Troubleshooting Your uPVC Sash Window: Why It Won’t Stay Up and How to Fix It

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Identifying the Issue

When your uPVC sash window refuses to stay up, it’s more than just an inconvenience. Understanding the root cause is the first step towards rectifying the problem. There are three common issues that could be causing this nuisance.

1. Dysfunctional Sash Window Balance Mechanism

The sash window balance mechanism plays a crucial role in ensuring smooth operation. If this mechanism fails, your window might struggle to stay open. Signs of a faulty balance mechanism include difficulty in opening or closing the window, or even an uneven alignment when the window is partially open. This problem often occurs due to wear and tear over time.

2. Deteriorated or Faulty Window Hardware

Another common culprit behind a sagging uPVC sash window is worn or damaged hardware. The locks, handles, and hinges that are essential for the window’s functionality might have deteriorated. When these components are compromised, the window might not latch securely, causing it to slide down.

3. Disproportionate or Misaligned Sashes

Sometimes, the issue lies in the alignment of the sashes. If they are imbalanced or misaligned, the window won’t stay up. Misalignment can occur due to various reasons such as settling of the house, changes in weather, or improper installation. When the sashes don’t fit perfectly into their frames, the window tends to droop.

The Significance of Timely Repairs

Understanding why your uPVC sash window isn’t staying up is crucial, and so is addressing the problem promptly. Ignoring this issue can lead to several complications, making it imperative to act swiftly.

1. A Non-Functional Sash Window Jeopardizes Safety

A sash window that won’t stay up poses significant safety risks. It might unexpectedly slam shut, causing injury to anyone in its vicinity. This is especially concerning if you have children or pets in the house. Ensuring your window stays in place is vital to maintaining a secure living environment.

2. Impaired Energy Efficiency Due to a Damaged Sash Window

A sash window that doesn’t close properly creates gaps, letting in drafts and external noise. Additionally, it compromises the energy efficiency of your home. During hot summers or chilly winters, your HVAC system has to work harder to maintain a comfortable temperature, leading to higher energy bills. Fixing your sash window promptly ensures your home remains energy-efficient.

3. Swift Repairs Extend the Overall Lifespan of Your Sash Window

Regular maintenance and timely repairs are key to prolonging the lifespan of any fixture in your home, including your uPVC sash window. Addressing issues promptly prevents them from escalating into more significant problems. By taking care of the balance mechanism, window hardware, or sash alignment, you’re ensuring your window serves you well for years to come.

Diagnosing the Issue

Before you can fix the problem, you need to diagnose it accurately. Start by inspecting the window closely. Check for visible signs of wear on the balance mechanism. If the hardware looks rusty or worn out, it’s a clear indication of what might be causing the issue. Additionally, observe the alignment of the sashes. Do they sit flush in their frames, or is there a noticeable gap?

If you’re unsure about the diagnosis, it’s advisable to consult a professional. A trained technician can assess the window thoroughly, identifying the exact cause of the problem. This expert analysis ensures that the repairs are precise, addressing the root cause rather than just the symptoms.

Addressing the Issue

Once you’ve identified the problem, it’s time to address it effectively. For a faulty sash window balance mechanism, replacing the balance springs or pulleys might be necessary. This task requires precision, and if you’re not confident in your DIY skills, it’s best to hire a professional to do the job.

If worn or damaged hardware is the issue, replacing the locks, handles, or hinges might be the solution. Opt for high-quality replacements to ensure the longevity of the repairs. Lubricating the moving parts can also enhance the window’s functionality, preventing future issues.

In the case of misaligned sashes, adjusting the frame or realigning the sashes might be necessary. This task demands careful attention to detail to ensure the window opens and closes smoothly. A professional can perform these adjustments accurately, restoring your window to its optimal condition.

Preventive Measures for Future Maintenance

Once you’ve fixed your uPVC sash window, it’s essential to implement preventive measures to avoid similar issues in the future. Regular maintenance is key. Periodically inspect the window for any signs of wear or damage. Lubricate the moving parts to prevent friction, which can lead to wear and tear. Keeping the window clean also contributes to its longevity by preventing dirt and debris from interfering with its operation.

Additionally, consider installing weatherstripping around the window. Weatherstrips act as a barrier, sealing any gaps and preventing drafts. This not only enhances energy efficiency but also protects the window from the elements.


If double-hung sash windows not staying up?

If double-hung sash windows are not staying up, it could be due to issues with the balance system. The balances might be worn out or damaged, preventing the window sashes from staying in the desired position. It’s advisable to consult a professional window repair service to assess and fix the problem, ensuring the windows operate smoothly and securely.

How to fix old windows that won’t stay up?

To fix old windows that won’t stay up, you can start by cleaning the window tracks to remove any debris or buildup that might be obstructing smooth movement. Next, check the window balances – these might need replacement if they are worn out or damaged. Tightening the screws on the window hinges and applying lubricant can also help. If these steps don’t work, consulting a professional window repair service is recommended for a more thorough inspection and solution.

What holds a window sash up?

A window sash is typically held up by a system of counterweights, springs, or friction hinges. In traditional double-hung windows, counterweights connected to the sash with ropes and pulleys create a balance, allowing the sash to stay in position when opened. Modern windows often use spring balances or friction hinges to achieve the same effect. These mechanisms create resistance, ensuring the window sash stays open at the desired height and can be easily closed when needed.

Why do sash windows drop?

Sash windows may drop over time due to wear and tear of the counterweight or spring balances, which lose their effectiveness. Additionally, the window frame might warp or deteriorate, causing misalignment and preventing the sash from staying in place. Poor installation or lack of maintenance can also contribute to sash windows dropping. Addressing these issues through repairs or replacements of worn-out components can restore the functionality of the windows and prevent them from dropping further.

How to fix it if my sash window keeps falling down?

If your sash window keeps falling down, you can start by cleaning the window tracks to remove any debris that might be causing friction. Check the balance mechanism (either weights and pulleys or spring balances) to ensure they are functioning correctly; if not, they might need repair or replacement. Tighten any loose screws or hardware on the window and consider adding weather stripping to improve the fit, which can help the window stay in place. If these steps don’t work, it’s best to consult a professional window repair service to assess the issue and provide a tailored solution.

About the author

Glen Ramsey, who presently holds the positions of customer support and content manager, is a cherished member of the Sash Window Refurbish team. He is in a unique position to provide advice on all questions pertaining to the renovation of historic windows because he has a wealth of experience in all elements of window renovation, dealing with clients regularly and assisting them in choosing the best window-related course of action. He oversees the creation of information for all of our platforms in his capacity as content manager, including web content and other materials. Glen has witnessed the whole gamut of Sash Window Refurbish's window restoration activities, from our work on significant listed Georgian homes to a wide variety of smaller-scale private residential projects.


My technician Andrew replaced all my sash windows that had rotten sills. Accessing the rotten sills was not an easy task. He explained to me what needed to be done in order to fix the problem. He is a great person and I’m happy that he was the one who did the job. He is reliable, tidy, friendly and very professional. I highly recommend him.



I hired Andrew and Alex a while back to repair my damaged sash windows. They were was very considerate and very patient as he did his job. A few days ago, I had another problem with one of my sash lock keys and I called him again to come and fix the problem. I’m very impressed that Liam responded quickly and he not only fixed the problem but he also gave me a spare key. What a great after sales service!

Alan W.


I’m very impressed with the new windows that Andrew installed and also the reconditioning job that he did on other sash windows. The quality of his work is by far more superior than what we got when we hired another company a few years back. We will certainly hire him again if any window work arises

Kelly (Sleaford)


Our decorator referred us to Andrew because some of the work needed a window expert. Andrew together with our decorator did a fantastic job. The work was done efficiently and to the highest standards. Andrew is understanding, committed and very professional. I recommend him without any hesitation.

Steaven Reader


Alex did a great job in fixing windows in our terraced house. The windows were broken, frames damaged and the wood was also rotten. Alex's job was high quality and he did it pretty fast. I was also very impressed that he was considerate of my son’s asthma condition and maintained cleanliness. Top work.



Andrew just recently replaced three sash windows in my Edwardian house. He also repaired and replaced some sills and draught proofed three windows. In addition to that, he also did some carpentry work. What I like the most about Liam is that he did a clean job. He is very professional and always updated me about the timescales and costs. He also did his job with minimal disruptions. I highly recommend him.

Cris M.