Replace a door lock.

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