Windows are an essential part of any home. They let in natural light, fresh air, and can add a touch of style to your décor. 

But when your windows start to leak, it could be a sign of something much worse. Leaks aren’t just a pain to clean up. Leaking water can lead to wood rot and structural damage to your home. This can cost you tens of thousands to repair in the long run. 

The good news is: You don’t have to settle for tired, worn-out, leaky windows! In this article, we’ll explain the top 5 reasons why windows leak and how you can keep your windows sealed tight, even through the worst thunderstorms. 

The Top 4 Reasons Why Windows Leak

Here are some of the most common reasons for window leaks during spring rain and wind storms.

1. Separating Seams  

When a window is installed in your home, it has to seamlessly connect with your trim, siding, roof, gutters, and walls. Installers do this by sealing the windows to the surrounding materials. Exposure to the sun, missing paint, and age can all cause  the seam that seals the space between your window and its surrounding structure to crack or loosen.

As a seam separates, water seeps through the cracks. This can lead to interior or exterior damage, depending on where the gaps have formed. The appearance of cracks in the sealant around your windows is a key sign that this has happened. Also look for damage to the materials around the windows, like the wood siding underneath it.

2. Worn or Damaged Weatherstripping

Damaged weatherstripping is one of the most common reasons for windows to leak. If your weatherstripping is worn or damaged, it might not create a proper seal when closed, allowing water to seep in. 

You can usually tell when you need to replace your weatherstripping if you feel a draft coming from around the window or if you see cracks or gaps in the material. You can also determine whether the weatherstripping needs replaced if you are able to see light coming through the gap or if the weatherstripping is flat and matted down.  

An easy way to test for damaged weatherstripping without leaving your living room is to close your windows on a windy day. If you can feel any air coming in from the inside, it's time to replace the windows.

3. Improper Window Installation

Another common reason for a leaky window is improper installation. We all assume the team that installed our windows did it the right way. Unfortunately, some installers are better than others when it comes to skill and attention to detail.

If your windows are not installed level or plumb, it can create gaps that allow water to seep in. In addition, if the flashing was not installed correctly or if there are any gaps in the installation, water can also enter through those areas.

If you're not sure whether or not the contractor installed your windows correctly, it's best to hire a professional to take a look. They will be able to tell you if there are any problems with the installation and can fix them accordingly.

Hiring a professional might seem like an unnecessary expense, but it could save you money in the long run by preventing further damage to your home.

4. Cracked or Broken Glass

Finally, another common reason for windows to leak is cracked or broken glass. If there is any damage to the glass, it can create gaps that allow water to seep in—especially if you have old single-pane windows. In addition, if the sealant around the glass is damaged, it can also cause leaks.

If you see any cracks or breaks in your window glass, it's essential to have them repaired as soon as possible. This will help prevent water leaks, but it will also help improve the overall energy efficiency of your home.

Now that we've explored why windows leak, here are a few ways you can keep them from leaking.


4 Ways to Keep Windows From Leaking

Here are a few simple things you can do to help prevent a window leak:

1. Determine Where the Leak Is Coming From

The no. 1 way to fix a leak is to identify where it’s coming from.  You want to be sure you solve the leak at it's source so you don't have to pay to fix it twice. And just because you see water leaking out of a window doesn't mean water is coming through the window on the outside.

Let me explain: If there’s a crack in your siding, water can run down the side of your house, soak into the top of your window, and start to seep inside. The window itself could be perfectly fine. And if you were to replace the window in this case, you could find yourself facing the exact same leak years down the road.

Another example can occur if the window on the story above where you found the leak has a rotted seal. Water can soak into the seal, drain down the wall, and make its way into the bottom window. Again, there’s absolutely nothing wrong with your bottom window in this case. If you were to replace it, the leak would come right back.

So how do you solve the mystery of where the leak is coming from? You start with two people: one on the inside and one on the outside. On a dry, sunny day, have the person on the inside spray a hose against where you think the leak is coming from for 10 minutes.

After 10 minutes, if you see no leak, it’s time to check for another possible cause, like nearby siding. Start from the top down (so if you have a window above the leaking window, check it first), checking the window where the leak is visible last.

2. Replace the Exterior Caulking 

Once you have located where the water is sneaking in from, you’ll want to apply caulk to the area to seal any gaps or cracks. Be sure to use a high-quality exterior sealant like commercial-grade Solar Seal 900, which we personally use on our projects. 

Another good option is OSI Quad Max, often available at home improvement stores. It comes in clear or colors to match your home.  

You need to purchase the sealant that correct for your application. Unfortunately, this can be easy to overlook. There is interior and exterior sealant. Some can be applied dry, some must be applied wet, and others must be applied inbetween certain temperatures. Read the instructions thoroughly before you apply it to ensure you get it right the first time.

3. Replace the Weatherstripping 

If caulking alone doesn’t solve the problem, weatherstripping is your next best step. Weatherstripping can create a proper seal around your window to keep water out, whether its coming from above, below, or along the sides of the panes.

There are various types of weatherstripping available, like foam, felt, and rubber. Choosing the right kind of weatherstripping for your home is important as some are better suited for certain climates. Not all types of weatherstripping will work for your specific window.

The first place to start is to call your window manufacturer and see if they can send you some of the exact weatherstripping for your window. If that doesn't work, you can find similar types online or at a specialty store.  

You might also consider calling your local window and door company that may have some industry-specific weatherstripping for part of their service department. They may be willing to sell it to you.

4. Replace Your Windows

If none of the previous steps have stopped the leak or your windows are in the 20-30 year range, it might be time to consider replacement. Over time, windows can settle and warp, creating gaps and allowing water to seep in. If this is the case, you need to get the windows replaced sooner than later. Otherwise, that leaking can lead to costly wood rot.

A great option is Marvin Essential Windows. Marvin windows are one of our top brands to recommend for durability because they’re made with strong, high-performance fiberglass, which is eight times stronger than vinyl and three times stronger than wood. 

Marvin Essential Windows come in a variety of styles to match your home’s exterior. The windows also come with the Marvin Bright View screen mesh, which is fiberglass designed to keep out bugs and debris while still allowing for fresh air and ventilation. It also repels water, dirt, and grime while allowing natural light into your home for a sharp, vivid view.

If Marvin Essential Windows aren’t a good fit for your home, there are other brands for you to choose from. A dependable window installation company can walk you through your options and help you select the best choice for your home, your style, and your budget.


Upgrade Your Leaky Windows with Windura

Leaky windows can be a significant source of frustration. Fortunately, by following the tips above, you can stop window leaks before they cause damage or costly wood rot. 

if you'd like a professional to handle your window problems, then contact Windura! With over two decades of experience, Windura has helped countless families in the Kansas City area feel comfortable and secure in their homes. 

Often, you can tell a window is prone to leaking before thunderstorms even hit. Our team will take the time to evaluate your windows thoroughly to identify any potential damage that may be hidden underneath the surface. Even if you end up not choosing our service, you will walk away from your free consultation with a clear idea of the problem and how you can fix it!

Give us a call today to schedule your free in-home consultation. 

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Topics: Maintenance Tips, Windows, Weatherproofing Your Home, Energy Efficiency