Difficulty rating: Medium
These tasks may be tricky so will suit you if you're experienced in DIY, or simply love a challenge.
Before you get started on any of our 'how to' guides, please take a moment to read through our DIY safety tips.
1. Choosing a lock: look for the Kitemark
The best and strongest locks have a kite mark and are passed to British Standard BS3621. Most insurance companies insist you have these. They're also recommended by crime prevention officers.

2. Best locks for external doors
- The more levers, pins or discs a lock has, the more difficult it is to pick.
- The main locks on your exterior doors should be to BS3621 standard. Most insurance companies demand this level of security.
Front door
- When possible fit two locks on your front door - both to BS3621 standard. Position a mortice deadlock about halfway up the door.

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- And fit a night latch on your front door one-third of the way down. To install this lock, see Section 4 below.

- If you only fit one lock, go for an automatically dead-locking night latch made to BS3621 standard.

Back door
- Protect your back door with a mortice sash lock to BS3621 (fig. 4)

Additional security - bolts
- It's a good idea to fit hinge bolts, especially to doors that open outwards as the hinge knuckle pins are a weak point. Position them 150mm below the top hinge and 150mm above the bottom hinge.

- Strengthen your back door with security mortice bolts.

- Follow the manufacturer's instructions to install these bolts.
Helpful hint...
When drilling for the mortice recess, use a piece of tape on your drill bit to mark how deep you should drill each time.
4: Fitting a night latch
- Read the manufacturer's instructions before starting this job.
- Mark and drill the hole for the cylinder through the door stile about one-third of the way down from the top of the door.

- The diameter and position for the hole will be in the manufacturer's instructions, usually shown as a template.
- Place the slip ring B over the cylinder C and insert it into the hole in the door. Then place the fixing plate D over the hole. Secure it with connecting screws A, so the cylinder and fixing plate are upright .

- If you haven't already done it, take the key out of the cylinder.
- Check the arrows on the thimble E and lock cover plate F line up.

- Place the case I over the fixing plate, making sure connecting bar G enters the slot in thimble E. The connecting bar often needs shortening – you can do this with a hacksaw.
- You might need to mark and cut the edge of the door if the lock cover plate F has a lip. Use a chisel for this.
- Replace the case and fix screws H to attach the case to the door.
- Line up the striking plate (the metal piece on your door frame that the lock bolt enters) with the lock bolt J. Mark its position on the door frame and chisel out the wood for a flush fit. Fix it in place with the screws provided.

Helpful hint...
Make sure all your door frames are in good condition or they'll make your locks ineffective. If the frame can be moved or rocked when you push it, either add extra wall fixings, or replace or repair the frame.


5: Replacing a Euro cylinder lock
Some locks are so good they'll stop intruders in their tracks. For example, PVCU composite doors are fitted with Euro cylinder locks. Put one on your door and you'll immediately upgrade the security of your home.
Look for the latest security standard - BSEN1303:2005 - that tests against all methods of beating a lock. The cylinder also has Secured by Design accreditation - a police-preferred specification that focuses on crime prevention.
6: Replacing a rim cylinder lock
Replacing a rim cylinder on an external timber door is an easy and effective way to secure your home without having to change the entire lock or door.
Upgrade to a British standard rim cylinder and you can be confident the lock been tested to withstand all known ways to break it.
7: Replacing a handle
If your door handle is stiff or it's tarnished and dated, you may need a replacement.
Yale's PVCU replacement handle is easy to fit, and has a multi-point lock system for maximum security. To start off you'll need to find out the size of your lock.
Video Link: https://www.youtube.com/watch?v=SCbXGJcU7hc