Common window faults and how to fix them

There’s no doubt that installing uPVC windows and doors in a property is a great home improvement but from time-to-time faults can develop. Do not worry, Cheltenham Glass and Glazing are here to guide you through simple fixes, or to step in if you need more assistance.

Here are some of the common window issues our Gloucestershire customers have contacted us about in the past, and what we recommend you do to fix the fault.

Help! My window is stuck shut. What should I do?

Part of the structure of a UPVC window frame is a rubber gasket. This gasket has a really important job, acting as a seal to prevent draughts entering your home through the window opening. If a window is not opened for some time the rubber can become stuck to the frame.

If you find that your window is stuck shut it is really important that you do not try to force it open. The rubber could rip and therefore need replacing.

You should work carefully to prise the rubber gasket away from the UPVC window frame, using either a blunt flat blade or an old bank card, sliding it around the frame slowly so that the seal is released and the window can open again.

Finally, using a soft cloth or sponge and warm soapy water, you should clean the window frame where it was stuck to remove any residue left behind by the rubber gasket. You should also clean the gasket in the same way and let it dry naturally before closing the window again.

My windows keep sticking in warm weather. Why does this happen?

During warm weather uPVC will expand a little which can cause temporary issues with the ability to open and close windows.

This is normal and units are usually built to accommodate some expansion and contraction of the uPVC. However this may make opening and closing of windows and doors a little tricky until the temperature drops back to normal levels. In extreme heat (i.e. over 40°C) expansion of up to 2.4cm has been seen in uPVC although this is a rare occurrence.

If you find that your uPVC windows and doors do stick due to warm weather, please be assured that this is normal and shouldn’t cause any lasting damage, with the uPVC returning to normal when cooler. You can attempt to cool uPVC frames by spraying them with cold water and wiping with a damp cloth to help shrinkage.

If you experience problems with sticking uPVC frames in colder weather, please don’t be tempted to warm the frames up as this could cause the uPVC to warp and crack. Contact us for more information and advice.

My windows are really stiff. How can I fix this?

Where a uPVC window has become stiff to open or close it is possible to improve this by lubricating the hinges with a simple spray of WD40 or a drop of light oil.

In addition, hinges may become too loose, causing windows to blow shut or not stay open as intended. In this case the friction hinge can be adjusted using a screwdriver. Friction hinges can also be adjusted to correct stiffness when operating windows.

If you still have problems after lubrication and adjusting the friction hinge of your uPVC window, please get in touch with us at Cheltenham Glass and Glazing by calling us on 01242 238887 so that we can assess the situation and recommend next steps. We will repair or replace faulty units free of charge if they are still within their warranty period.

Why is there condensation on the outside of my new UPVC double glazing?

There are a number of causes of condensation where uPVC windows are concerned, but what matters is where the condensation is.

In this case, don’t be alarmed! Condensation on the outside of a double-glazed window means that it is working really well. The argon gas filled chamber between the two panes of glass is acting as insulation, preventing heat from inside the room from escaping outside whilst also preventing cold air from getting in.

External condensation occurs when the external air temperature is lower than inside. Moisture carried within the cooler air condenses when it touches the insulated glass, forming the water droplets that you see.

Be glad that your double glazing is doing its job and is helping to keep your house warm!

I’ve noticed condensation between the panes of glass in my window. What has happened?

Unfortunately, condensation or misting between the panes of glass in a uPVC window means that the seal around the window has failed or the glass has cracked, allowing the argon gas that usually fills the gap inside the window to escape.

In the case of a failed seal the glazed unit will either need to be repaired or replaced. Your technician from Cheltenham Glass and Glazing will be able to advise you as to whether the unit can be repaired or will need replacing, with good, honest advice. If you live in or near Gloucestershire and have a misted window, simply give us a call. We’re always happy to help.

What is causing puddles of water on the windowsill in my room?

Excess moisture in a room is a common cause of windowsill puddles – due to the natural process of condensation. Tiny molecules of water will condense when the air it is carried in touches a cooler surface, in this case, a window pane.

Here are our top tips for reducing the amount of moisture in the air:

·        Keep your home well ventilated, open windows daily to keep air moving through rooms

·        Avoid drying clothes indoors wherever possible to try to reduce the amount of moisture in the air

·        Consider improving the insulation in your home

·        Use central heating to gently maintain a constant, comfortable room temperature

·        Use a dehumidifier to help dry clothes if you have no alternative drying space

·        Always use an extractor fan when cooking or having a bath or shower

And finally, always wipe away condensation on windows and the puddles that appear on your windowsills to help reduce moisture levels within your home.

The leadwork in my window has changed colour. Can you replace it?

The natural oxidisation of leaded windows can happen when new leadwork is exposed to the elements for the first time. The surface of the lead will gradually oxidise to form a natural patina. When exposed to moisture, lead can also discolour for a short time. This spotting or powdery finish will clear when the lead has gone through the oxidisation process.

My front door sticks when I open and close it. Has something moved?

From time to time you may notice that your uPVC door becomes harder to open and close which is something that Cheltenham Glass and Glazing sometimes receives requests for help about. This may be due to the expansion of materials used in the door in warm weather.

Another cause of a door sticking may be that the hinges have dropped slightly or the frame has become misaligned. If you think that this might be the case simply get in touch and our friendly technicians will help to put things right.

The handle on my transom window is really hard to open. Why is this?

If you haven’t used a handle on a uPVC window frame for some time you may find that it seizes up and becomes very stiff. At Cheltenham Glass and Glazing we would recommend that windows are frequently opened and closed.

This has two benefits. Firstly, the handle (and hinge) mechanisms will be prevented from seizing up and secondly, you will allow air exchange as fresh air will come into the room.

As mentioned earlier, we would also recommend that moving parts of window frames such as handles and hinges are cleaned and lubricated at frequent intervals to prevent them becoming stiff.

Why have my white UPVC window frames gone yellow?

Thankfully, the discolouration of uPVC is far less frequent than it used to be as the quality of materials used in uPVC frames is far superior these days. However, yellowing uPVC is usually a sign of old age, as the plastics react with sunlight and UV rays.

If you live near Cheltenham or the wider Gloucestershire area and would like to discuss replacing your yellowed window frames please contact Cheltenham Glass and Glazing for a competitive quote.


Providing fast, friendly advice and fitting, based on over 10 years experience in the glass fitting industry, our staff take pride in delivering the best possible service to all our customers. So, if you are looking for the best aluminium and UPVC windows & doors Cheltenham has to offer, contact Cheltenham Glass and Glazing today.

01242 238 887

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1 Tremblant Close, Cheltenham, GL52 5FL