that it prevents access to the multi point lock mechanism, keeping the intruder out. Upgrading to a 3-star lock is the single quickest, most cost-effective security upgrade you can make. We have a helpful guide to the best anti snap lock.

• BS3621 Mortice Deadlocks: For wooden doors, look for the British Standard "Kitemark" stamped on the faceplate. If it doesn't have the kitmark it won’t be BS3621.

How to Add Additional Security

Once your main locks are sorted, you can add physical layers of protection that make burglars skip your house entirely.

• Sash Jammers: Small, inexpensive metal arms fastened to uPVC frames. Even if an intruder compromises the lock, sash jammers physically stop the door from swinging open.

• London Bars & Birmingham Bars: Metal reinforcement strips fitted to the inside of wooden door frames. They absorb the force of a kick attack, stopping the timber from splitting.

• High-Security Handles: Reinforced handles make it much more difficult to attack the lock cylinder. High security handles are much stronger than standard handles and usually come with a cylinder guard protecting against drilling.

•  Smart Deterrents: Ring doorbells, CCTV, and visible security lights are brilliant deterrents. Burglars are opportunists looking for the easiest target on the street. However, electronics only change the probability of a burglary. They won't physically stop a break in. Pair your tech with solid physical security.

What Does Your Security Score Mean?

Once you finish the 60 second calculator, you’ll get a score between 15 and 100. Here is how to interpret it:

Score 80+ | Excellent Protection

Your door has genuine resistance. You’ve likely got British Standard or 3-star anti-snap locks, a sturdy frame, and minimal glass vulnerabilities. No door is 100% impenetrable, but yours will make it difficult for a burglar.

Score 60–79 | Moderately Secure

You’ve got a decent baseline, but there are clear gaps. You might have a great lock but a weak frame, or a solid door with basic, easily snappable cylinders.

Score Below 60 | High Vulnerability

Your door has critical weak spots that are easy to exploit. Most likely a standard uPVC lock without anti-snap protection or a wooden door without BS3621 locks and additional security devices. Don't panic it doesn't mean you'll be targeted imminently, but it does mean you should prioritise a few simple upgrades.

Want a Security Survey in Leeds?

This calculator is a fantastic, rapid health check, but it doesn’t replace a professional assessment.

If your score was lower than you’d like, or you just want absolute peace of mind from a local company in the Leeds area you can trust, get in touch with 1st Defence Locksmiths Leeds. We can chat through your results over the phone or book a straightforward, no-pressure home security assessment.

• No sales pitches.

• No unnecessary upgrades.

• Just honest, local expertise to keep your home secure.

Take the 60 second assessment above to find out where you stand!

Disclaimer:
This calculator is for general informational purposes only and is based on common residential door security standards and known entry methods. It does not replace a professional on-site security assessment. No system can guarantee complete protection against forced entry or burglary. For tailored advice, please consult a professional locksmith.