Repair a window lock.

Repairing a window lock is usually a cost-effective alternative to replacing the entire unit. Whether you have modern uPVC, traditional timber, or sleek aluminium frames, keeping the locking hardware in top condition ensures your home remains energy-efficient and secure.

What Does the Work Involve?

• Initial Inspection: The locksmith assesses whether the issue lies with the handle, the internal gearbox, or the "espagnolette" (the long metal strip that runs down the side of the window).
• Alignment Check: Often, a lock "fails" because the window sash has dropped or shifted, meaning the locking bolts no longer line up with the keeps in the frame.
• Component Removal: The locksmith removes the handle and unscrews the internal mechanism to inspect for snapped springs or stripped gears.
• Cleaning and Lubrication: In cases of stiff operation, a professional deep-clean and the application of lithium-based grease can often restore function without needing new parts.
• Part Replacement: If the mechanism is broken, a like-for-like replacement is installed. For older windows where parts are obsolete, a "universal" gearbox or rail may be retrofitted.
• Testing and Adjustment: The locksmith ensures the window seals tightly against the frame to prevent draughts while allowing the handle to turn without force.

Typical Costs

The cost of window lock repairs depends largely on the type of window and whether the mechanism is still in production. Emergency call-outs after hours will naturally command a premium.

Prices include VAT. Costs may increase if the locksmith has to "bypass" a lock that is jammed shut, as this requires specialist tools and more time to avoid damaging the frame.

How Long Does It Take?

• Basic Handle Replacement: 20–30 minutes per window.
• Adjusting a Dropped Sash: 30–45 minutes to realign the hinges and keeps.
• Full Mechanism Replacement: 1–2 hours, depending on the age and condition of the frame.
• Obsolete Parts: 2–3 days if a specific mechanism needs to be ordered from a specialist supplier.

DIY or Professional?

Replacing a simple window handle is a straightforward DIY task that requires only a screwdriver. However, if the window is jammed shut or the internal gearbox has shattered, a professional locksmith is essential.

Expert Tip: Attempting to force a jammed window open can snap the uPVC profile or crack the glass, turning a £120 repair into a £500 window replacement.

Locksmiths carry "over-riding" tools that can retract the bolts from the inside without damaging the frame. Furthermore, a professional repair ensures your windows meet the security standards required by your insurer.

Choosing the Right Tradesperson

• Check Qualifications: Look for a locksmith who is a member of the Master Locksmiths Association (MLA).
• Vetting: Ensure they have a clear DBS (Disclosure and Barring Service) check for your peace of mind.
• Warranty: A reputable pro should offer at least a 12-month guarantee on both parts and labour.
• Questions to Ask:
  • Do you carry common uPVC gearboxes on your van for a first-time fix?
  • Is there a "no fix, no fee" policy if the window is beyond repair?
  • Will the new locks meet my insurance provider's minimum security requirements?

UK Regulations

• Fire Safety (Part B): Repairs must not hinder the use of windows designated as fire escapes (egress windows).
• Security (Part Q): For newer homes, replacement hardware should ideally meet PAS 24 standards to maintain the building’s security integrity.
• Insurance Compliance: Most UK insurers require "key-operated locks" on all ground-floor and accessible windows to validate theft cover.

Common Problems

• The "Spinning" Handle: This usually means the internal spindle has rounded off or the gearbox has shattered internally.
• Window Won't Close Fully: Often caused by debris in the track or a "dropped" sash that is hitting the frame keeps.
• Stiff Operation: Usually a sign of lack of lubrication or the mechanism being forced out of alignment over time.
• Key Won't Turn: Common in coastal areas where salt air can corrode the small pins inside the lock cylinder.

Frequently Asked Questions