How to Repair a Broken Seal on a Window

When talking about window seals, most people think about three things:

• The caulking around the window frame (i.e. silicone seal);
• The weatherstripping on the window itself; and
• The seal of the insulated glass unit (IGU) with two or more panes.

In a sense, all three of these are, in fact, window seals. When any of the above fails, your windows are likely to leak or get infiltrated with water. Fortunately, in case any window seals are broken in your home, there’s always a way to fix them.

This guide covers how to repair a broken seal on a window. Let’s begin!

The Different Types of Window Seals

Here, we’ll go through an overview of the three types of window seals and their purpose for modern windows:

‍Silicone caulking or silicone sealants are placed around the window frames. These are usually applied as a liquid compound and pressed into place. Once dry, a silicone sealant will serve as a water-resistant seal around the window frame. This window seal is important in keeping out both precipitation and the draft.  

Next up, we have weatherstripping. Weatherstripping is typically placed on the areas of an operable window that have gaps when the window closes. Essentially, once the window is closed, the weatherstripping serves as a barrier to keep air leaks or moisture from entering the gaps. The most common kinds of weatherstripping used for windows are made of foam or tubular vinyl/rubber

Lastly, we have the seal of the IGU or insulated glass unit. Insulated glass units go by many names. They are also known as sealed glass units, sealed window units, insulated glass panels, and so on.

All modern windows that are double or triple-glazed make use of IGUs. The only difference is that double-glazed windows have IGUs with two parallel sheets of glass, while triple-glazed windows have three. The main sign that your IGU(s) have broken seals is the appearance of condensation between the panes. To learn more about how to repair a broken seal on a window for this scenario, keep reading!

Cracked Silicone Caulking

This is the easiest type of window seal to fix with a DIY approach. You will need the following tools:

• Silicone sealant;
• A utility knife or putty knife; and
• A soft rug.

Then, follow along these steps to repair a broken seal on a window frame:

1. Using the putty knife, remove the cracked caulking around the window frame.
2. Then, clean up the area thoroughly using a soft rug.
3. Next, cut the tip of the silicone sealant nozzle slightly so that it has an edge.
4. Apply the silicone sealant, running it along the gap on the window frame. Only apply the amount you need.
5. Lightly run your finger on the silicone sealant so that it is lightly pressed into the frame.
6. In case there are holes on the silicone sealant you applied, apply more silicone sealant to the area and then lightly run your fingertip on the area to smoothen it.
7. Let the silicone sealant dry and wash your hands to remove the silicone sealant from your fingertip.

And voila! Your window’s silicone caulking is fixed.

Failing Weatherstripping

One of the easiest and most versatile types of weatherstripping to use on your window is foam-type weatherstripping. In case your weatherstripping is already failing or flattened, here’s how to replace it with foam-type weatherstripping. You will need the following tools:

• Foam-type weatherstripping;
• A soft rug; and
• A tape measure.

Then, follow along these steps to repair a broken seal on a window:

1. Remove the old weatherstripping from your window.
2. Next, carefully measure your window’s dimensions using the tape measure.
3. Cut out weatherstripping according to the dimensions of your window.
4. Using a soft rug, thoroughly clean up the area where you will apply the new weatherstripping.
5. Remove the adhesive from the back of the foam weatherstripping and carefully stick them into place.
6. Once everything is in place, test your window to see if it closes properly and if the weatherstripping is keeping it sealed when closed.

And that’s it! You now have fresh window weatherstripping to keep out air and moisture.

Broken IGU Seal

The seal of an insulated glass unit is there to keep insulating argon, krypton, or gas in place. Unfortunately, this kind of window seal cannot be fixed with a DIY approach. Once moisture infiltrates the broken seal of your insulated glass unit, you either need the help of a professional or get the glass replaced completely.  

Applying adhesive to make the seal airtight again will not fix this type of window seal problem because there would still be moisture in between the glass panes.

A professional glazier will fix a seal by installing a valve and pump. These will remove the moist air from between the two panes. Then, the glazier will apply a new seal.

If you have argon or inert-gas insulated windows, these glass units will almost always need to be sent back to the factory to be refilled, as very few glaziers will have the equipment necessary to fill a window with gas.

In some cases, it could be cheaper to just replace the entire window with a brand-new model. This would be best if your current type of window is constantly showing problems with broken IGU seals. Doing this would be an opportunity to upgrade your windows to more reliable units from a trusted brand.

Get Windows With Reliable Warranty From Clera

This wraps up our guide on how to repair a broken seal on a window. If you’re looking for newer, more energy-efficient and reliable windows, we’ve got you covered.

For over 41 years, Clera Windows + Doors has been one of the most trusted brands in Canada. At Clera, we provide a lifetime warranty against seal failure. We manufacture and design all of our windows with durability, reliability, and energy efficiency in mind. We also offer professional window installation so that you can look forward to superior window seals all around – from the IGU seal itself to the external weatherstripping and frame caulking.

If you would like to learn more about what we can do for your home, contact our friendly team today!