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Close up of water leaking from the window inside the house.

Worried about window leaks or door leaks at home? Possible causes include:

  1. Insufficient cleaning and maintenance
  2. Extreme weather conditions
  3. Complex home designs that create an opportunity for water ingress
  4. Problems with installation

Join us as we take a closer look at these common causes of leaking windows and doors.

Insufficient cleaning and maintenance

It’s important to regularly clean your door and window tracks to prevent dirt and debris buildup. If left unattended, this dirt can block the weep holes in the tracks, causing water to overflow into your house and potentially lead to costly water damage.

Regular maintenance also helps you spot minor issues before they become a big problem. It also helps prolong the life of other moving parts, such as the rollers.

Pet hair was blocking the weep holes on this window, but now that it has been removed the water can drain away freely again.

Windows and door tracks should be cleaned regularly to avoid blocking the drainage system with pet hair, dirt, leaf litter and other obstructions.

How to Clean Windows and Doors

The good news is that when it comes to leaking windows and doors, one of the most common causes is also the easiest to address.

Learn More

Environmental Factors

Some window and door leaks can be caused by environmental factors, such as:

  • Changing weather patterns: Modern windows and doors are designed to suit our current weather conditions, while older windows from 10, 20, 30 or more years ago were made for the known weather conditions of their time. Stronger weather patterns are becoming a reality, and older windows and doors are just not designed for the increasing strength in weather. Sometimes our service technicians are able to reseal windows and doors making them water and airtight, but if windows are unable to be resealed or modified they will need to be replaced with a higher rated product for today’s weather conditions.
  • Storms and extreme weather conditions: The combination of extreme winds and high rainfall to exposed windows and doors can exceed the product’s drainage system. Water can be forced in through the drainage holes (sometimes in spitting form) and sit in sills and tracks. When this occurs the volume of water coming in exceeds the volume of water going out. These sills and tracks are designed to hold the water and then drain/evaporate away.

If you have exposed windows or doors and are in an area that experiences storms and extreme weather conditions often, consider maintaining your tracks and sills more often than the recommended period to keep drainage holes free of debris, or get in touch to request a service technician to attend and assess whether any product modifications can be made to improve drainage.

Home Design

Some design factors that can cause window leaks and door leaks include:

  • Angled fascia board: A type of fascia board that is installed on an angled roof. Angled fascia boards above windows need to be angled outward to direct water away from the window.
  • Complex window designs: Due to the increased number of joints and seams that are required to construct them, complex window designs need to be considered as potential leak points. The orientation of the house can also be troublesome due to varying factors such as wind direction, sun exposure, and the slope of the roof.
  • Lack of overhangs: Overhangs drain water off the roof and protect wind-driven rainwater from entering through the windows, so a lack of overhangs may be an issue.

Overall, does the house design minimise window and door exposure?

House windows with minimal roof overhang, potentially causing leaky windows during heavy wind-driven rain

Minimal roof overhang exposes the windows during heavy wind-driven rain.

Problems with Installation


Some installation issues that can cause window leaks and door leaks include:

  • Unsupported Sills: The most common cause of installation leaks in sliding doors and windows are unsupported sills. This is difficult to repair once the flooring has been installed and a service technician must assess on a case-by-case basis. Unsupported sills can also lead to separation of mullion blocks and create an entry point for water.
  • Covered Weep Holes: When flooring is installed above weep holes, water will gather in sills and tracks and the water will be unable to drain away.
  • Aftermarket Security Screens: If non-Jason security products have been installed on your Jason frames it is possible they are compromising the drainage system. Some aftermarket security screens don’t take the drainage system into account and block the water from draining out.
Weep hole is not blocked by a Jason Security Screen installed on a sliding door. Some aftermarket security screens may block the drainage system, preventing water from draining out.

Jason Windows security screens are designed to fit Jason windows and doors without blocking weep holes. Some aftermarket security screens block the drainage system.

Useful Resource: How to Identify Window Leaks and Door Leaks

Are you worried about window leaks or door leaks at home? Please use this self-guided tool to identify where the leak is coming from and take a photo or video to help our service team diagnose the problem.