When moisture gets between two glass panes, the result is window seal failure. This is a rare occurrence since condensation normally stays either of the sides but not both. However, when this happens, glass can break because of the failing seal. To make sure someone doesn’t get hurt, cover the place that is broken with duct tape or something else that will offer protection until the window is repaired.

Explainded below are several ways for window seal repair based on how severe the problem is. 

Why Do Window Seals Fail?

Window seal failure can be caused by:

  • When pressure builds up between two panes most on hot days (commonly known as “heat pumping”)

  • In the colder months shrinking might occur

  • Contraction and expansion of the sealing material

Windows that face the south or the west experience seal failure more frequently since they are exposed to the sun longer. The effect of intense direct sunlight will cause the sealing material that was originally used to deteriorate faster on windows facing these directions as compared to the rest. If you are choosing new windows it's important to consider solid, abiding, transferable warranties (preferable 20 year warranties). This is because the windows will perform better for a long periods, and the transferable warranty will add value when it comes to the resale value.

How to Repair Window Seal

Replacing windows can be an expensive affair. To avoid this expense, you can opt for the repair and restoration alternative. You can do window seal repair in 2 ways - one is doing it yourself or you can call qualified window contractors.

Recognize the Signs of Broken Window Seal

Window gasket (also known as blown seals) will look cracked or missing though it is not so obvious to notice. Sometimes a seal might fail, and you might not realize it until you find condensation in between the glass panes. In some cases, you might find unpleasant mold growing between the glasses. To prevent blown seals that are a result of heat pumping and shrinking due to cold weather, proper and/or upgraded spacers will come in handy. The spacers will give the panes an allowance to breathe without any condensation or pressure buildup. 


Quick Fixes for Window Seals Repair

If you have chosen to fix a blown seal by yourself, the first thing you need to take into account is the source of the leakage. To do this, wait for a cold day and observe the inside of the window. Look out for any cold patches where the sliding window is in contact with the other sash or the seal. These are the two areas vulnerable to failure. The best material to use once you have established the leak is silicon caulk. 

If you think using silicon caulk does not look nice, a better way is to go about it is to check if there is a way you can get rid of the damaged gasket without causing any damage to the window. You can use a pry bar and hammer to get rid of the gasket. Replace it with a wedge gasket and make sure you have put it right. If you realize the gaskets cannot be popped out, you will need to get the window new panes.

Don't worry, the following video shows you a quick and easy way for window seal repair as well as providing caulking tips:


Other Methods to Try

The silicon caulk will shut the sliding window permanently, and you cannot paint over it. If you wish to repaint it, you can use an acrylic caulk. To cut the draft, you can use Morlite, which forms a smooth patty-like weather-stripping. You can always consult at your local hardware shop to get the best alternative. You could also try use adhesive foam weather-stripping that is available in most hardware stores. If you cannot tell where the leaks are, a home energy audit would be helpful. If you notice the leak is where the panes are sliding across each other, it would be wise to call in a professional.


Call a Glazier

Like chimney sweeps, glaziers have been long forgotten by many. However, they are capable of doing an awesome job on your windows. A glazier will charge you way less than a window replacement company, and they will come and repair just the broken portion of the glass.


Call Specialized Companies

Specialized companies take their services a notch higher. They fix the actual problem instead of just replacing the glass. What they do is install a seal and value, getting rid of the condensation till the inner part is dried.

When you window has gone worse when it is rotten, and if you want to be an expert yourself, here is the video that shows how to replace a rotted windowsill:


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  • EliJul.23 16:42
    Thank you so much for explaining how to recognize and resolve a problematic window seal. We just had an intense heat spell in the middle of some summer storms, so the temperature has been fluctuating more than normal and more drastically. Our sliding door glass just popped and the whole surface broke in spiderweb cracks. We had no explanation for it except the temperature changes. I now wonder if it was compounded with a seal problem as well.
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