A window that suddenly refuses to lock can be both frustrating and unsettling. For many homeowners, it raises immediate questions about security, safety and whether a costly replacement is on the horizon. The good news is that most window lock problems are far more common and far more fixable than people expect.
Across Dorset and the wider South Coast, we regularly help homeowners whose windows feel stiff, misaligned or simply will not lock as they should. In many cases, the issue has built up gradually rather than appearing overnight. Understanding why a window lock stops working is the first step towards resolving it calmly and correctly.
Window locks are mechanical components, and like all moving parts, they are subject to wear over time. Daily use, changes in temperature and natural building movement all play their part.
One of the most frequent causes we see is misalignment. When a window no longer sits squarely within its frame, the locking points struggle to engage properly. Even a few millimetres of movement can prevent the lock from catching, making the handle feel stiff or ineffective.
Another common issue is general wear and tear inside the locking mechanism itself. Over years of opening and closing, internal parts can become worn, dry or damaged. This is especially true in coastal areas where salty air can subtly accelerate corrosion.
In some cases, the problem lies not with the lock but with the window as a whole. Movement in the frame, settlement of the property or issues with the glass sealed units can all affect how the window operates.
Sometimes the locking mechanism has simply reached the end of its working life. Handles may turn loosely, seize completely or feel as though they are no longer connected to anything inside the frame.
In these cases, window repair is often straightforward. Modern double glazing repairs usually involve replacing the internal locking strip or gearbox rather than the entire window. This preserves the existing frame and glass while restoring full security.
It is worth noting that forcing a stiff handle can make matters worse. Applying pressure may damage surrounding components, turning a simple glazing repair into a more involved job.
Glass sealed units do more than provide insulation. They also contribute to the overall balance and alignment of the window.
If a sealed unit has failed, misted up or shifted slightly within the frame, it can place uneven pressure on hinges and locks. Over time, this imbalance can affect how the window closes and locks.
In some situations, glass replacement alone is enough to correct the issue. Replacing a failed sealed unit can restore both thermal performance and mechanical alignment, without the need for full window replacement.
One of the most common concerns we hear is whether a faulty lock means the entire window needs replacing. In reality, full window replacement is rarely the first or best solution.
Most lock related issues can be resolved through careful window repair, targeted glazing repairs or adjustment techniques such as toe and heeling. These approaches are less disruptive and preserve the character of the existing windows, which is particularly important in many Dorset homes.
Window replacement tends to be necessary only when frames are severely damaged, warped beyond correction or nearing the end of their service life. Even then, it is worth seeking professional advice before assuming the worst.
Minor issues such as stiffness may improve with careful cleaning, but most lock problems benefit from professional assessment. Incorrect adjustments can worsen alignment or damage the mechanism.
This often points to misalignment or frame movement. Temperature changes can cause materials to expand or contract, making the problem feel inconsistent.
Yes, even if the window appears closed. A lock that does not engage fully can compromise security and should be addressed promptly.
A window lock that has stopped working is rarely a cause for panic. In most cases, it is the result of gradual changes rather than sudden failure. With the right approach, the majority of issues can be resolved through thoughtful window repair, glazing repairs or glass replacement.
If your window no longer locks properly and you are based in Dorset or anywhere along the South Coast, having a calm conversation with a specialist can make all the difference. Sometimes, all it takes is a small adjustment to restore smooth operation and peace of mind.
If you would like to have a chat about what is happening with your windows, we are always happy to offer clear, honest advice and help you understand the best way forward.