Window seal repair

When and how to replace the gaskets of PVC windows?

After a few years of use, your windows come to suffer the effects of time and sometimes require parts to be changed. This is the case, for example, of the seals which are affected by the atmospheric conditions to which the windows are exposed, but also by the fact of frequently opening and closing the leaf. When and how to change PVC window seals to double or triple glazing.


The main reason why a PVC window seal wears out faster than expected by the manufacturer is often the lack of maintenance. Although cleaning and maintaining the joints in good condition is not a difficult task, it takes a lot of time, especially when your home has a large number of windows.

If you find yourself moving into an apartment or a house where the gaskets no longer fulfill their role – let air or water pass through – you will have to plan to replace the gaskets with new ones.


As we have just seen, poorly maintained seals must be replaced to restore the window to a good insulation performance. The other reason that pushes to have to change the seals of your windows is age. Gaskets usually perform their function for 10 years, but in order to achieve such a satisfactory result, you need to take care of them regularly.

First of all: air leaks and infiltrations. The window may be closed, but do you still feel the movement of the air between the sash and the frame? It is probably that your window seals are too old and that they need to be replaced. In this case, the double-glazed or triple-glazed PVC window seal must be replaced immediately to ensure good thermal and sound insulation.

Secondly: degradation due to age. Joints that are not properly preserved will suffer the harms of time and can become clogged. The rubber used in the seals is very durable , but in a situation where the window is opened and closed several times a day during the day, it is subjected to a rather difficult test. That is why it is recommended to regularly use a maintenance agent to clean and maintain the joints.

If you notice that the seals have become air or water permeable, or that they are hard and break when touched, the time has come to replace them.


Changing the seals of a window is not a complicated task, but first you will need to know the window profile you have. It is useful to check on the nameplate: the model of the window, the size, the type. With this information and the production number you will only have to contact your OKNOPLAST dealer/ installer. Each window is unique, which manifests itself up to the arrangement of the joints which may be different from one model to another. That is why we strongly advise you not to buy universal joints, nor to buy them without clearly specifying the model of your window to a specialized seller.

Keep in mind that if your windows are already several years old and they are no longer manufactured, it may take a long time to process such an order. It is therefore important not to do it at the last minute just before winter.

If your new joints are in the form of an adhesive tape pre-cut to size, the task will be very easy. It is enough to remove the old rubber, clean the grooves in the window frame and place a new gasket inside. Remember, however, that cutting the joints to the correct size usually entails additional costs. It will be cheaper to order a continuous strip and adjust it to the dimensions of the window. To do this, it is recommended to position the seal on the window and adjust the cutout to the correct size.

It may be that the joints of your window are welded in the corners. In this case, we do not recommend replacing them yourself. We invite you to contact the OKNOPLAST premium dealer closest to you.

Now you have all the necessary information to properly maintain and, if necessary, change your PVC window seals. A quality and regular maintenance of your joints will be the key to allow your windows to extend the longevity of their performance.

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Window Repair and Restoration Services in Boston