Door lock replacement

In the UK, lock replacement isn't just about fitting a new bolt; it is about meeting specific British Standards that insurers demand. A correctly installed, high-quality lock acts as a primary deterrent against common entry methods like lock snapping, drilling, and picking.

What Does the Work Involve?

• Site Assessment: Identifying the door material (uPVC, timber, or composite) and the existing lock type to ensure a compatible replacement.
• Removal: Carefully unscrewing and extracting the old cylinder, mortice box, or multipoint strip without damaging the door leaf or frame.
• Preparation: Cleaning the internal housing and, if upgrading to a different lock size, minor carpentry or routing to accommodate the new hardware.
• Installation: Fitting the new lock body, cylinder, and faceplates, ensuring all fixings are flush and secure.
• Alignment: Adjusting the strike plate or "keeps" on the door frame so the latch and bolts engage smoothly without needing to pull or push the door.
• Testing: Operating the lock multiple times with the door open and closed to check for "binding" or resistance.

Typical Costs

The total cost of lock replacement is usually a combination of a call-out fee, hourly labour, and the price of the hardware itself. Emergency out-of-hours visits will significantly increase the labour portion of the bill.

Prices are influenced by your location (London and the South East typically command higher rates) and the specific brand of hardware chosen. Upgrading to a "keyed alike" system, where one key fits all doors, will also add to the material costs.

How Long Does It Take?

• Euro Cylinder Replacement: 20–40 minutes. This is usually a straightforward "one screw" job if the size is standard.
• Mortice Lock (Timber Door): 45–90 minutes. May require minor chiselling if the new lock body differs slightly from the old one.
• Multipoint Lock Mechanism: 1–2 hours. These involve long metal strips and multiple locking points that require precise alignment.
• Fresh Fit (New Installation): 2–3 hours. Creating new holes and recesses in a door that previously had no lock.

DIY or Professional?

While changing a basic Euro cylinder is a common DIY task, it carries risks. If you measure the cylinder incorrectly and it protrudes more than 3mm from the handle, it becomes vulnerable to "lock snapping." For mortice locks and multipoint systems, professional installation is highly recommended. Incorrect DIY fitting can void your home insurance if a burglary occurs and the locks are found to be non-compliant with BS3621 standards.

Choosing the Right Tradesperson

• Check Qualifications: Look for members of the Master Locksmiths Association (MLA), which requires technicians to be vetted, inspected, and qualified.
• DBS Checked: Ensure the locksmith has a recent Basic DBS check for your peace of mind.
• Transparency: Avoid "nationwide" call centres that quote low but charge high; look for a local independent with a physical address.
• Ask: "Does this lock meet BS3621 standards for my insurance?"
• Ask: "Is there a warranty on both the part and your labour?"
• Ask: "How many keys are provided as standard with this lock?"

UK Regulations

There are no legal "licences" required to be a locksmith in the UK, which makes choosing a trade-accredited professional vital. However, specific standards apply to the hardware:

• BS3621: The British Standard for thief-resistant locks. Most insurers require this for ground-floor external timber doors.
• TS007 3-Star: The gold standard for cylinder locks. This can be achieved with a 3-star cylinder or a 1-star cylinder paired with 2-star security handles.
• Fire Safety: If you live in a flat or a HMO, your front door must be a fire door. Replacing locks on these requires fire-rated hardware to maintain the door's integrity.

Always check your home insurance policy wording. Many specify that locks must be "5-lever mortice deadlocks Kitemarked to BS3621" or equivalent.

Common Problems

• Lock Protrusion: A cylinder that sticks out too far is a major security flaw. It should be flush with the handle or backplate.
• Misalignment: If you have to lift the door handle forcefully to lock it, the door has dropped. Continuing to use it will eventually snap the internal mechanism.
• Cheap Clones: Unbranded locks from discount sites often lack the internal hardened steel pins required to resist drilling.
• Key Duplication Issues: High-security locks often come with a code card. Without this, you may find it impossible or very expensive to get spare keys cut.

Frequently Asked Questions

What is the difference between a 2-star and 3-star lock?

This refers to the TS007 star rating system. A 3-star cylinder provides the highest level of protection against snapping and drilling. A 1 or 2-star lock requires additional security furniture (like reinforced handles) to reach the same level of protection.

Does a locksmith have to break the door to change a lock?

In the vast majority of cases, no. If you have the keys, it is a non-destructive process. Even if you are locked out, a professional locksmith will use "non-destructive entry" techniques like picking or bumping before resorting to drilling the lock.

How can I tell if my lock is BS3621 compliant?

Look at the faceplate (the metal part visible on the edge of the door when open). It should have the British Standard Kitemark engraved on it along with the code "BS3621".

Should I change the locks when I move into a new house?

Yes, absolutely. You have no way of knowing how many spare keys were cut by previous owners, tenants, or tradespeople. It is the only way to ensure you have total control over access to your home.

Can I have one key that opens both my front and back doors?

Yes, this is called "Keyed Alike." A locksmith can order or build cylinders that use the same key profile, provided the locks are of the same brand and type. It is very convenient but means if you lose one key, you may want to change all the locks.