There’s something comforting about listening to rain hit the roof until you hear an unexpected drip from the window. For many homeowners, heavy rain becomes the moment they realise that there’s a serious problem. Water is finding its way in. Whether it’s a slow trickle running down the wall or a sudden puddle on the floor, leaking windows during heavy rain are more than a nuisance. They’re a warning sign.
In Perth, where homes face harsh sun, seasonal storms and unpredictable weather patterns, the integrity of your window and door systems is critical. Unfortunately, time, wear, and poor installation can all lead to leaks that appear when your home should be most protected. And when rain teams up with strong winds, minor weaknesses can quickly become major issues.
In this blog, we’ll explain why rain makes these problems more noticeable, break down the most common causes of window leaks, help you spot the early signs of trouble and show why quick DIY fixes rarely offer lasting results. Finally, we cover the most reliable long-term solutions for keeping water out and comfort in.
Why rain makes the problem worse
A window that looks fine on a sunny day can quickly fail under pressure from a storm. Water has a way of finding weaknesses. Rain combined with wind increases the pressure on your window frames, seals and surrounding materials. This leads to water forcing its way through even the smallest gaps or cracks.
When rain is heavy and continuous, it can overwhelm blocked drainage systems or deteriorated sealing. Water can pool around the window, saturate walls and sills, and cause damage to internal finishes. Over time, this leads to water damage, rotting frames and even structural issues.
Common causes of window leaks during heavy rain
There are several common reasons for leaking windows during heavy rain. Understanding these causes can help you identify problems before they become major issues.
Poor or outdated installation
Improperly installed windows are one of the leading causes of leaks. If the window frame was not aligned correctly or flashing was skipped during installation, water can get into places it shouldn’t. This becomes more evident during extreme weather conditions.
Deteriorated window seal or caulking
Sealants break down over time. Exposure to sunlight, temperature changes and general wear cause the window seal to crack or shrink. Once that happens, rain can easily seep in through the gaps. This is especially true for older windows where regular maintenance has not been kept up.
Blocked or damaged drainage systems
Most modern windows are designed with drainage channels that help remove excess water. If these are blocked with debris or dirt, the water has nowhere to go. Instead of draining away, it begins to pool and eventually finds its way inside. A properly functioning system should consistently drain water away from the home.
Warped or rotting window frames
Timber window frames are especially vulnerable to water. Over time, wood absorbs moisture, swells and begins to rot. These changes open up gaps that allow water to enter. Warped frames also make it harder for windows to close tightly, weakening the seal and weather stripping.
Failed glazing or double-glazed window seals
If the seal between panes in double-glazed windows fails, moisture can build up between the glass. This is not only a sign of poor insulation but also an indicator that the window is not sealed against water. When that seal breaks down, it compromises the entire system.
Warning signs to watch for
Recognising the early signs of leaking windows can save you time and money. Look for the following indicators after heavy rain:
- Damp patches or stains around the window or sill
- Peeling paint, bubbling plaster, or swollen timber
- Mould or mildew near the window or on the wall
- Condensation between panes of glass
- Musty smells in the room after rainfall
- Difficulty opening or closing windows due to frame warping
If you spot any of these signs, the leak may have been developing for some time. Prompt action is key to preventing long-term water damage.
Why DIY fixes rarely hold up
While DIY fixes may seem like a cost-effective solution, they often don’t address the root of the problem. Applying a new bead of silicone or temporary seal might block the leak briefly, but it won’t fix deeper issues like frame damage, poor drainage, or improperly installed windows.
In many cases, DIY solutions mask the problem, leading to more serious issues down the line. Applying sealant over damp areas, for example, can trap moisture and accelerate rotting. Without a full understanding of how your window and door systems function together, it’s easy to make things worse.
Regular maintenance is important, but when water is already getting inside, it’s best to consult a professional.
Long-term solutions for leaky windows
Solving leaking windows during heavy rain often requires more than surface repairs. Long-term solutions focus on fixing the structural and material problems that allow water to get in. These may include:
Window replacement or retrofitting
Modern aluminium or uPVC frames offer far superior weather resistance compared to ageing timber or poorly installed units. A retrofit solution allows you to replace the leaking system with minimal disruption.
Replacing or repairing the window seal
If the leak is due to deteriorated caulking or a broken window seal, replacing the affected materials can restore the window’s water-tight performance.
Improving drainage
Blocked drainage systems can often be cleared or upgraded to better manage how your windows drain water. This helps prevent future overflow and damage.
Installing energy-efficient double-glazed windows
Double-glazed windows not only insulate your home but also offer better protection against water intrusion. Newer systems are designed with advanced sealing and drainage to handle extreme weather conditions effectively.
Who to call when you need expert help
Leaky windows are not just annoying. They’re a sign that your home may be vulnerable to more extensive water damage. Whether the issue is caused by a failed window seal, an outdated installation, or poor drainage, a long-term fix is essential.
WA Custom Glass is WA’s first AGGA-accredited company, trusted by homeowners, builders, and strata managers for quality window and door replacements. We use a proprietary removal and installation technique, ensuring minimal disruption and maximum weather protection. All products and installations are backed by a 10-year replacement warranty, and we partner with local manufacturers like Jason Windows to deliver the highest quality glazing systems for WA’s climate.
We specialise in custom retrofitting, double-glazed windows, and modern weather-resistant systems designed to handle Perth’s most extreme weather conditions.
Book your free inspection today
Don’t let leaky windows lead to bigger problems. Request a free quote and inspection from WA Custom Glass. Our expert team will assess your current system and recommend the best solution to protect your home for years to come.
Call today or request your free quote online.
