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UPVC Door Locks When Open But Not When Closed

Understanding the mechanisms of UPVC door locks is critical to efficient and secure home maintenance. An all-too-common issue that homeowners face is when the lock operates correctly while the door is open, but refuses to function when the door is closed.

Understanding this peculiar phenomenon requires a deep dive into the structure of the UPVC door lock and the root causes that might lead to such a problem. UPVC door locks are known for their reliability, durability, and overall excellent performance. However, like any other mechanical systems, they can face occasional difficulties and common problems.

One of the most confounding is the lock working perfectly while the door is open, but creating trouble as soon as the door is shut. So what might be the underlying causes for such an issue?

UPVC Door Misalignment

The core cause of this peculiar locking problem is typically a misalignment involving three major components: the UPVC door, the frame, and the lock itself. In an open position, a door and its lock are free from physical constraints, allowing the lock mechanisms, such as the latch and bolt, to glide effortlessly into place.

The absence of pressure and strain on the locking mechanism means it can function unimpeded, thereby not revealing any underlying alignment issues. However, this scenario dramatically changes once the door is closed. The act of closing the door places pressure and strain on the lock and its associated components.

If there is any degree of misalignment between the lock, the door, and the frame, this pressure exacerbates the problem. The bolt or latch, which previously moved freely, may now resist or even refuse to engage fully into the strike plate.

The reasons for this misalignment depend on a number of factors. Sometimes it’s due to natural house settling over time, causing a dropped door. This is a common occurrence as foundations shift slightly, altering the alignment of door frames – especially in new builds. Installation issues may also be the culprit, if the locksmith’s work wasn’t up to scratch.

If the door, frame, or lock were not properly installed, alignment problems could surface, only becoming noticeable over time. Sadly a rather common problem! Furthermore, environmental factors such as changing temperatures and humidity can cause materials to expand or contract. Hot weather (and even very cold weather) can cause this issue, as extreme heat causes the doors to expand meaning it won’t sit in the right position. Extreme temperatures and UPVC doors don’t mix unless installed properly!

UPVC doors and frames can warp subtly, leading to an alignment issue that directly impacts the functioning of the locking points when the door is closed.

Faulty UPVC Locking Mechanism

A secondary, yet equally crucial cause for the issue of UPVC door locks functioning when open but not when closed, is the presence of a faulty UPVC door locking mechanism. The lock mechanism of a door consists of several internal components – each playing a critical role in the overall function of the lock.

These components typically include the cylinder, the part where the key is inserted and turned; the bolt, the part that extends into the UPVC door frame to secure the door; and the latch, the spring-loaded part that keeps the door properly closed when not locked.

UPVC Door Locks

Over time, through regular usage or due to sudden incidents, these internal components might become damaged or wear out. A worn-out cylinder might have difficulty registering the key, a damaged bolt might not extend or retract correctly, or a faulty latch may not engage or disengage as it should. This degradation in function can prevent the lock from operating smoothly or locking securely when the door is closed.

These issues might not surface when the UPVC door is open. When the door is open, there is no direct pressure on these components, allowing them to move freely, even if they’re slightly damaged or worn out. This lack of pressure can mask the issue, leading to a confusing situation where the UPVC door lock seems to work perfectly when the door is open but fails to function once it is closed.

This anomaly in the lock’s behaviour can lead homeowners to overlook the problem or misdiagnose the cause, leading to inefficient or ineffective solutions. Thus, understanding the role of the lock mechanisms and their potential for wear and damage is vital for diagnosing and solving this common, yet irritating, UPVC door lock issue.

Damaged UPVC Door or Frame

The physical condition of the UPVC door and frame can significantly contribute to this troublesome issue. The structural integrity of a door and its frame plays a pivotal role in the proper functioning of the lock when closed together. Any deterioration, distortion, or damage to these structures can induce uneven pressure on the lock, especially when the door is closed, causing it to malfunction.

For instance, a door can become warped over time due to a range of factors, including exposure to moisture, changes in temperature, or simply through natural aging. A warped door does not fit snugly into its frame. When closed, it may put inconsistent pressure on different parts of the lock, impeding the lock mechanism’s smooth operation.

Similarly, a damaged frame – perhaps due to wear and tear, impact damage, or even pests – might not align correctly with the door and the lock. This misalignment, particularly when the door is closed and locked, could strain the lock and impede its function.

Additionally, the hinges, often an overlooked component of door functionality, play an equally vital role. Bent or loose hinges can cause the door to hang unevenly, leading to inconsistent contact and pressure on the lock when the door is closed, which in turn can impact the lock’s operation.

This cascade of possible physical distortions and damages to the door and its frame highlights the complex interconnectedness of these structures. Each component, even those we might not think about day-to-day, contributes to the overall performance of the door lock, especially when it’s closed and under pressure.

Therefore, maintaining the good condition of these structures is a crucial aspect of ensuring the smooth operation of UPVC door locks.

Fixes for UPVC Door Lock Problems

Before jumping into solutions, it’s important to note that fixing lock problems can be complex and often requires a level of expertise. Improper adjustments might lead to more significant damage. Here are a few common fixes:

UPVC Door Realignment

If the root of the problem lies in misalignment, an attempt could be made to fix this issue by adjusting the door, the frame, or the lock itself. This corrective process could involve several steps, each intricate in its own way.

You might need to tighten or loosen the hinges to realign the door, adjust the position of the strike plate to match the lock’s latch, or even make adjustments to the door itself, such as sanding down high spots. Despite its seeming simplicity, this process can be complex and precise, often necessitating the use of special tools.

Furthermore, this fix demands a degree of mechanical understanding and patience to ensure the alignment is corrected without causing further damage to the door, frame, or lock components.

Replacing UPVC Lock Components

Should the problem lie within the lock mechanisms themselves, replacement of the faulty components might be necessary. This fix involves identifying the specific part that’s causing the issue – be it the cylinder, the bolt, door hinges, the latch, or perhaps some other component within the lock assembly.

Once identified, this faulty component must be carefully removed and replaced with a new, functional part. This task is delicate and intricate, requiring not only a set of specialised tools but also a comprehensive understanding of lock structures and mechanics. It’s important to replace each component with one of equal or better quality.

upvc doors locked

Each component must be correctly installed in its proper place and orientation to ensure the lock functions smoothly. Mistakes or inaccuracies in this process can lead to further issues or even damage the lock beyond repair. Therefore, this task requires a meticulous approach and substantial expertise.

Repairing UPVC Doors or Frame

If the cause of the lock malfunction is a damaged UPVC door or frame, the solution often goes beyond a quick, do-it-yourself fix. Damages to the door or frame may be structural in nature, or due to long-term wear and tear, requiring professional repair or even a complete replacement.

This type of job frequently exceeds the capabilities of most homeowners’ DIY skills. It involves precise measurements, and an understanding of door and lock installation principles that ensure seamless functioning and security.

While a DIY enthusiast might find the prospect of tackling these fixes appealing, they present considerable challenges and potential risks for most people. The interconnected nature of door lock systems and the precision required in their operation mean that even the smallest mistake can lead to even bigger issues.

Improperly done repairs may result in the lock failing to engage, the door not closing properly, or even the door becoming unable to open. In the worst-case scenarios, a botched repair attempt could result in an unsecured door, leaving the home vulnerable to unauthorised entry.

The potential risks and repercussions of these scenarios underline the necessity for professional expertise in addressing issues with door locks, particularly when it comes to dealing with damaged doors or frames.

Professional UPVC Door Repairs

Given the complexity of the issues and the solutions, it is often the best course of action to call in professional locksmiths when dealing with UPVC door lock problems.

Trained and experienced, these professionals have the skills and the tools to diagnose the problem accurately and apply the most suitable solution. Moreover, they can ensure the repair is done correctly, efficiently, and securely.

Additionally, hiring a professional locksmith provides an added layer of assurance. Most locksmiths are insured, meaning that any damage caused during the repair process would be covered.

UPVC Door Issues

While the intricate issue of a UPVC door lock working when open but not when closed can be frustrating, the problem often lies in the alignment of the door, lock, and frame, or in the lock mechanisms themselves.

While DIY fixes might seem appealing, the complexity and delicacy of the task make it advisable to seek professional help. So, the next time you find yourself facing such an issue, don’t hesitate to call a professional locksmith in order to ensure your UPVC door will close properly and lock properly – it’s an easy fix for the pros, while a DIY fix can result in needing a new lock, or even the need to replace the whole door!

It’s the safest and most reliable solution to ensure the security and functionality of your home.

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Murray - Veteran Locksmiths


Murray is a seasoned locksmith with a wealth of expertise in the field. As the founder of Veteran Locksmiths, he combines his extensive knowledge of locks and security, with years of experience servicing the South Coast delivering excellent locksmithing solutions. Murray's dedication and commitment to exceptional service has earned him a reputation as a trusted and reliable expert in the industry.

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Veteran Locksmiths

Local mobile locksmith offering emergency, commercial and domestic locksmith services. Covering the whole of Hampshire, West Sussex and Surrey.


01428 748277

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