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Windscreen Repair: How to Apply a Windscreen Sealant

Windscreen repair is made easy and accessible with windscreen sealant. Car owners often find moisture seeping through their windscreen, leaving them frustrated and thinking they might need a windscreen replacement. The simple answer is likely windscreen sealant. Using windscreen sealant is a quicker and cheaper solution for minor cracks and flaws, causing irritation, poor visibility, and damage to your car’s interior. 

The anatomy of your windscreen:

Understanding how your windscreen is put together makes understanding why sealant is effective much easier. Your windscreen consists of two layers of glass, ensuring better insolation and stability. Between the two pieces of glass, you also find plastic which provides additional stability and strength. A glue adhesive is used to bond the windscreen to a rubber gasket and the car’s frame creating a seal. 

What is windscreen sealant? 

Windscreen sealant fills tiny cracks along the edge of your windscreen, where it connects with the gasket and car frame. Small cracks or openings here can cause water to leak through, causing damage to your car’s interior and resulting in poor visibility. The liquid sealant oozes into the fractures to ensure that it reaches deep openings. The silicone forges with the glass, which ensures that a tight seal develops.  

Various materials and products are used as sealants, but your best and safest bet is using a silicone sealant. This gel-like formula flows well and is an excellent bonding agent.

Why would you use a sealant? 

Windscreen sealant is an ideal fix for the crevices on the border of the windscreen. There might be a more significant gap between the frame of the car and the windshield in some cars, and this is where moisture can seep in. 

The gap between the windscreen and the car’s frame also develops over time, mainly when rust has formed at the edge of the car frame. Over time the gasket gets brittle, which leaves your windscreen exposed to the elements. An exposed windscreen can eventually develop tiny cracks and openings along the border, and you will start to notice signs of moisture inside your car. 

Instead of replacing your windscreen, sealant can seal off all the cracks, locking out all moisture. Sealant is an easy and quick fix but using the correct product and the correct method is crucial. If successfully applied, the sealant can last for a significant amount of time. 

When to use a sealant? 

It is essential to know when windscreen sealant is the appropriate route to follow. Don’t consider this to be the answer to all windscreen problems. If you have any large chips or cracks that affect your visibility more than it is causing moisture to seep in, let us have a look to see if you require a windscreen replacement

If you don’t feel comfortable applying sealant, we recommend contacting us to assist you in the following steps. 

How to apply the sealant? 

Apply windscreen sealant with care. Be sure that you have familiarised yourself with the process before starting. A pair of steady hands is valuable here!

  1. Your first step would be to identify the cracks and fissures. Use a garden hose to spray your car’s windscreen and spot exactly where moisture seeps in. 
  2. Make sure that you protect your car and your windscreen. Keep in mind that silicone is a liquid that flows rapidly. You don’t want any of the liquid to stick to either your windscreen or car frame. Use two thick strips of masking tape, one strip to protect your car’s paint and another to cover the top part of your windscreen. Tape around the edges of the glass, but be careful not to cover up the crack you want to fill in the process.  
  3. The next check is to ensure that you clean all the surfaces that will be bonded. It is essential to treat any rust on the car with a DIY paint fixer. The paint might need to rest for a day to ensure that it has properly dried. It is then necessary to lightly sand down the glass at the tip where the silicone is placed. Getting rid of any corrosion or dirt will ensure that the silicone moulds to any cracks and forms a neat and robust seal. Any scraping of glass or dirt left behind will compromise your seal. 
  4. Now, you will need to cut a small hole in your silicone tube. Silicone is a substance that flows very quickly, so take care that the hole is the correct size. You want to ensure that the silicone flows steadily when used. 
  5. The best option is to apply the silicone from the top of the screen to allow it to flow down the crevice using gravity. Place the tube in the gap between your car frame and the windscreen. You could use your finger to help smear the silicone along the entire fissure to ensure a good, even spread of the liquid. 
  6. You will now need to let the sealant dry for about ten minutes. Remember to remove the tape on the windscreen and car frame before the liquid is completely set. If you let it dry for too long, you could compromise the seal and struggle to remove the tape properly. 
  7. After removing the tape, it is crucial to let the silicone liquid bond for about a day before exposing your windscreen to the elements. This ensures a tight and proper seal in the future. 


Windscreen repair is made easy at home with a windscreen sealant. Small amounts of moisture escaping into your car do not necessarily mean windscreen replacement. It could be as quick as this DIY solution. Most important is that sealing your windscreen is done correctly to ensure that you prolong the use of your windscreen and not cause more issues that could impact visibility and then safety. If you would like some advice on the best way to solve your windscreen problem, be sure to contact our professional team.